Improve Nonmotorized Transportation

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Sector
Transportation
Mode
Cut Emissions
Cluster
Shift to Alternatives
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Many people in a crosswalk viewed from above
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Summary

We define Improve Nonmotorized Transportation as increasing any form of travel that does not use a motor or engine. In theory, this includes a huge range of transportation modes, including horses, cross-country skis, sailboats, hand-operated rickshaws, and animal-drawn carriages. In practice, pedestrian travel and cycling account for most nonmotorized utilitarian passenger travel.

Income & work,Health
Nature protection,Air quality
Description for Social and Search
Improve Nonmotorized Transportation is a Highly Recommended climate solution. Walking and cycling produce zero operational greenhouse gas emissions, promote health, and require minimal infrastructure.
Overview

Travel shifted from motorized to nonmotorized transportation saves GHG emissions – mostly CO₂, but also small amounts of nitrous oxide and methane (Center for Sustainable Systems, 2023) – that a fossil fuel-powered car would otherwise emit. 

We divided nonmotorized transportation into three subcategories: 1) pedestrian travel, including walking and the use of mobility aids such as wheelchairs; 2) private bicycles owned by the user, meaning that they are typically used for both the outgoing and return legs of a trip; and 3) shared bicycles, which are sometimes used for only one leg of a trip and so have to be repositioned by other means.

Pedestrian travel

Pedestrian travel (including both walking and travel using mobility aids such as wheelchairs) has the advantage of being something that most people can do and often does not require special equipment or dedicated infrastructure (although some infrastructure, such as sidewalks, can be helpful). Pedestrian travel is 81.7% of global urban nonmotorized pkm. 

Private bicycles

Private bicycles cost money and require maintenance but enable travel at much faster speeds and therefore longer distances. Private bicycles are 13% of global urban nonmotorized pkm.

Shared bicycles 

Shared bicycles eliminate the financial overhead of bicycle ownership, but usually only permit travel within specific urban areas and sometimes between established docking stations. Shared bicycles are 5.1% of global urban nonmotorized pkm. 

Note that we did not include electric bicycles in this analysis. Electric bicycles are analyzed as a separate solution.

While improving nonmotorized transportation can be a valuable climate solution virtually anywhere, we limit our analysis to cities due to the high number of relatively short-distance trips and the abundance of available data compared with rural locations.

The fuel for cycling and pedestrian travel is the food the traveler eats. When the traveler metabolizes the food, they produce CO₂. Some studies factor the GHG emissions produced by the added metabolism required by nonmotorized transportation into its climate impact because of the emissions that come from the food system (Mizdrak et al., 2020). This is controversial, however, because it is unclear whether pedestrians and cyclists have a higher calorie intake than people who travel in other ways (Noussan et al., 2022). Furthermore, additional food eaten to fuel physical labor is not typically counted in life-cycle analyses. This analysis, therefore, does not consider the upstream climate impacts of food calories that fuel cycling, pedestrian travel, driving, or any other activity.

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Credits

Lead Fellow

  • Cameron Roberts, Ph.D.

Contributors

  • James Gerber, Ph.D.

  • Yusuf Jameel , Ph.D.

  • Daniel Jasper

  • Heather Jones, Ph.D.

  • Heather McDiarmid, Ph.D.

  • Alex Sweeney

Internal Reviewers

  • Aiyana Bodi

  • Hannah Henkin

  • Yusuf Jameel, Ph.D. 

  • Heather McDiarmid, Ph.D.

  • Ted Otte

  • Amanda D. Smith, Ph.D.
Effectiveness

Nonmotorized transportation can save 115.6 t CO₂‑eq /million pkm, compared with fossil fuel–powered cars (Table 1). This makes it a highly effective climate solution. Every trip shifted from a fossil fuel–powered car to cycling or pedestrian travel avoids most, if not all, of the GHG emissions associated with car travel. Nonmotorized transportation effectiveness is calculated by taking the share of each mode and multiplying it by its effectiveness, and adding this value from all three modes. 

Cars produce 116 t CO₂‑eq /million pkm (International Transport Forum, 2020; IPCC, 2023; Montoya-Torres et al., 2023; TNMT, 2021; Verma et al., 2022). Note that this value does not correspond directly to the estimates arrived at in most of these references because it is common practice to include embodied and upstream emissions in life-cycle calculations. Because we do not include embodied and upstream emissions (which are accounted for in other solutions), our estimate for the current emissions from the global vehicle fleet comes from an original calculation using values from these sources and arrives at a lower figure than they do.

Pedestrian travel and private bicycles have negligible direct emissions (Bonilla-Alicea et al., 2020; Brand et al., 2021; International Transport Forum, 2020; Noussan et al., 2022; TNMT, 2021). This means people avoid all direct GHG emissions from driving fossil fuel–powered cars when they use nonmotorized transportation instead. Thus, shifting from cars to nonmotorized transportation saves 116 t CO₂‑eq /million pkm, not including indirect emissions, such as those from manufacturing the equipment and infrastructure necessary for those forms of mobility. Life-cycle emissions from cycling are approximately 12 t CO₂‑eq /million pkm, most of which come from manufacturing bicycles (Bonilla-Alicea et al., 2019; Brand et al., 2021; ITF, 2020; Montoya-Torres et al., 2023; Noussan et al., 2020; TNMT, 2021), while emissions from pedestrian travel are negligible (TNMT, 2021). These life-cycle emissions are not quantified for this analysis, but may be addressed by other solutions in the industrial sector.

Shared bicycles provide fewer emissions savings than privately owned bicycles do. Shared bicycle schemes have direct GHG emissions of 7.49 t CO₂‑eq /million pkm, about 109 fewer than the average fossil fuel-powered car. Because people sometimes use shared bicycles for one-way trips, the bike-sharing system can become unbalanced, with fewer bicycles in places where people start their journeys and more bicycles in places where people end them. This is fixed by driving the shared bicycles from places with surplus to places with shortage, which increases emissions. The total increase in emissions caused by this can be mitigated through measures such as using electric vehicles to reposition the bikes or incentivizing riders to reposition the bicycles themselves without the use of a vehicle. 

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Table 1. Effectiveness at reducing emissions.

Unit: t CO₂‑eq /million pkm, 100-yr basis

Nonmotorized Transportation
25th percentile 99.33
mean 118.8
median (50th percentile) 115.6
75th percentile 136.9
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Cost

Driving a fossil fuel–powered car has private costs (i.e., those that accrue to the motorist themselves) of US$0.25/pkm and public costs (for roads, lights, traffic enforcement, etc.) of US$0.11/pkm. It generates public revenues of US$0.03/pkm from taxes, fees, fines, etc. (AAA, 2024; Burnham et al., 2021; Gössling et al., 2019). This means that its net cost to the passenger is US$0.32/pkm. Cars also have externality costs, such as the cost of health care due to road injuries or air pollution (Litman, 2024). We do not factor these externalities into our cost analysis.

Nonmotorized transportation (costs weighted by mode share) has private costs of US$0.08/pkm and public costs US$0.04/pkm. It produces no revenues to the user. It has a net cost of US$0.12/pkm and saves US$0.21/pkm compared with car travel. This equals a savings of US$1,771/t CO₂‑eq (Table 2).

Pedestrian travel has private costs of US$0.09/pkm (mostly for shoes) and public costs of US$0.1/pkm (for sidewalks, staircases, bridges, etc.). It produces no new revenues. It has a net cost of US$0.10/pkm and saves US$0.23/pkm compared to car travel (Gössling et al., 2019; Litman, 2024). 

Private bicycles have private costs of US$0.06/pkm (for the cost of the bicycle itself, as well as repairs, clothing, etc.) and public costs of US$0.002/pkm (for bike lanes and other infrastructure). They produce no new revenues. They have net costs of US$0.07/pkm and save US$0.26/pkm compared to car travel (Gössling et al., 2019; Litman, 2024). These costs are cheaper than those of pedestrian travel on a per-pkm basis because, while a bicycle costs more than a pair of shoes, it can also travel much farther.

Shared bicycle systems have different cost structures. They can be very expensive (US$9.00/km in London), free (Buenos Aires) and very inexpensive (less than US$0.00 in Tehran) based on what operators charge users. Rides are usually priced by time rather than distance (DeMaio, 2009). Calculations were made as to distance covered by time to arrive at a price per km (CityTransit Data, 2025; Fishman & Schepers, 2016; Pro Cycling Coaching, 2025). Assuming that this roughly covered operating costs, it means that these systems cost US$0.22/pkm more than car travel.

An important consideration for each of these is that we must divide the cost of a bicycle, car, pair of shoes, or piece of infrastructure (road, bike lane, sidewalk) by the pkm of travel it supports over its lifespan. This means that nonmotorized transportation, which is cheaper but slower than cars, can have less of a cost advantage per pkm than might seem intuitive, and is part of the reason why cycling is cheaper per pkm than pedestrian travel. In addition, all of these estimates are based on very limited data and research and should be treated as approximate. Lastly, per-pkm infrastructural costs of cycling and pedestrian travel will decrease as cyclists and pedestrians use the infrastructure more intensively.

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Table 2. Cost per unit of climate impact.

Unit: 2023 US$/t CO₂‑eq , 100-yr basis

Nonmotorized Transportation
median -1,771
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Learning Curve

Walking and cycling are mature technologies, so the concept of a learning rate is not applicable.

There is also limited opportunity for cost reductions in cycling or pedestrian infrastructure built using construction techniques very similar to those used in the road industry. However, while learning effects might not do much to reduce the costs of nonmotorized transportation infrastructure, they could do a great deal to improve its effectiveness. Safe cycling infrastructure, in particular, has improved considerably over the past few decades. This could continue into the future as best practices are further improved.

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Speed of Action

Speed of action refers to how quickly a climate solution physically affects the atmosphere after it is deployed. This is different from speed of deployment, which is the pace at which solutions are adopted.

At Project Drawdown, we define the speed of action for each climate solution as emergency brake, gradual, or delayed.

Improve Nonmotorized Transportation is a GRADUAL climate solution. It has a steady, linear impact on the atmosphere. The cumulative effect over time builds as a straight line.

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Caveats

Increases to the modal share of nonmotorized transportation only have the benefits discussed here if they replace travel by car. Replacing public transit travel with travel using nonmotorized transportation will have a much smaller climate benefit. The climate benefit of nonmotorized mobility will also diminish if the average emissions of the global car fleet shrink, for example, due to the wider adoption of electric vehicles. 

There are also uncertainties around trip length. A small number of long trips taken by car will not be replaceable by nonmotorized transportation. Replacing the average trip by car with cycling or pedestrian travel will, in many cases, require that trip to be shortened (for example, by placing businesses closer to people’s homes). If this is not possible, increased adoption of nonmotorized transportation will apply to only some trips, reducing the impact on both emissions and costs.

Weather and climate pose significant challenges and risks for nonmotorized transportation. Extreme heat or cold, wind, rain, or storms can make people reluctant to travel without the protection of a vehicle and, in some cases, can make doing so unsafe (Gössling et al., 2023). This will reduce the adoption of nonmotorized transportation in some places, although it can be mitigated through measures such as providing information and subsidies for proper clothing, removing or grooming snow on bicycle paths, and providing indoor/covered paths that allow pedestrians to travel through a city without exposure to the elements.

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Current Adoption

Analysts most frequently report adoption of nonmotorized transportation as a percentage modal share of all trips taken in a city. Cities around the world have radically different modal shares of bicycle and pedestrian trips. Cities in LMICs often have a high nonmotorized modal share because many people cannot afford cars. Cities in high-income countries are often difficult to navigate without a car, resulting in low modal shares for nonmotorized transportation (Prieto-Curiel & Ospina, 2024). 

Prieto-Curiel and Ospina (2024) estimated that northern North America (the United States and Canada) had the lowest modal share of nonmotorized transportation, at 3.5%. Western Europe reached 29% modal share, while Western and Eastern Africa reached 42.9% and 46%, respectively.

Converting these numbers into vehicle-kilometers traveled on a national level for various countries requires assumptions. A population-weighted average of data available from the United States and several Western European countries finds that people take approximately three 13.2 km trips per day, totaling 39.7 km of daily travel with considerable variation between countries (Christensen & Vázquez, 2013; Department for Transport, 2024; Federal Highway Administration, 2022; Statistics Netherlands, 2024). For example, English people in 2022 traveled an average of 25.5 km/day, while Americans in 2020 traveled 53.5 km/day. The value we use in our analysis comes from a population-weighted average that excludes data from 2020 and 2021 to exclude data skewed by the COVID-19 pandemic. Because the United States has by far the highest population of the countries for which we found data, it skews the average much higher than many of the European countries. World data (ITF, 2021) reports that nonmotorized transportation is 14.4% of all urban pkm.

We assumed that in urban environments, each trip taken by nonmotorized transportation corresponds to one fewer car trip of this average length. This implies that nonmotorized transportation currently shifts approximately 5.6 trillion pkm from cars (Table 3). However, it should be noted that this figure includes low-income countries, where some residents have less access to private vehicles.

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Table 3. Current (2024) adoption level.

Unit: million pkm/yr*

25th percentile 826,600
mean 5,556,000
median (50th percentile) 3,723,000
75th percentile 9,652,000

*These data are extrapolated from a range of individual city estimates from 2010 to 2020 (Prieto-Curiel and Ospina, 2024) and world data (ITF, 2021).

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Adoption Trend

In all cities for which appropriate data exist, nonmotorized transportation showed a growth rate of 0.45% of all passenger trips per year (Prieto-Curiel & Ospina, 2024). This amounts to 49 billion pkm (Table 4) according to our estimation procedure outlined above. In some cities, adoption has grown much more quickly. For example, Hanover, Germany, achieved an average growth of 7.8%/yr in 2011–2017, which amounts to approximately 593 million additional pkm traveled by bicycle every year during that time. However, the rate of adoption is extremely variable. The 25th percentile of estimates shows a global decline in nonmotorized transportation to the tune of 135 billion fewer pkm shifted to nonmotorized modes every year.

Adoption rates of nonmotorized transportation vary widely within a country and between different years within the same city (Prieto-Curiel & Ospina, 2024).

Many people, particularly in LMICs, walk or cycle because they have limited access to a vehicle. When countries become wealthier, travel often shifts from nonmotorized transportation to cars (Seum et al., 2020). If transportation policy in these countries prioritizes car-free mobility, high levels of nonmotorized transportation adoption could potentially be preserved even as living standards increase.

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Table 4. 2023–2024 adoption trend.

Unit: million pkm/yr

25th percentile -134,700
mean 29,570
median (50th percentile) 49,400
75th percentile 296,900
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Adoption Ceiling

We estimated that 20.2% of all trips in cities worldwide, or approximately 5.6 trillion pkm/yr, are traveled by nonmotorized transportation, while 66.2%, or approximately 18.2 trillion pkm/yr, are traveled by fossil fuel–powered car. This suggests that switching all urban trips currently taken by car to nonmotorized transportation would lead to a nonmotorized modal share of 86.4% in cities globally, or 19.7 trillion pkm/yr (Table 5).

This calculation uses the same assumptions discussed under Current Adoption above. In this case, however, our assumption that every nonmotorized trip is shifted from a car trip of the same length requires further justification. We are not assuming that very long car trips, trips on highways, etc., are replaced directly by bicycle or pedestrian trips. Instead, we assume that shorter nonmotorized trips can substitute for longer car trips with appropriate investment in better urban planning and infrastructure. So, for example, a 10 km drive to a large grocery store could be replaced by a 1 km walk to a neighborhood grocery store. 

This would require replanning many cities so they better accommodate shorter trips. It would also require improving options for people with disabilities or those carrying heavy loads. And it would face climatic and topographic constraints. Furthermore, it is unlikely that all car traffic would ever be substituted by any single alternative mode. Other sustainable modes, particularly public transit, are likely to play a role.

It is also possible for rural trips to be undertaken by nonmotorized transportation. Indeed, this is already very common in low-and middle-income countries. However, rural data are sparse, and discerning how many trips could be shifted to nonmotorized travel in these areas is highly speculative. Therefore, we omit rural areas from our analysis.

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Table 5. Adoption ceiling.

Unit: million pkm/yr

median (50th percentile) 19,690,000
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Achievable Adoption

To estimate the upper bound of feasible adoption, we assumed that urban trips taken by fossil fuel–powered cars can be shifted to nonmotorized transportation until the latter accounts for 65% of trips (the current highest modal share of nonmotorized transportation in any city with a population of more than one million) or until car travel decreases to 7% of trips (the current lowest modal share of fossil fuel–powered cars in any city with a population of more than one million). This corresponds to a total achievable nonmotorized transportation modal share of 16.3 trillion pkm/yr (Table 6).

To set the lower bound, we do the same calculation as above, but for each individual region, adding up all the resultant modal shifts to get a global figure. So, for example, every East Asian city might reach the nonmotorized transportation modal share of Singapore (23% of trips), while every northern European city might reach that of Copenhagen, Denmark (41% of trips). This corresponds to a total achievable nonmotorized transportation modal share of 12.4 trillion pkm/yr.

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Table 6. Range of achievable adoption levels.

Unit: million pkm/yr

Current Adoption 5,556,000
Achievable – Low 12,369,000
Achievable – High 16,340,000
Potential Adoption 19,690,000
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If all cycling and pedestrian trips undertaken today would otherwise have happened by car, they are currently displacing approximately 0.6 Gt CO₂‑eq/yr emissions (Table 7). This is an overestimate, however, since this figure includes data from places where most people have low access to cars.

Walking and private bicycles have a different effectiveness than shared bicycles. To calculate the climate impacts of different levels of adoption, we applied the effectiveness in the share of each mode of nonmotorized transportation. Walking and private bicycling are 94.4% of nonmotorized pkm and shared bicycling is 5.3%. This gives nonmotorized transportation effectiveness at reducing emissions 115.6 t CO₂‑eq /million pkm.

On the lower end, if every city achieved a pedestrian and cycling modal share equivalent to the least-motorized city in its region, it would save 1.4 Gt CO₂‑eq/yr. On the higher end, if every city shifted enough passenger car traffic to achieve a car modal share as low as Hong Kong, China, it would save 1.9 Gt CO₂‑eq/yr. If all trips taken by car were shifted onto nonmotorized transportation (an unrealistic scenario), it would save 2.3 Gt CO₂‑eq/yr.

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Table 7. Climate impact at different levels of adoption.

Unit: Gt CO₂‑eq/yr, 100-yr basis

Current Adoption 0.642
Achievable – Low 1.430
Achievable – High 1.889
Adoption Ceiling 2.276
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Additional Benefits

Health and Air Quality

Air pollution kills approximately 7 million people yearly (Roser, 2024). By reducing vehicle emissions, nonmotorized transportation can alleviate related air pollution (Mailloux et al., 2021) and thereby reduce premature deaths. For example, cutting U.S. transportation emissions by 75% by 2030 could prevent 14,000 premature deaths annually due to decreased exposure to PM2.5 and ozone (Shindell et al., 2016). 

Nonmotorized transportation has other health and safety benefits (Blondiau et al., 2016; European Commission, 2019; Glazener & Khreis, 2019; Gössling et al., 2023; Mueller et al., 2015; State of Colorado, 2016; Xia et al., 2013). Switching from driving to walking or cycling boosts health by promoting physical activity and decreasing risks of cardiovascular issues, diabetes, and mental disorders (Mailloux et al., 2021).

Noise pollution from motorized vehicles has significant impacts on cardiovascular health, mental health, and sleep disturbances, contributing to 1.6 million lost healthy life years in 2004 and up to 1,100 deaths attributable to hypertension in Europe in 2024 (Staatsen et al., 2004; Munzel et al., 2024). Enhancing nonmotorized transportation can reduce the health impacts of traffic noise (de Nazelle et al., 2011).

Finally, nonmotorized transportation improves quality of life. It increases opportunities for human connection, integrates physical activity and fun into daily commutes, and increases the autonomy of less mobile groups such as children and elders. Cities with high modal shares for nonmotorized transportation generally have high quality of life (Adamos et al., 2020; Günther & Krems, 2022; Glazener and Khreis, 2019).

The use of nonmotorized transportation can reduce car crashes, which kill around 1.2 million people annually (WHO, 2023).

Income and Work

Nonmotorized transportation infrastructure tends to be good for local businesses. Cyclists and pedestrians are more likely to stop at businesses they pass and therefore spend more money locally, creating more jobs (Volker & Handy, 2021). 

Nature Protection

In 2011, roads and associated infrastructure accounted for 10–30% of land in residential areas and 50–70% of land in commercial areas (Litman, 2011). Transforming these lands into green spaces could provide additional habitats and reduce biodiversity loss while increasing the protection of land, soil, and water resources (European Commission, 2019).

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Risks

Some literature suggested that nonmotorized transportation can lead to gentrification because bike lanes and pleasant walkable streets can increase property values, driving people who used to live in a neighborhood into other places that might still be car-dependent (Flanagan et al., 2016). This risk can be addressed by ensuring that nonmotorized transportation infrastructure is built in an equitable way, connecting different neighborhoods regardless of their social and economic status. Increasing the number of neighborhoods accessible without a car will mean that people do not have to pay a premium to live in those neighborhoods. This will avoid making accessibility without a car a privilege that only the wealthy can afford.

Cycling in a city with lots of traffic and poor cycling infrastructure puts cyclists at risk of injury from collisions with cars. This risk, however, comes mainly from the presence of cars on roads. Reducing the number of cars on the road by shifting trips to other modes can improve safety for cyclists and pedestrians (Bopp et al., 2018).

The positive impacts that nonmotorized transportation have on traffic congestion could be self-defeating if not managed well. This is because less congestion will make driving more appealing, which can, in turn, lead to additional induced demand, increasing car use and congestion (Hymel et al., 2010).

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Interactions with Other Solutions

Reinforcing

Nonmotorized transportation can help passengers access public transit systems, train stations, and carpool pickup points. This is important because research suggests that the key to a low-carbon mobility system is to reduce the need for people to own cars (Van Acker & Witlox, 2010).

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Electric bicycles use the same infrastructure as nonmotorized transportation – especially conventional bicycles. Building bike lanes, bike paths, mixed-use paths, and similar infrastructure for cyclists and pedestrians can also help with the uptake of electric bicycles. This is even more true for shared electric bicycles, which can and often do use the same sharing systems as shared conventional bicycles.

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One way to encourage the adoption of electric cars is through electric car–sharing services, in which people can access a communal electric car when they need it. This has the additional benefit of reducing the need for car ownership, which is closely correlated with car use (Van Acker and Witlox, 2010). Good nonmotorized transportation infrastructure can make it easier for users of these services to access shared vehicles parked at central locations.

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Nonmotorized transportation requires a lot less space than cars. Some of this space could be reallocated to ecosystem conservation and other land-based methods of GHG sequestration. In 2011, roads and parking accounted for 10–30% of land in residential areas and 50–70% of land in commercial areas (Litman, 2011). Transforming 35% of the land area of European cities alone into green spaces could sequester an additional 26 Mt CO₂‑eq/yr. Globally, this kind of effort could sequester 0.1–0.3 Gt CO₂‑eq/yr (Rodriguez Mendez et al., 2024).

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Competing

Electric cars, hybrid cars, and nonmotorized transportation compete for the same pool of total pkm. Increased use of nonmotorized transportation could reduce kilometers traveled using electric cars. 

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Consensus

Consensus of effectiveness in decarbonizing the transport sector: High

The large reductions in emissions that come from shifting passenger transportation from fossil fuel-powered cars to nonmotorized modes are not controversial. There is some disagreement, however, over how many pkm traveled by car can be realistically shifted to nonmotorized transportation.

Brand et al. (2021) compared the GHG emissions of active transportation with those of cars. They concluded that “locking in, investing in and promoting active travel should be a cornerstone of sustainability strategies, policies and planning.”

The Intergovernmental Panel on Climate Change (IPCC, 2023) sixth assessment report mentioned nonmotorized transportation as a solution in its transportation chapter. The authors expressed high confidence in the potential of these transportation modes to reduce emissions and recommended policy and infrastructural measures to support them.

Litman’s (2024) study of the costs and benefits of active transportation summarized the direct financial costs as well as externalities associated with pedestrian and bicycle travel compared with travel by fossil fuel–powered car. Litman noted that “active transport can provide relatively large energy savings if it substitutes for short urban trips that have high emission rates per mile due to cold starts (engines are inefficient during the first few minutes of operation) and congestion. As a result, each 1% shift from automobile to active travel typically reduces fuel consumption 2–4%.”

This research is, unfortunately, heavily biased toward richer countries, especially in Europe and North America, even though nonmotorized transportation plays a very important role in low- and middle-income countries (LMICs). The research on this topic is also biased toward cities, even though nonmotorized transportation can be a valuable means of mobility in rural areas. 

The results presented in this document summarize findings from 19 reviews and meta-analyses and 14 original studies reflecting current evidence from 84 countries, primarily the United States, the United Kingdom, and the European Union. We recognize this limited geographic scope creates bias, and hope this work inspires research and data sharing on this topic in underrepresented regions.

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Dashboard

Solution Basics

million passenger kilometers (million pkm)

t CO₂-eq (100-yr)/unit
099.33115.6
units/yr
Current 5.556×10⁶ 01.236×10⁷1.634×10⁷
Achievable (Low to High)

Climate Impact

Gt CO₂-eq (100-yr)/yr
Current 0.642 1.431.889
US$ per t CO₂-eq
-1,771
Gradual

CO₂, CH₄, N₂O, BC

Trade-offs

Production of equipment (such as bicycles) and infrastructure (such as sidewalks) creates some emissions, but these are small when divided by the total distance traveled by pedestrians and cyclists. On a per-pkm basis, this makes little difference in the emissions saved by nonmotorized transportation. 

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% population
0–20
20–40
40–60
60–80
> 80

Percentage of city population living near protected bikeways, 2023

Proximity to related infrastructure, such as protected bikeways, facilitates the safe and convenient use of nonmotorized modes of transportation.

Reich, D. T. & Braga, K. (2024). Atlas of Sustainable City Transport [Data set]. Institute for Transportation and Development Policy. Retrieved June 2, 2025 from atlas.itdp.org

% population
0–20
20–40
40–60
60–80
> 80

Percentage of city population living near protected bikeways, 2023

Proximity to related infrastructure, such as protected bikeways, facilitates the safe and convenient use of nonmotorized modes of transportation.

Reich, D. T. & Braga, K. (2024). Atlas of Sustainable City Transport [Data set]. Institute for Transportation and Development Policy. Retrieved June 2, 2025 from atlas.itdp.org

Maps Introduction

Nonmotorized transportation effectiveness is high across all geographic regions, though the built environment, safety, and socio-cultural norms heavily shape its adoption and impact. Key determinants of effectiveness include the extent of safe and connected infrastructure (e.g., sidewalks, bike lanes, protected intersections), land-use patterns supporting short trips, and public policies prioritizing nonmotorized transportation.

Overall, effectiveness depends on adoption. In many cities across Europe and Asia, walking and cycling remain integral to daily travel. Cities like Amsterdam, Copenhagen, and Tokyo have successfully integrated nonmotorized modes into their broader transport systems through dedicated infrastructure and supportive urban design. In contrast, cities in North America, Sub-Saharan Africa, and parts of Latin America often lack safe, accessible infrastructure, which limits adoption.

Socioeconomic factors, including income levels, urban design, and perceptions of status, also influence the adoption of nonmotorized transport. In wealthier regions, cycling may be viewed as a lifestyle choice or an environmental statement, whereas in lower-income settings, it may be perceived as a necessity or even a sign of economic disadvantage, influencing user behavior and policy support (Seum et al., 2020).

Although shared bicycles have a lower effectiveness than walking or private bicycles, they are much more effective than cars. Increasing the number of shared bicycle systems in any geographic area can increase adoption and, therefore, make them more effective. This is particularly effective in lower-income areas where owning a private bicycle might be cost-prohibitive (Litman, 2024). Increasing shared systems in less urban and more suburban areas can be more effective, as they often replace trips made by car (Brand et al., 2021).

Nonmotorized modes are generally resilient and functional in a wide range of climates. Extreme weather conditions, including high heat, heavy rainfall, or snow, can reduce walking and cycling, although these can be mitigated through appropriate infrastructure (e.g., shaded or covered walkways, snow clearing, bike shelters).

Action Word
Improve
Solution Title
Nonmotorized Transportation
Classification
Highly Recommended
Lawmakers and Policymakers
  • Use nonmotorized transportation.
  • Reduce the associated time, distance, risk, and risk perception of nonmotorized transportation.
  • Improve infrastructure such as sidewalks, footpaths, and bike lanes.
  • Implement traffic-calming methods such as speed bumps.
  • Increase residential and commercial density.
  • Use a citizen-centered approach when designing infrastructure.
  • Enact infrastructure standards for nonmotorized transportation, such as curb ramp designs, and train contractors to implement them.
  • Establish public bike-sharing programs.
  • Create dedicated coordinating bodies across government agencies, businesses, and the public to develop nonmotorized infrastructure.
  • Disincentivize car ownership through reduced access, increases in parking fares, taxes, or other means. 

Further information:

Practitioners
  • Use nonmotorized transportation.
  • Share your experiences, tips, and reasons for choosing your modes of transportation.
  • Participate in local bike groups, public events, and volunteer opportunities.
  • Advocate to local officials for infrastructure improvements and note specific locations for improvements.
  • Encourage local businesses to create employee incentives.
  • Create “bike buses” or “walking buses” for the community and local schools.

Further information:

Business Leaders
  • Use nonmotorized transportation.
  • Ensure your business is accessible via nonmotorized transportation.
  • Advocate for better infrastructure for nonmotorized transportation.
  • Educate customers about the local infrastructure.
  • Partner with other businesses to encourage employees to cycle or walk.
  • Encourage employees to walk or cycle to and from work as their circumstances allow.
  • Create educational materials for employees on commuting best practices.
  • Offer employees pre-tax commuter benefits to include reimbursement for nonmotorized travel expenses.
  • Organize staff bike rides to increase familiarity and comfort with bicycling.
  • Install adequate bike storage, such as locking posts.
  • Emphasize walking and biking as part of company-wide sustainability initiatives and communicate how walking and biking support broader GHG emission reduction efforts.

Further information:

Nonprofit Leaders
  • Use nonmotorized transportation.
  • Ensure your office is accessible to nonmotorized transportation.
  • Advocate for infrastructure improvements and note specific locations where improvements can be made.
  • Encourage local businesses to create employee incentives.
  • Create “bike buses” or “walking buses” for the community and/or local schools.
  • Offer free classes on subjects such as bike maintenance, local bike routes, or what to know before purchasing a bike.
  • Host or support community participation in local infrastructure design.
  • Join public-private partnerships to encourage biking and walking, emphasizing the health and savings benefits.

Further information:

Investors
  • Use nonmotorized transportation.
  • Deploy capital to efforts that improve bicycle and walking comfort, convenience, access, and safety.
  • Invest in public or private bike-sharing systems.
  • Invest in local supply chains for bicycles and other forms of nonmotorized transportation.
  • Seek investment opportunities that reduce material and maintenance costs for bicycles.
  • Finance bicycle purchases via low-interest loans.
  • Consider investments in nonmotorized transportation start-ups.

Further information:

Philanthropists and International Aid Agencies
  • Use nonmotorized transportation.
  • Award grants to local organizations advocating for improved walking and bicycle infrastructure.
  • Build capacity for walking and bicycle infrastructure design and construction.
  • Support organizations that distribute, refurbish, and/or donate bikes in your community.
  • Facilitate access to bicycle maintenance and supplies.
  • Host or support community education or participation efforts.
  • Donate fixtures such as street lights, guardrails, and road signs.
  • Educate the public and policymakers on the benefits and best practices of nonmotorized transportation.

Further information:

Thought Leaders
  • Use nonmotorized transportation.
  • Focus messages on key decision factors for nonmotorized commuters, such as the associated health benefits and importance of fitness, climate and environmental benefits, weather forecasts, and traffic information.
  • Highlight principles of safe urban design and point out dangerous areas.
  • Share information on local bike and walking routes, general bike maintenance tips, items to consider when purchasing a bike, and related educational information.
  • Collaborate with schools on bicycle instruction, including safe riding habits and maintenance.

Further information:

Technologists and Researchers
  • Use nonmotorized transportation.
  • Examine and improve elements of infrastructure design.
  • Improve circularity, repairability, and ease of disassembly for bikes.
  • Increase the physical carrying capacities (storage) for walkers and bicyclists to facilitate shopping and transporting children, pets, and materials.
  • Identify and encourage the deployment of messaging that enhances nonmotorized transportation use.

Further information:

Communities, Households, and Individuals
  • Use nonmotorized transportation.
  • Share your experiences, tips, and reasons for choosing nonmotorized transportation.
  • Participate in local bike groups, public events, and volunteer opportunities.
  • Advocate to local officials for infrastructure improvements and note specific locations where improvements can be made.
  • Encourage local businesses to create employee incentives for using nonmotorized transportation.
  • Create “bike buses” or “walking buses” for the community and local schools.

Further information:

Sources
Evidence Base

Consensus of effectiveness in decarbonizing the transport sector: High

The large reductions in emissions that come from shifting passenger transportation from fossil fuel-powered cars to nonmotorized modes are not controversial. There is some disagreement, however, over how many pkm traveled by car can be realistically shifted to nonmotorized transportation.

Brand et al. (2021) compared the GHG emissions of active transportation with those of cars. They concluded that “locking in, investing in and promoting active travel should be a cornerstone of sustainability strategies, policies and planning.”

The Intergovernmental Panel on Climate Change (IPCC, 2023) sixth assessment report mentioned nonmotorized transportation as a solution in its transportation chapter. The authors expressed high confidence in the potential of these transportation modes to reduce emissions and recommended policy and infrastructural measures to support them.

Litman’s (2024) study of the costs and benefits of active transportation summarized the direct financial costs as well as externalities associated with pedestrian and bicycle travel compared with travel by fossil fuel–powered car. Litman noted that “active transport can provide relatively large energy savings if it substitutes for short urban trips that have high emission rates per mile due to cold starts (engines are inefficient during the first few minutes of operation) and congestion. As a result, each 1% shift from automobile to active travel typically reduces fuel consumption 2–4%.”

This research is, unfortunately, heavily biased toward richer countries, especially in Europe and North America, even though nonmotorized transportation plays a very important role in low- and middle-income countries (LMICs). The research on this topic is also biased toward cities, even though nonmotorized transportation can be a valuable means of mobility in rural areas. 

The results presented in this document summarize findings from 19 reviews and meta-analyses and 14 original studies reflecting current evidence from 84 countries, primarily the United States, the United Kingdom, and the European Union. We recognize this limited geographic scope creates bias, and hope this work inspires research and data sharing on this topic in underrepresented regions.

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Updated Date

Mobilize Hybrid Cars

Submitted by Drawdown Admin on
Sector
Transportation
Mode
Cut Emissions
Cluster
Enhance Efficiency
Image
Start button on a hybrid vehicle
Coming Soon
Off
Summary

The Mobilize Hybrid Cars solution entails shifting trips from fossil fuel–powered internal combustion engine (ICE) cars to more efficient, lower emitting hybrid cars. Hybrid cars include hybrid electric cars (HEVs) and plug-in hybrid electric cars (PHEVs). They are four-wheeled passenger cars that combine an ICE with an electric motor and battery to improve fuel efficiency and reduce emissions. This definition includes hybrid sedans, sport utility vehicles (SUVs), and pickup trucks, but excludes fully electric cars, two-wheeled vehicles, and hybrid commercial or freight vehicles, such as hybrid buses and delivery trucks. Hybrid cars are a transitional climate solution because they are more efficient and produce fewer emissions per distance traveled than do fossil fuel–powered ICE cars but still rely on fossil fuel combustion.

Income & work,Health
Air quality
Description for Social and Search
Mobilize Hybrid Cars is a Highly Recommended climate solution. By combining internal combustion engines with electric motors, hybrids reduce fuel use and air pollution.
Overview

Hybrid cars reduce fuel consumption and tailpipe emissions by relying on electric propulsion for part of their operation. There are currently more than 45 million hybrids making up 2.2% of the more than two billion global car stock. HEVs provide the same functionality as fossil fuel–powered ICE cars, but combine an ICE with an electric motor and battery to improve fuel efficiency. Unlike electric cars, HEVs do not require external charging; instead, they recharge their battery using regenerative braking and energy from the engine. This allows them to use electric power at low speeds and in stop-and-go traffic, reducing fuel consumption and emissions compared to traditional gasoline or diesel cars. PHEVs work similarly but have larger batteries that can be charged using the electricity grid. This enables them to operate in full-electric mode for a limited distance before switching to hybrid mode when the battery is depleted.

Hybrid cars typically offer better acceleration than their purely fossil fuel–powered ICE counterparts, especially at lower speeds. This is because electric motors deliver instant torque, allowing hybrids to respond quickly when accelerating from a stop. PHEVs tend to have stronger electric motors and thus better acceleration. The high torque at low speeds eliminates the need for inefficient gear changes and allows near-constant operation at optimal conditions because the ICE is usually engaged at efficient conditions. This improves the real-world fuel economy 39–58% compared to fossil fuel–powered ICE cars of similar size (Zhang et al., 2025).

While hybrid cars reduce fuel consumption and tailpipe emissions by relying on electric propulsion for part of their operation, their overall emissions depend on how much they use the ICE versus the electric motor, and, for PHEVs, on the emissions intensity of the electricity source used for charging. PHEVs can offer greater potential for emission reductions if charged from low-carbon electricity sources. If driven primarily in electric mode, PHEVs can significantly reduce GHG emissions compared to fossil fuel–powered ICE cars, but if the battery is not regularly charged, their fuel consumption may be similar to or even higher than standard HEVs (Dornoff, 2021; Plötz et al., 2020).

Hybrid technologies also improve car efficiency by reducing energy losses. First, both HEVs and PHEVs recover energy through regenerative braking, converting kinetic energy into electricity and storing it in the battery (Yang et al., 2024). Second, their electric powertrains are more efficient than those of traditional ICEs, particularly in urban driving conditions where frequent stops and starts are common (Verma et al., 2022). These advantages contribute to lower fuel consumption and emissions compared to fossil fuel–powered ICE cars. However, the environmental benefits of hybrids depend on driving patterns, battery charging habits, and the carbon intensity of the electricity grid used to charge PHEVs.

Hybrid cars reduce emissions of CO₂, methane, and nitrous oxide to the atmosphere by increasing fuel efficiency compared to fossil fuel–powered ICE cars, which emit these gases from their tailpipes. Because they are typically fueled by gasoline, hybrid cars produce more methane than any diesel-fueled cars they might be replacing. As a result, their 20-yr effectiveness at addressing climate change is lower than their 100-yr effectiveness. 

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Bell-Pasht, A. (2024). Combined energy burdens: Estimating total home and transportation energy burdens [Topic brief]. American Council for an Energy-Efficient Economy. Link to source: https://www.aceee.org/topic-brief/2024/05/combined-energy-burdens-estimating-total-home-and-transportation-energy-burdens

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Castelvecchi, D. (2021, August 17). Electric cars and batteries: How will the world produce enough? [News feature]. Nature, 596(7872), 336–339. Link to source: https://doi.org/10.1038/d41586-021-02222-1

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Dornoff, J. (2021). Plug-in hybrid vehicle CO2 emissions: How they are affected by ambient conditions and driver mode selection [White paper]. International Council on Clean Transportation. Link to source: https://theicct.org/publication/plug-in-hybrid-vehicle-co2-emissions-how-they-are-affected-by-ambient-conditions-and-driver-mode-selection/

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Isenstadt, A., & Slowik, P. (2025). Hybrid vehicle technology developments and opportunities in the 2025–2035 time frame [Working paper]. International Council on Clean Transportation. Link to source: https://theicct.org/publication/hybrid-vehicle-technology-developments-and-opportunities-in-the-2025-2035-time-frame-feb25/

Jones, S. J. (2019). If electric cars are the answer, what was the question? British Medical Bulletin, 129(1), 13–23. Link to source: https://doi.org/10.1093/bmb/ldy044

Kerr, G. H., Goldberg, D. L., & Anenberg, S. C. (2021). COVID-19 pandemic reveals persistent disparities in nitrogen dioxide pollution. Proceedings of the National Academy of Sciences, 118(30), Article e2022409118. Link to source: https://doi.org/10.1073/pnas.2022409118

Kittner, N., Tsiropoulos, I., Tarvydas, D., Schmidt, O., Staffell, I., & Kammen, D. M. (2020). Electric vehicles. In M. Junginger & A. Louwen (Eds.), Technological learning in the transition to a low‑carbon energy system: Conceptual issues, empirical findings, and use in energy modeling (pp. 145–163). Academic Press. Link to source: https://doi.org/10.1016/B978-0-12-818762-3.00009-1

Larson, E., Greig, C., Jenkins, J., Mayfield, E., Pascale, A., Zhang, C., Drossman, J., Williams, R., Pacala, S., Socolow, R., Baik, E., Birdsey, R., Duke, R., Jones, R., Haley, B., Leslie, E., Paustain, K., & Swan, A. (2020). Net-zero America: Potential pathways, infrastructure, and impacts [Interim report]. Princeton University, Andlinger Center for Energy and the Environment. Link to source: https://netzeroamerica.princeton.edu/the-report

Lutsey, N., Cui, H., & Yu, R. (2021). Evaluating electric vehicle costs and benefits in China in the 2020–2035 time frame [White paper]. International Council on Clean Transportation. Link to source: https://theicct.org/publication/evaluating-electric-vehicle-costs-and-benefits-in-china-in-the-2020-2035-time-frame/

Menes, M. (2021). Two decades of hybrid electric vehicle market. Journal of Civil Engineering and Transport, 3(1), 29–37. Link to source: https://doi.org/10.24136/tren.2021.003

Milovanoff, A., Posen, I. D., & MacLean, H. L. (2020). Electrification of light-duty vehicle fleet alone will not meet mitigation targets. Nature Climate Change, 10(12), 1102–1107. Link to source: https://doi.org/10.1038/s41558-020-00921-7

Mittal, V., & Shah, R. (2024). Modeling and comparing the total cost of ownership of passenger automobiles with conventional, electric, and hybrid powertrains. SAE International Journal of Sustainable Transportation, Energy, Environment, & Policy, 5(2), 179–192. Link to source: https://doi.org/10.4271/13-05-02-0013

Mustapa, S. I., Ayodele, B. V., Mohamad Ishak, W. W., & Ayodele, F. O. (2020). Evaluation of cost competitiveness of electric vehicles in Malaysia using life cycle cost analysis approach. Sustainability, 12(13), Article 5303. Link to source: https://doi.org/10.3390/su12135303

Ouyang, D., Zhou, S., & Ou, X. (2021). The total cost of electric vehicle ownership: A consumer-oriented study of China’s post-subsidy era. Energy Policy, 149, Article 112023. Link to source: https://doi.org/10.1016/j.enpol.2020.112023

Pennington, A. F., Cornwell, C. R., Sircar, K. D., & Mirabelli, M. C. (2024). Electric vehicles and health: A scoping review. Environmental Research, 251, Article 118697. Link to source: https://doi.org/10.1016/j.envres.2024.118697

Peters, D. R., Schnell, J. L., Kinney, P. L., Naik, V., & Horton, D. E. (2020). Public health and climate benefits and trade‐offs of U.S. vehicle electrification. GeoHealth, 4(10), Article e2020GH000275. Link to source: https://doi.org/10.1029/2020GH000275

Petrauskienė, K., Galinis, A., Kliaugaitė, D., & Dvarionienė, J. (2021). Comparative environmental life cycle and cost assessment of electric, hybrid, and conventional vehicles in Lithuania. Sustainability, 13(2), Article 957. Link to source: https://doi.org/10.3390/su13020957

Plötz, P., Moll, C., Li, Y., Bieker, G., & Mock, P. (2020). Real-world usage of plug-in hybrid electric vehicles: Fuel consumption, electric driving, and CO2 emissions [White paper]. International Council on Clean Transportation. Link to source: https://theicct.org/publication/real-world-usage-of-plug-in-hybrid-electric-vehicles-fuel-consumption-electric-driving-and-co2-emissions

Requia, W. J., Mohamed, M., Higgins, C. D., Arain, A., & Ferguson, M. (2018). How clean are electric vehicles? Evidence-based review of the effects of electric mobility on air pollutants, greenhouse gas emissions and human health. Atmospheric Environment, 185, 64–77. Link to source: https://doi.org/10.1016/j.atmosenv.2018.04.040

Roberts, C. (2022). Easy street for low-carbon mobility? The political economy of mass electric car adoption. In G. Parkhurst & W. Clayton (Eds.), Electrifying mobility: Realising a sustainable future for the car (Vol. 15, pp. 13–31). Emerald Publishing Limited. Link to source: https://doi.org/10.1108/S2044-994120220000015004

Romm, J. J., & Frank, A. A. (2006, April). Hybrid vehicles gain traction. Scientific American, 294(4), 72–79. https://doi.org/10.1038/scientificamerican0406-72

Sovacool, B. K. (2019). The precarious political economy of cobalt: Balancing prosperity, poverty, and brutality in artisanal and industrial mining in the Democratic Republic of the Congo. The Extractive Industries and Society, 6(3), 915–939. Link to source: https://doi.org/10.1016/j.exis.2019.05.018

Suttakul, P., Wongsapai, W., Fongsamootr, T., Mona, Y., & Poolsawat, K. (2022). Total cost of ownership of internal combustion engine and electric vehicles: A real-world comparison for the case of Thailand. Energy Reports, 8, 545–553. Link to source: https://doi.org/10.1016/j.egyr.2022.05.213

Vega-Perkins, J., Newell, J. P., & Keoleian, G. (2023). Mapping electric vehicle impacts: Greenhouse gas emissions, fuel costs, and energy justice in the United States. Environmental Research Letters, 18(1), Article 014027. Link to source: https://doi.org/10.1088/1748-9326/aca4e6

Verma, S., Dwivedi, G., & Verma, P. (2022). Life cycle assessment of electric vehicles in comparison to combustion engine vehicles: A review. Materials Today: Proceedings, 49, 217–222. Link to source: https://doi.org/10.1016/j.matpr.2021.01.666

Weiss, M., Zerfass, A., & Helmers, E. (2019). Fully electric and plug-in hybrid cars - An analysis of learning rates, user costs, and costs for mitigating CO2 and air pollutant emissions. Journal of Cleaner Production, 212, 1478–1489. Link to source: https://doi.org/10.1016/j.jclepro.2018.12.019

World Health Organization. (2022). Number of registered vehicles [Data set]. The Global Health Observatory. https://www.who.int/data/gho/data/indicators/indicator-details/GHO/number-of-registered-vehicles

Yang, C., Sun, T., Wang, W., Li, Y., Zhang, Y., & Zha, M. (2024). Regenerative braking system development and perspectives for electric vehicles: An overview. Renewable and Sustainable Energy Reviews, 198, Article 114389. Link to source: https://doi.org/10.1016/j.rser.2024.114389

Zhang, Y., Fan, P., Lu, H., & Song, G. (2025). Fuel consumption of hybrid electric vehicles under real-world road and temperature conditions. Transportation Research Part D: Transport and Environment, 142, Article 104691. Link to source: https://doi.org/10.1016/j.trd.2025.104691 

Credits

Lead Fellow

  • Heather Jones, Ph.D.

  • Cameron Roberts, Ph.D.

Contributors

  • Ruthie Burrows, Ph.D.

  • James Gerber, Ph.D.

  • Yusuf Jameel, Ph.D.

  • Daniel Jasper

  • Alex Sweeney

Internal Reviewers

  • Aiyana Bodi

  • Hannah Henkin

  • Zoltan Nagy, Ph.D. 

  • Ted Otte

  • Amanda D. Smith, Ph.D.

  • Christina Swanson, Ph.D.

Effectiveness

Each million pkm shifted from fossil fuel–powered cars to hybrid cars saves 27.11 t CO₂‑eq on a 100-yr basis (26.94 t CO₂‑eq on a 20-yr basis, Table 1). Fossil fuel–powered cars emit 115.3 t CO₂‑eq/million pkm on a 100-yr basis (116.4 t CO₂‑eq/million pkm on a 20-yr basis). The emissions from fossil fuel–powered ICE cars are calculated from the current global fleet mix which is mostly gasoline and diesel powered cars. PHEVs have lower emissions in countries with large shares of renewable, nuclear, or hydropower generation in their electricity grids (International Transport Forum, 2020; Verma et al., 2022).

We found this by collecting data on fuel consumption per kilometer for a range of HEV and PHEV models (International Energy Agency [IEA], 2021; International Transport Forum, 2020) and multiplying it by the emissions intensity of the fuel the vehicle uses (weighting PHEVs for percentage traveled using fuel). Simultaneously, we collected data on electricity consumption for a range of PHEV models (IEA, 2021; International Transport Forum, 2020), and multiplied them by the global average emissions per kWh of electricity generation. This was then weighted by the share of HEVs (73.4%) and PHEVs (26.6%) of the global hybrid car stock.

The amount of emissions savings for PHEVs depends on how often they are charged, the distance traveled using the electric motor, and the emissions intensity of the electrical grid from which they are charged. Hybrid cars today are disproportionately used in high and upper-middle income countries, where electricity grids emit less than the global average per unit of electricity generated (IEA, 2024). HEVs and PHEVs benefit from braking so are more efficient (relative to fossil fuel–powered ICE cars) in urban areas.

Hybrid cars have higher embodied emissions than fossil fuel–powered ICE cars due to the presence of both an ICE and electric motor with a battery that has a GHG-intensive manufacturing process. This gives them a carbon payback period of 2.6 to under 16 years (Alberini et al., 2019; Duncan et al., 2019) for HEVs and as low as one year for PHEVs (Fulton, 2020). Embodied emissions are outside the scope of this assessment. 

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Table 1. Effectiveness at reducing emissions.

Unit: t CO₂‑eq/million pkm, 100-yr basis

25th percentile 19.51
mean 22.36
median (50th percentile) 27.11
75th percentile 65.85
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Cost

Hybrid cars cost on average US$0.01 more per pkm (US$7,200/million pkm) than fossil fuel–powered ICE cars, including purchase price, financing, fuel and electricity costs, and maintenance costs. This is based on a population-weighted average of the cost differential between hybrid and fossil fuel–powered ICE cars in the EU and 11 other countries: Argentina, China, Czechia, India, Indonesia, Lithuania, Malaysia, South Africa, Thailand, Ukraine, and the United States (BEUC, 2021; Furch et al., 2022; IEA, 2022; Isenstadt & Slowik, 2025; Lutsey et al., 2021; Mittal & Shah, 2024; Mustapa et al., 2020; Ouyang et al., 2021; Petrauskienė et al., 2021; Suttakul et al., 2022). The hybrid cost is weighted by the share of car stock of HEVs and PHEVs. 

While this analysis found that hybrid cars are slightly more expensive than fossil fuel–powered ICE cars almost everywhere, the margin is often quite small and hybrids are less expensive in China, Czechia, India, Thailand, and the United States.

This amounts to a cost of US$264/t CO₂‑eq on a 100-yr basis (US$266/t CO₂‑eq avoided emissions on a 20-yr basis, Table 2).

This analysis did not include costs that are the same for both hybrid and fossil fuel–powered ICE cars, including taxes, insurance costs, public costs of building road infrastructure, etc.

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Table 2. Cost per unit of climate impact.

Unit: 2023 US$/t CO₂‑eq , 100-yr basis

median 264
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Learning Curve

Hybrid car prices are declining. For every doubling in hybrid car production, costs decline in accordance with the learning rate of approximately 10% (Table 3).

The learning curve for hybrids is expected to continue its historical trend of 6–17% declines in production costs with each generation (Kittner et al., 2020; Ouyang et al., 2021; Weiss et al., 2019). For hybrid cars, production costs are driven more by the integration of electric and internal combustion powertrain components than by advancements in battery technology. Because they still rely on ICEs, hybrids do not experience the same rapid cost declines from battery improvements as fully electric cars. Instead, their cost reductions stem from manufacturing efficiencies, economies of scale, and advancements in hybrid powertrain efficiency and electric components (Weiss et al., 2019).

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Table 3. Learning rate: drop in cost per doubling of the installed solution base %.

Unit: %

25th percentile 8.00
mean 11.00
median (50th percentile) 10.00
75th percentile 13.50
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Speed of Action

Speed of action refers to how quickly a climate solution physically affects the atmosphere after it is deployed. This is different from speed of deployment, which is the pace at which solutions are adopted. 

At Project Drawdown, we define the speed of action for each climate solution as emergency brake, gradual, or delayed.

Mobilize Hybrid Cars is a GRADUAL climate solution. It has a steady, linear impact on the atmosphere. The cumulative effect over time builds as a straight line.

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Caveats

Hybrid cars are often considered a transitional technology for climate change mitigation. While they offer immediate reductions in fuel consumption and emissions compared to fossil fuel–powered ICE cars as the world transitions to fully electric transportation, hybrids still rely on the combustion of fossil fuels. The Mobilize Hybrid Cars solution is a move toward lower emissions – not zero emissions. By combining electric and gasoline powertrains, hybrids improve efficiency and reduce GHG emissions without requiring extensive charging infrastructure, making them a practical short-term solution (IEA, 2021). However, as battery costs decline, renewable energy expands, and charging networks improve, fully electric cars (EVs) are expected to replace hybrids as the dominant low-emission transportation option (Plӧtz et al., 2020).

The effectiveness of hybrid cars in reducing fuel consumption and emissions depends significantly on their ability to use electric power, which is influenced by charging habits and regenerative braking efficiency. PHEVs achieve the greatest fuel savings and emissions reductions when they are regularly charged from a low-emissions-intensity electricity grid because this maximizes their electric driving capability and minimizes reliance on the ICE. However, studies show that real-world charging behaviors vary, with some PHEV users failing to charge frequently, leading to higher-than-expected fuel consumption. Regenerative braking also plays a crucial role because it recaptures kinetic energy during deceleration and converts it into electricity to recharge the battery, improving overall efficiency. The extent of these benefits depends on driving conditions, with stop-and-go urban traffic allowing for more energy recovery than highway driving, where regenerative braking opportunities are limited (Plötz et al., 2020).

Hybrid car adoption faces a major obstacle in the form of constraints on battery production. While electric car battery production is being aggressively upscaled (IEA, 2024), building enough batteries to build enough cars to replace a significant fraction of fossil fuel–powered ICE cars is an enormous challenge. This will likely slow down a transition to hybrids, even if consumer demand is high (Milovanoff et al., 2020). This suggests that EV batteries should be prioritized for users whose transport needs are harder to serve with other forms of low-emissions transportation (such as nonmotorized transportation, public transit, etc.). This could include emergency vehicles, commercial vehicles, and vehicles for people who live in rural areas or have disabilities. 

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Current Adoption

Approximately 12 million PHEVs (IEA, 2024) and more than 33 million HEVs (IEA, 2023) are in use worldwide. This corresponds to about 2.2% of the total car stock of 2,022,057,847 (World Health Organization [WHO], 2022) and means that hybrid cars worldwide travel about 1.3 trillion pkm/yr. We assumed this travel would occur in a fossil fuel–powered ICE car if the car’s occupants did not use a hybrid car. Adoption is much higher in some countries, such as Japan, where the global hybrid car stock share was 20–30% in 2023.

To convert this number into pkm traveled by hybrid car, we need to determine the average passenger-distance that each passenger car travels per year. Using population-weighted data from several different countries, the average car carries 1.5 people and travels about 19,500 vehicle-kilometers (vkm)/yr, or an average of 29,250 pkm/yr. Multiplying this number by the number of hybrid cars in use (48.5 million) gives the total travel distance shifted (1.3 trillion pkm) from fossil fuel–powered ICE cars to hybrid cars (Table 4).

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Table 4. Current (2024) adoption level.

Unit: million pkm/yr

Population-weighted mean 1,318,000

Implied travel shifted from fossil fuel–powered cars to hybrid cars.

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Adoption Trend

Globally, the pkm driven in hybrid cars rather than fossil fuel–powered ICE cars increases by an average of about 178,200 million pkm/yr (Table 5). PHEV car purchases between 2019–2023 grew 45%/yr (IEA, 2024), while HEV purchases increased 10% annually between 2021–2023 (IEA, 2021, 2023). Global purchases of hybrid cars are increasing by around 6.1 million cars/yr. This is based on globally representative data (Bloomberg New Energy Finance [BloombergNEF], 2024; Fortune Business Insights, 2025; IEA, 2024; Menes, 2021).

It is worth noting that despite this impressive rate of growth, hybrid cars still have a long way to go before they replace a large percentage of the more than two billion cars currently driven (WHO, 2022).

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Table 5. 2023–2024 adoption trend.

Unit: million pkm/yr

Population-weighted mean 178,200

Implied travel shifted from fossil fuel–powered cars to hybrid cars.

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Adoption Ceiling

The total adoption ceiling for hybrid cars is equal to the total passenger-distance driven by private cars worldwide. Using a population-weighted mean of the average distance (in pkm) traveled per car annually, this translates to about 59 trillion pkm traveled (Table 6).

Replacing every single fossil fuel–powered ICE passenger car with a hybrid car would require an enormous upscaling of hybrid car production capacity, rapid development of charging infrastructure for PHEVs, cost reductions to make hybrid cars more affordable for more people, and technological improvements to make them more suitable for more kinds of drivers and trips. This shift would also face cultural obstacles from drivers who are attached to fossil fuel–powered cars (Roberts, 2022).

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Table 6. Adoption ceiling.

Unit: million pkm/yr

Population-weighted mean 59,140,000

Implied travel shifted from fossil fuel–powered cars to hybrid cars.

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Achievable Adoption

The achievable adoption of hybrid car travel is about 12-30 trillion pkm shifted from fossil fuel–powered ICE vehicles.

Various organizations have produced forecasts of future hybrid car adoption. These are not assessments of feasible adoption per se; they are instead predictions of likely rates of adoption, given various assumptions about the future (Bloomberg New Energy Finance, 2024; Fortune Business Insights, 2025; IEA, 2021, 2023, 2024). But they are useful in that they take a large number of variables into account. To convert these estimates of future likely adoption into estimates of the achievable adoption range, we applied some optimistic assumptions to the numbers in the scenario projections. 

To find a high rate of hybrid car adoption, we assumed that every country could reach the highest rate of adoption projected to occur for any country. Bloomberg (Bloomberg New Energy Finance, 2024) predicts that some countries will reach 20–50% hybrid vehicle stock share by 2030. We therefore set our high adoption rate at 50% adoption worldwide. This corresponds to 1.011 trillion total hybrid cars in use, or 29.6 trillion pkm traveled by hybrid cars (Table 7). An important caveat is that with a global supply constraint in the production of electric car batteries that are also used by hybrids, per-country adoption rates are somewhat zero-sum. Every hybrid car purchased in Japan is one that cannot be purchased somewhere else. This means that for the whole world to achieve 50% hybrid car stock share, global hybrid car production (especially battery production) would have to radically increase. 

To identify a lower feasible rate of electric car adoption, we took the lower end of Bloomberg’s 20–50% global hybrid car adoption ceiling. This is also the current adoption rate in the most intensive country (Japan at 20%), proving it feasible. This translates to 404 million hybrid cars, or 11.8 trillion pkm traveled by hybrid car.

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Table 7. Range of achievable adoption levels.

Unit: million pkm/yr

Current Adoption 1,318,000
Achievable – Low 11,830,000
Achievable – High 29,570,000
Adoption Ceiling 59,140,000
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Hybrid cars currently displace 0.036 Gt CO₂‑eq/yr of GHG emissions from the transportation system on a 100-yr basis (Table 8; 0.036 Gt CO₂‑eq/yr on a 20-yr basis).

If hybrid cars reach 20% of the global private car stock share as BloombergNEF (2024) projects, then with the current number of cars on the road, they will displace 0.321 Gt CO₂‑eq/yr GHG emissions on a 100-yr basis (0.319 Gt CO₂‑eq/yr on a 20-yr basis).

If hybrid cars globally reach 50% of global private car stock share, as BloombergNEF (2024) estimates might happen in some markets, they will displace 0.802 Gt CO₂‑eq/yr GHG emissions on a 100-yr basis (0.796 Gt CO₂‑eq/yr on a 20-yr basis).

If hybrid cars replace 100% of the global car fleet, they will displace 1.603 Gt CO₂‑eq/yr GHG emissions on a 100-yr basis (1.593 Gt CO₂‑eq/yr on a 20-yr basis).

These numbers are based on the present-day average fuel consumption for hybrids and include emissions intensity from electrical grids for PHEVs. If fuel efficiency continues to improve (including hybrids getting lighter) and grids become cleaner, the total climate impact from hybrids cars will increase.

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Table 8. Climate impact at different levels of adoption.

Unit: Gt CO₂‑eq/yr, 100-yr basis

Current Adoption 0.036
Achievable – Low 0.321
Achievable – High 0.802
Adoption Ceiling 1.603
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Additional Benefits

Air Quality

HEVs and PHEVs cars can reduce emissions of air pollutants, including sulfur oxides, sulfur dioxide, particulate matter, nitrogen oxides, and especially carbon monoxide and volatile organic compounds (Requia et al., 2018). Some air pollution reductions are limited (particularly particulate matter and ozone) because hybrid cars are heavy. The added weight can increase emissions from brakes, tires, and wear on the batteries (Carey, 2023; Jones, 2019).

Health

Because hybrid cars have lower tailpipe emissions than fossil fuel–powered ICE cars, they can reduce traffic-related air pollution, which is associated with asthma, lung cancer, increased emergency department visits for respiratory disease, and increased mortality (Anenberg et al., 2019). Transitioning to hybrid cars can reduce exposure to air pollution, improve health, and prevent premature mortality (Garcia et al., 2023; Larson et al., 2020; Peters et al., 2020).

The health benefits of lower traffic-related air pollution vary spatially and – for PHEVs – partly depend on how communities generate electricity (Choma et al., 2020). Racial and ethnic minority communities located near highways and major traffic corridors are disproportionately exposed to air pollution (Kerr et al., 2021). Transitioning to HEVs and PHEVs could improve health in marginalized urban neighborhoods located near highways, industry, or ports (Pennington et al., 2024). These benefits depend on an equitable distribution of hybrid cars and infrastructure to support the adoption of plug-in hybrid cars (Garcia et al., 2023). 

Income and Work

Adopting hybrid cars can lead to savings in a household’s energy burden spent on fuel, or the proportion of income spent on fuel for transportation (Vega-Perkins et al., 2023). Plug-in hybrids can be charged during off-peak times, leading to further reductions in transportation costs (Romm & Frank, 2006). Savings from HEVs and PHEVs may be especially important for low-income households because they have the highest energy burdens (Bell-Pasht, 2024). 

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Risks

There is some criticism against any solution that advocates for car ownership (electric cars in particular and hybrids – which use fossil fuels – by extension) and that the focus should be on solutions such as public transport systems that reduce car ownership and usage (Jones, 2019; Milovanoff et al., 2020).

There is potential for a rebound effect, where improved fuel efficiency encourages people to drive more, potentially offsetting some of the expected fuel and emissions savings. This can occur because lower fuel costs per kilometer make driving more affordable and so increase vehicle use.

There is a risk that allocating the limited global battery supply to hybrid cars might undermine the deployment of solutions that also require batteries but are more effective at avoiding GHG emissions (Castelvecchi, 2021). These could include electric buses, electric rail, and electric bicycles.

Mining minerals necessary to produce hybrid car batteries carries environmental and social risks. Such mining has been associated with significant harm, particularly in lower-income countries that supply many of these minerals (Agusdinata et al., 2018; Sovacool, 2019).

Hybrid cars might also pose additional safety risks due to their higher weight, which means that they have longer stopping distances and can cause greater damage in collisions and to pedestrians and cyclists (Jones, 2019). 

The operating efficiency depends on charging for PHEVs and braking intensity for all hybrids. The results of efficiency studies also depend on assumptions such as car type, fuel efficiency, battery size, electricity grid, km/yr, and car lifetime. 

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Interactions with Other Solutions

Reinforcing

The effectiveness of PHEVs in reducing GHG emissions increases as electricity grids become cleaner, since lower-carbon electricity further reduces the emissions associated with car charging. 

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Competing

Hybrid cars compete directly with electric cars for adoption as well as for batteries, public resources, and infrastructural investment.

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Scaling up the production of hybrid cars requires more mining of critical minerals, which could affect ecosystems that are valuable carbon sinks (Agusdinata et al., 2018).

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Traveling by bicycle, sidewalk, public transit network, fully electric car, or smaller electric vehicle (such as electric bicycle) provides a greater climate benefit than traveling by hybrid car. There is an opportunity cost to deploying hybrid cars because those resources could otherwise be used to support these more effective solutions (Asia-Pacific Economic Cooperation [APEC], 2024).

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Dashboard

Solution Basics

million passenger kilometers (million pkm)

t CO₂-eq (100-yr)/unit
019.5127.11
units/yr
Current 1.318×10⁶ 01.183×10⁷2.957×10⁷
Achievable (Low to High)

Climate Impact

Gt CO₂-eq (100-yr)/yr
Current 0.036 0.3210.802
US$ per t CO₂-eq
264
Gradual

CO₂ , CH₄, N₂O, BC

Trade-offs

Hybrid cars have higher embodied emissions than fossil fuel–powered ICE cars due to the presence of both an ICE and electric motor with a battery that has a GHG-intensive manufacturing process. While the embodied emissions are higher for hybrid cars than ICE cars, coupling them with operating emissions yields a carbon payback period of several years. Embodied emissions were outside the scope of this assessment.

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Action Word
Mobilize
Solution Title
Hybrid Cars
Classification
Highly Recommended
Lawmakers and Policymakers
  • Create time-bound government procurement policies and targets to transition government fleets to hybrid cars when fully electric cars aren’t possible.
  • Provide financial incentives such as tax breaks, subsidies, or grants for hybrid car production and purchases that gradually reduce as market adoption increases.
  • Provide complimentary benefits for hybrid car drivers, such as privileged parking areas, free tolls, and access schemes.
  • Use targeted financial incentives to help low-income communities buy hybrid cars and incentivize manufacturers to produce more affordable options.
  • Develop charging infrastructure, ensuring adequate spacing between stations and equitable distribution of stations.
  • Invest in R&D or implement regulations to improve manufacturing, adoption, supply chain standards, and circularity of hybrid cars – particularly batteries.
  • Transition fossil fuel electricity production to renewables while promoting the transition to hybrid cars.
  • Disincentivize fossil fuel–powered ICE car ownership by gradually introducing taxes, penalties, buy-back programs, or other mechanisms.
  • Offer one-stop shops for information on hybrid vehicles, including demonstrations and educational resources on cost savings, environmental impact, and maintenance.
  • Work with industry and labor leaders to construct new hybrid car plants and transition fossil fuel–powered ICE car manufacturing into hybrid car production.
  • Set regulations for sustainable use of hybrid car batteries and improve recycling infrastructure.
  • Join international efforts to promote and ensure supply chain environmental and human rights standards.
  • Incentivize or mandate life-cycle assessments and product labeling (e.g., Environmental Product Declarations).
  • Create, support, or join partnerships that offer information, training, and general support for hybrid car adoption.

Further information:

Practitioners
  • Produce and sell affordable hybrid car models.
  • Collaborate with dealers to provide incentives, low-interest financing, or income-based payment options.
  • Develop charging infrastructure, ensuring adequate spacing between stations and equitable distribution of stations.
  • Offer lifetime warranties for hybrid batteries and easy-to-understand maintenance instructions.
  • Invest in R&D to improve manufacturing, adoption, supply chain standards, and circularity of hybrid cars, particularly batteries.
  • Provide customers with real-world data to help alleviate fuel efficiency concerns.
  • Offer one-stop shops for information on hybrid cars, including educational resources on cost savings, environmental impact, optimal charging, and maintenance.
  • Work with policymakers and labor leaders to construct new hybrid car plants and transition fossil fuel–powered ICE car manufacturing into hybrid car production.
  • Join international efforts to promote and ensure supply chain environmental and human rights standards.
  • Invest in recycling and circular economy infrastructure.
  • Conduct life-cycle assessments and ensure product labeling (e.g., Environmental Product Declarations).
  • Create, support, or join partnerships that offer information, training, and general support for hybrid car adoption.

Further information:

Business Leaders
  • Set time-bound company procurement policies and targets to transition corporate fleets to hybrid cars when fully electric cars aren’t feasible and report on these metrics regularly.
  • Encourage supply chain partners to transition their delivery fleets to hybrid vehicles when fully electric cars aren’t feasible.
  • Take advantage of financial incentives, such as tax breaks, subsidies, or grants for hybrid car purchases.
  • Create purchasing agreements with hybrid car manufacturers to support stable demand and improve economies of scale.
  • Install charging stations and offer employee benefits for hybrid car drivers, such as privileged parking areas.
  • Invest in R&D to improve manufacturing, adoption, supply chain standards, and circularity of hybrid cars – particularly batteries.
  • Work with industry and labor leaders to transition fossil fuel–powered ICE car manufacturing into hybrid car production.
  • Advocate for financial incentives and policies that promote hybrid car adoption.
  • Join international efforts to promote and ensure supply chain environmental and human rights standards.
  • Educate employees, customers, and investors about the company's transition to hybrid cars and encourage them to learn more about them.
  • Offer one-stop shops for information on hybrid cars, including demonstrations and educational resources on cost savings, environmental impact, and maintenance.
  • Create, support, or join partnerships that offer information, training, and general support for hybrid car adoption.

Further information:

Nonprofit Leaders
  • Set time-bound organizational procurement policies and targets to transition fleets to hybrid cars when fully electric cars aren’t feasible.
  • Take advantage of financial incentives, such as tax breaks, subsidies, or grants for hybrid car purchases.
  • Advocate for financial incentives and policies that promote hybrid car adoption.
  • Install charging stations and offer employee benefits for hybrid car drivers, such as privileged parking areas.
  • Advocate for or provide improved charging infrastructure.
  • Offer workshops or support to low-income communities for purchasing and owning hybrid cars.
  • Work with industry and labor leaders to transition fossil fuel–powered ICE car manufacturing into hybrid car production.
  • Join international efforts to promote and ensure supply chain environmental and human rights standards.
  • Advocate for regulations on lithium-ion batteries and investments in recycling facilities.
  • Offer one-stop shops for information on hybrid cars, including demonstrations and educational resources on cost savings, environmental impact, and maintenance.
  • Create, support, or join partnerships that offer information, training, and general support for hybrid car adoption.

Further information:

Investors
  • Invest in hybrid car companies and companies that provide charging equipment or installation.
  • Pressure and support portfolio companies in transitioning their corporate fleets.
  • Pressure portfolio companies to establish and report on time-bound targets for corporate fleet transition and roll-out of employee incentives.
  • Invest in R&D to improve manufacturing, adoption, supply chain standards, and circularity of hybrid cars – particularly batteries.
  • Invest in hybrid car companies, associated supply chains, and end-user businesses like rideshare apps.
  • Join international efforts to promote and ensure supply chain environmental and human rights standards.
  • Create, support, or join partnerships that offer information, training, and general support for hybrid car adoption.
  • Offer low-interest loans for purchasing hybrid cars or charging infrastructure.

Further information:

Philanthropists and International Aid Agencies
  • Set time-bound organizational procurement policies to transition fleets to hybrid cars when fully electric cars aren’t feasible.
  • Install charging stations and offer employee benefits for hybrid car drivers, such as privileged parking areas.
  • Take advantage of financial incentives, such as tax breaks, subsidies, or grants for hybrid car purchases.
  • Advocate for financial incentives and policies that promote hybrid car adoption.
  • Advocate for or provide improved charging infrastructure.
  • Advocate for regulations on lithium-ion batteries and public investments in recycling facilities.
  • Offer financial services such as low-interest loans or grants for purchasing hybrid cars and charging equipment.
  • Offer workshops or support to low-income communities for purchasing and owning hybrid cars.
  • Work with industry and labor leaders to transition fossil fuel–powered ICE car manufacturing into hybrid car production.
  • Join international efforts to promote and ensure supply chain environmental and human rights standards.
  • Offer one-stop shops for information on hybrid vehicles, including demonstrations and educational resources on cost savings, environmental impact, and maintenance.
  • Create, support, or join partnerships that offer information, training, and general support for hybrid car adoption.

Further information:

Thought Leaders
  • If purchasing a new car, buy a hybrid car if fully electric isn’t feasible.
  • Take advantage of financial incentives, such as tax breaks, subsidies, or grants for hybrid car purchases.
  • Share your experiences with hybrid cars through social media and peer-to-peer networks, highlighting the cost savings, benefits, incentive programs, and troubleshooting tips.
  • Advocate for financial incentives and policies that promote hybrid car adoption.
  • Advocate for improved charging infrastructure.
  • Help improve circularity of hybrid car supply chains.
  • Conduct in-depth life-cycle assessments of hybrid cars in particular geographies.
  • Research ways to reduce weight and improve the performance of hybrid cars while appealing to customers.
  • Join international efforts to promote and ensure supply chain environmental and human rights standards.
  • Create, support, or join partnerships that offer information, training, and general support for hybrid car adoption.

Further information:

Technologists and Researchers
  • Improve circularity of hybrid car supply chains.
  • Reduce the amount of critical minerals required for hybrid car batteries.
  • Innovate low-cost methods to improve safety, labor standards, and supply chains in mining for critical minerals.
  • Increase the longevity of batteries.
  • Research ways to reduce weight and improve the performance of hybrid cars while appealing to customers.
  • Improve techniques to repurpose used hybrid car batteries for stationary energy storage.
  • Develop methods of adapting fossil fuel–powered car manufacturing and infrastructure to include electric components.

Further information:

Communities, Households, and Individuals
  • If purchasing a new car, buy a hybrid car when fully electric cars aren’t feasible.
  • Take advantage of financial incentives, such as tax breaks, subsidies, or grants for hybrid car purchases.
  • Share your experiences with hybrid cars through social media and peer-to-peer networks, highlighting the cost savings, benefits, incentive programs, and troubleshooting tips.
  • Help shift the narrative around hybrid cars by demonstrating capability and performance.
  • Advocate for financial incentives and policies that promote hybrid car adoption.
  • Advocate for improved charging infrastructure.
  • Help improve circularity of supply chains for hybrid car components.
  • Join international efforts to promote and ensure supply chain environmental and human rights standards.
  • Create, support, or join partnerships that offer information, training, and general support for hybrid car adoption.

Further information:

Sources
Evidence Base

Consensus of effectiveness in reducing emissions: Mixed

There is a high level of consensus that hybrid cars emit fewer GHGs per kilometer traveled compared to fossil fuel–powered ICE cars. Hybrid cars achieve these reductions by combining an ICE with an electric motor that improves fuel efficiency and, for some models, allow for limited all-electric driving, further reducing fuel consumption and emissions. This advantage is strongest in places where trips are short and require a lot of braking, such as in cities. 

Globally, cars and vans were responsible for 3.8 Gt CO₂‑eq emissions in 2023 – more than 60% of road transport emissions (IEA, 2024).

Major climate research organizations generally see hybrid cars as a transitional means of reducing GHG emissions from passenger transportation. These technologies offer immediate emissions reductions while the electricity grid decarbonizes and battery technology improves. Any improvement to fuel efficiency or time spent driving electrically reduces emissions. These technologies can be a gateway to fully electric cars by eliminating range anxiety and allowing drivers the experience of electric driving without fully committing to the limitations of current EV infrastructure. 

Hybrid cars, while more fuel-efficient than fossil fuel–powered ICE cars, still rely on gasoline or diesel, meaning they continue to produce tailpipe emissions and contribute to air pollution. Additionally, their dual powertrains add complexity, leading to higher embodied emissions, manufacturing costs, increased maintenance requirements, and potential long-term reliability concerns. The added weight from both an ICE and an electric motor, along with a battery pack, can reduce overall efficiency and raise safety concerns. Embodied emissions are outside the scope of this assessment.

The International Council on Clean Transportation (ICCT; Isenstadt & Slowik (2025) estimated that HEVs reduce tailpipe GHG emissions by 30% while costing an average of US$2,000 more upfront. Over a 10-yr period, they offered an estimated fuel cost savings of US$4,500. ICCT expected future HEVs to achieve an additional 15% reduction in GHG emissions, with a decrease in the price premium of US$300–800. PHEVs reduce GHG emissions by 11–30%, depending on emissions intensity of the electric grid and the proportion of distance driven electrically. 

The IEA (2024) noted that a PHEV bought in 2023 will emit 30% less GHGs than a fossil fuel–powered ICE car over its lifetime. This includes full life cycle impacts, including those from producing the car. 

The International Transport Forum (2020) estimated that fossil fuel–powered ICE cars emit 162 g CO₂‑eq/pkm while HEVs emit 132 g CO₂‑eq/pkm and PHEVs emit 124 g CO₂‑eq/pkm. This includes embodied and upstream emissions.

The results presented in this document summarize findings from 12 reviews and meta-analyses and 29 original studies reflecting current evidence from 72 countries, primarily from the IEA’s Global Electric Vehicle Outlook (2024) and Electric Vehicles: Total Cost of Ownership Tool (2022) and the International Transport Forum’s life-cycle analysis on sustainable transportation (2020). We recognize this limited geographic scope creates bias, and hope this work inspires research and data sharing on this topic in underrepresented regions.

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Increase Centralized Composting

Submitted by Drawdown Admin on
Sector
Industry, Materials & Waste
Mode
Cut Emissions
Cluster
Use Waste as a Resource
Image
Centralized composting facility
Coming Soon
On
Summary

A composting system diverts organic waste (OW) from landfills, reducing the production of methane and other GHG emissions.OW is defined as the combination of food waste and green waste, composed of yard and garden trimmings. Composting transforms it into a nutrient-rich soil supplement.

Our focus is on centralized (city- or regional-level) composting systems for the OW components of municipal solid waste (MSW). Decentralized (home- and community-level) and on-farm composting are also valuable climate actions, but are not included here due to limited data availability at the global level (see Increase Decentralized Composting).

Income & work,Health,Equality
Land resources,Water resources,Air quality
Description for Social and Search
Increase Centralized Composting reduces methane and other GHG emissions by diverting organic waste from landfills to composting facilities that repurpose waste into nutrient-rich soil supplements.
Overview

There are many stages involved in a composting system to convert organic MSW into finished compost that can be used to improve soil health (Figure 1). Within this system, composting is the biochemical process that transforms OW into a soil amendment rich in nutrients and organic matter. 

Figure 1. Stages of a composting system. Solution boundaries exclude activities upstream and downstream of centralized MSW composting such as waste collection and compost application. Modified from Kawai et al. (2020) and Manea et al. (2024).

Diagram demonstrating process steps for landfill and compost materials.

Source: Kawai et al. (2020) and Manea et al. (2024).

The composting process is based on aerobic decomposition, driven by complex interactions among microorganisms, biodegradable materials, and invertebrates and mediated by water and oxygen (see the Appendix). Without the proper balance of oxygen and water, anaerobic decomposition occurs, leading to higher methane emissions during the composting process (Amuah et al., 2022; Manea et al., 2024). Multiple composting methods can be used depending on the amounts and composition of OW feedstocks, land availability, labor availability, finances, policy landscapes, and geography. Some common methods include windrow composting, bay or bin systems, and aerated static piles (Figure 2; Amuah et al., 2022; Ayilara et al., 2020; Cao et al., 2023).

Figure 2. Examples of commonly used centralized composting methods. Bay systems (left) move organics between different bays at different stages of the composting process. Windrows (center) are long, narrow piles that are often turned using large machinery. Aerated static piles (right) can be passively aerated as shown here or actively aerated with specialized blowing equipment.

Decentralized composting examples

Credit: Bays, iStock | nikolay100; Windrows, iStock | Jeremy Christensen; Aerated static pile, iStock | AscentXmedia

Centralized composting generally refers to processing large quantities (> 90 t/week) of organic MSW (Platt, 2017). Local governments often manage centralized composting as part of an integrated waste management system that can also include recycling non-OW, processing OW anaerobically in methane digesters, landfilling, and incineration (Kaza et al., 2018). 

Organic components of MSW include food waste and garden and yard trimmings (Figure 2). In most countries and territories, these make up 40–70% of MSW, with food waste as the largest contribution (Ayilara et al., 2020; Cao et al., 2023; Food and Agriculture Organization [FAO], 2019; Kaza et al., 2018; Manea et al., 2024; U.S. Environmental Protection Agency [U.S. EPA], 2020; U.S. EPA, 2023). 

Diverting OW, particularly food waste, from landfill disposal to composting reduces GHG emissions (Ayilara et al., 2020; Cao et al., 2023; FAO, 2019). Diversion of organics from incineration could also have emissions and pollution reduction benefits, but we did not include incineration as a baseline disposal method for comparison since it is predominantly used in high-capacity and higher resourced countries and contributes less than 1% to annual waste-sector emissions (Intergovernmental Panel On Climate Change [IPCC], 2023; Kaza et al., 2018). 

Disposal of waste in landfills leads to methane emissions estimated at nearly 1.9 Gt CO₂‑eq (100-yr basis) annually (International Energy Agency [IEA], 2024). Landfill emissions come from anaerobic decomposition of inorganic waste and OW and are primarily methane with smaller contributions from ammonia, nitrous oxide, and CO₂ (Cao et al., 2023; Kawai et al., 2020; Manea et al., 2024). Although CO₂, methane, and nitrous oxide are released during composting, methane emissions are up to two orders of magnitude lower than emissions from landfilling (Ayilara et al., 2020; Cao et al, 2023; FAO, 2019; IEA, 2024; Nordahl et al., 2023; Perez et al., 2023). GHG emissions can be minimized by fine-tuning the nutrient balance during composting. 

Depending on the specifics of the composting method used, the full transformation from initial feedstocks to finished compost can take weeks or months (Amuah et al., 2022; Manea et al., 2024; Perez et al., 2023). Finished compost can be sold and used in a variety of ways, including application to agricultural lands and green spaces as well as for soil remediation (Gilbert et al., 2020; Platt et al., 2022; Ricci-Jürgensen et al., 2020a; Sánchez et al., 2025). 

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United Nations Environment Programme. (2024). Global Waste Management Outlook 2024 Beyond an age of waste: Turning rubbish into a resource. United Nations Environment Programme. Link to source: https://www.unep.org/resources/global-waste-management-outlook-2024 

Urra, J., Alkorta, I., & Garbisu, C. (2019). Potential benefits and risks for soil health derived from the use of organic amendments in agriculture. Agronomy, 9(9), 542. Link to source: https://doi.org/10.3390/agronomy9090542

Wilson, D. C., Paul, J., Ramola, A., & Filho, C. S. (2024). Unlocking the significant worldwide potential of better waste and resource management for climate mitigation: With particular focus on the Global South. Waste Management & Research: The Journal for a Sustainable Circular Economy, 42(10), 860–872. Link to source: https://doi.org/10.1177/0734242X241262717

World Bank. (2018). What a waste global database: Country-level dataset. (Last Updated: June 4, 2024) [Data set]. World Bank. Link to source: https://datacatalogfiles.worldbank.org/ddh-published/0039597/3/DR0049199/country_level_data.csv 

Yasmin, N., Jamuda, M., Panda, A. K., Samal, K., & Nayak, J. K. (2022). Emission of greenhouse gases (GHGs) during composting and vermicomposting: Measurement, mitigation, and perspectives. Energy Nexus, 7, Article 100092. Link to source: https://doi.org/10.1016/j.nexus.2022.100092

Zaman, A. U. (2016). A comprehensive study of the environmental and economic benefits of resource recovery from global waste management systems. Journal of Cleaner Production, 124, 41–50. Link to source: https://doi.org/10.1016/j.jclepro.2016.02.086

Zero Waste Europe & Bio-based Industries Consortium. (2024). Bio-waste generation in the EU: Current capture levels and future potential (Second edition). LIFE Programme of the European Union. Link to source: https://zerowasteeurope.eu/library/bio-waste-generation-in-the-eu-current-capture-levels-and-future-potential-second-edition/ 

Zhu, J., Luo, Z., Sun, T., Li, W., Zhou, W., Wang, X., Fei, X., Tong, H., & Yin, K. (2023). Cradle-to-grave emissions from food loss and waste represent half of total greenhouse gas emissions from food systems. Nature Food, 4(3), 247–256. Link to source: https://doi.org/10.1038/s43016-023-00710-3

Credits

Lead Fellow

  • Megan Matthews, Ph. D.

Contributors

  • Ruthie Burrows, Ph.D.

  • James Gerber, Ph.D.

  • Daniel Jasper

  • Alex Sweeney

Internal Reviewers

  • Aiyana Bodi

  • Hannah Henkin

  • Ted Otte

  • Sarah Gleeson, Ph. D.

  • Amanda D. Smith, Ph.D.

  • Paul C. West, Ph.D.

Effectiveness

We estimated that composting reduces emissions by 3.9 t CO₂‑eq /t OW (9.3 t CO₂‑eq /t OW, 20-yr basis) based on avoided landfill emissions minus the emissions during composting of MSW OW (Table 1). In our analysis, composting emissions were an order of magnitude lower than landfill emissions.

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Table 1. Effectiveness at reducing emissions. 

Unit: t CO₂‑eq (100-yr basis)/t OW

25th percentile 2.5
mean 3.2
median (50th percentile) 3.9
75th percentile 4.3
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Emissions data from composting and landfilling OW are geographically limited, but our analysis includes three global reports and studies from the U.S., China, Denmark, and the EU (European Energy Agency [EEA], 2024; Industrious Labs, 2024; Perez et al., 2023; U.S. EPA, 2020; Yang et al., 2017, Yasmin et al., 2022). We assumed OW was 39% of MSW in accordance with global averages (Kaza et al., 2018; World Bank, 2018).

We estimated that landfills emit 4.3 t CO₂‑eq /t OW (9.9 t CO₂‑eq /t OW, 20-yr basis). We estimated composting emissions were 10x lower at 0.4 t CO₂‑eq /t OW (0.6 t CO₂‑eq /t OW, 20-yr basis). We quantified emissions from a variety of composting methods and feedstock mixes (Cao et al., 2023; Perez et al., 2023; Yasmin et al., 2022). Consistent with Amuah et al. (2022), we assumed a 60% moisture content by weight to convert reported wet waste quantities to dry waste weights.

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Cost

Financial data were geographically limited. We based cost estimates on global reports with selected studies from the U.K., U.S., India, and Saudi Arabia for landfilling and the U.S. and Sri Lanka for composting. Transportation and collection costs can be significant in waste management, but we did not include them in this analysis. We calculated amortized net cost for landfilling and composting by subtracting revenues from operating costs and amortized initial costs over a 30-yr facility lifetime.

Landfill initial costs are one-time investments, while operating expenses, which include maintenance, wages, and labor, vary annually. Environmental costs, including post-closure operations, are not included in our analysis, but some countries impose taxes on landfilling to incentivize alternative disposal methods and offset remediation costs. Landfills generate revenue through tip fees and sales of landfill gas (Environmental Research & Education Foundation [EREF], 2023; Kaza et al., 2018). We estimated that landfilling is profitable, with a net cost of –US$30/t OW. 

Initial and operational costs for centralized composting vary depending on method and scale (IPCC, 2023; Manea et al., 2024), but up-front costs are generally cheaper than landfilling. Since composting is labor-intensive and requires monitoring, operating costs can be higher, particularly in regions that do not impose landfilling fees (Manea et al., 2024). 

Composting facilities generate revenue through tip fees and sales of compost products. Compost sales alone may not be sufficient to recoup costs, but medium- to large-scale composting facilities are economically viable options for municipalities (Kawai et al., 2020; Manea et al., 2024). We estimated the net composting cost to be US$20/t OW. The positive value indicates that composting is not globally profitable; however, decentralized systems that locally process smaller waste quantities can be profitable using low-cost but highly efficient equipment and methods (see Increase Decentralized Composting). 

We estimated that composting costs US$50/t OW more than landfilling. Although composting systems cost more to implement, the societal and environmental costs are greatly reduced compared to landfilling (Yasmin et al., 2022). The high implementation cost is a barrier to adoption in lower-resourced and developing countries (Wilson et al., 2024). 

Combining effectiveness with the net costs presented here, we estimated a cost per unit climate impact of US$10/t CO₂‑eq (US$5/t CO₂‑eq , 20-yr basis) (Table 2). 

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Table 2. Cost per unit climate impact.

Unit: US$ (2023)/t CO₂‑eq (100-yr basis)

median 10
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Learning Curve

Global cost data on composting are limited, and costs can vary depending on composting methods, so we did not quantify a learning rate for centralized composting.

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Speed of Action

Speed of action refers to how quickly a climate solution physically affects the atmosphere after it is deployed. This is different from speed of deployment, which is the pace at which solutions are adopted.

At Project Drawdown, we define the speed of action for each climate solution as emergency brake, gradual, or delayed.

Increase Centralized Composting is an EMERGENCY BRAKE climate solution. It has the potential to deliver a more rapid impact than nominal and delayed solutions. Because emergency brake solutions can deliver their climate benefits quickly, they can help accelerate our efforts to address dangerous levels of climate change. For this reason, they are a high priority.

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Caveats

The composting process has a low risk of reversal since carbon is stored stably in finished compost instead of decaying and releasing methane in a landfill (Ayilara et al., 2020; Manea et al., 2024). However, a composting system, from collection to finished product, can be challenging to sustain. Along with nitrogen-rich food and green waste, carbon-rich bulking materials are critical for maintaining optimal composting conditions that minimize GHG emissions. Guaranteeing the availability of sufficient bulking materials can challenge the success of both centralized and decentralized facilities.

Financially and environmentally sustainable composting depends not only on the quality of incoming OW feedstocks, but also on the quality of the final product. Composting businesses require a market for sales of compost products (in green spaces and/or agriculture), and poor source separation could lead to low-quality compost and reduced demand (Kawai et al., 2020; Wilson et al., 2024). Improvements in data collection and quality through good feedback mechanisms can also act as leverage for expanding compost markets, pilot programs, and growing community support.

If composting facilities close due to financial or other barriers, local governments may revert to disposing of organics in landfills. Zoning restrictions also vary broadly across geographies, affecting how easily composting can be implemented (Cao et al., 2023). In regions where centralized composting is just starting, reversal could be more likely without community engagement and local government support (Kawai et al., 2020; Maalouf & Agamuthu, 2023); however, even if facilities close, the emissions savings from past operation cannot be reversed.

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Current Adoption

Table 3. Current adoption level (2021).

Unit: t OW composted/yr

25th percentile 67,000,000
mean 78,000,000
median (50th percentile) 78,000,000
75th percentile 89,000,000
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We estimated global composting adoption at 78 million t OW/yr, as the median between two datasets. The most recent global data on composting were compiled in 2018 from an analysis from 174 countries and territories (World Bank, 2018). We also used an Organization for Economic Co-operation and Development (OECD) analysis from 45 countries (OECD, 2021). However, there were still many countries and territories that did not report composting data in one or both datasets. Although the World Bank dataset is comprehensive, it is based on data collected in 2011–2018, so more recent, high-quality, global data on composting are needed.

Globally, nearly 40% of all waste is disposed of in landfills, 19% is recovered through composting and other recovery and recycling methods, and the remaining waste is either unaccounted for or disposed of through open dumping and wastewater (Kaza et al., 2018).

We calculated total tonnage composted using the reported composting percentages and the total MSW tonnage for each country. Composting percentages were consistently lower than the total percentage of OW present in MSW, suggesting there is ample opportunity for increased composting, even in geographies where it is an established disposal method. In 2018, 26 countries/territories had a composting rate above 10% of MSW, and 15 countries/territories had a composting rate above 20% of MSW. Countries with the highest composting rates were Austria (31%), the Netherlands (27%), and Switzerland (21%) (World Bank, 2018).

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Adoption Trend

Table 4: Adoption trend (2014–2021)

Unit: t OW composted/yr/yr

25th percentile -1,200,000
mean -1,300,000
median (50th percentile) 260,000
75th percentile 4,300,000
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We used OECD data to estimate the composting adoption trend from 2014–2021 (OECD, 2021), which fluctuated significantly from year to year (Table 4). Negative rates indicate less OW was composted globally than in the previous year. Taking the median composting rate across seven years, we estimate the global composting trend as 260,000 t OW/yr/yr. However, the mean composting trend is –1.3 Mt OW/yr/yr, suggesting that on average, composting rates are decreasing globally. 

Although some regions are increasing their composting capacity, others are either not composting or composting less over time. Germany, Italy, Spain, and the EU overall consistently show increases in composting rates year-to-year, while Greece, Japan, Türkiye, and the U.K. show decreasing composting rates. In Europe, the main drivers for consistent adoption were disposal costs, financial penalties, and the landfill directive (Ayilara et al., 2020). 

Lack of reported data could also contribute to a negative global average composting rate over the past seven years. A large decline in composting rates from 2018–2019 was driven by a lack of data in 2019 for the U.S. and Canada. If we assumed that the U.S. composted the same tonnage in 2019 as in 2018, instead of no tonnage as reported in the data, then the annual trend for 2018–2019 is much less negative (–450,000 t OW/yr/yr) and the overall mean trend between 2014–2019 would be positive (1,400,000 t OW/yr/yr).

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Adoption Ceiling

Table 5: Adoption ceiling. upper limit for adoption level.

Unit: t OW composted/yr

median (50th percentile) 991,000,000
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We estimate the global adoption ceiling for Increase Centralized Composting to be 991 million t OW/yr (Table 5). In 2016, 2.01 Gt of MSW were generated, and generation is expected to increase to 3.4 Gt by 2050 (Kaza et al., 2018). Due to limited global data availability on composting infrastructure or policies, we estimated the adoption ceiling based on the projected total MSW for 2050 and assumed the OW fraction remains the same over time.

In reality, amounts of food waste within MSW are also increasing, suggesting that there are sufficient global feedstocks to support widespread composting adoption (Zhu et al., 2023). 

We assume that 75% of OW could be processed via composting and the remaining 25% via methane digesters (see Deploy Methane Digesters). Biowaste from MSW makes up approximately 15% of incoming feedstocks for methane digesters (IEA, 2025). 

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Achievable Adoption

Table 6. Range of achievable adoption levels.

Unit: t OW composted/yr

Current Adoption 78,000,000
Achievable – Low 156,000,000
Achievable – High 244,000,000
Adoption Ceiling 91,000,000
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Since the global annual trend fluctuates, we used country-specific composting rates and organic fractions of MSW from 2018 to estimate the achievable range of composting adoption (see Appendix for an example). In our analysis, achievable increases in country-specific composting rates cannot exceed the total organic fraction of 2018 MSW. 

For the 106 countries/territories that did not report composting rates, we defined achievable levels of composting relative to the fraction of OW in MSW. When countries also did not report OW percentages, the country-specific composting rate was kept at zero. For the remaining 86 countries/territories, we assumed that 25% of organic MSW could be diverted to composting for low achievable adoption and that 50% could be diverted for high achievable adoption. 

For the 68 countries/territories with reported composting rates, we define low and high achievable adoption as a 25% or 50% increase to the country-specific composting rate, respectively. If the increased rate for either low or high adoption exceeded the country-specific OW fraction of MSW, we assumed that all organic MSW could be composted (see Appendix for an example). Our Achievable – Low adoption level is 156 Mt OW/yr, or 16% of our estimated adoption ceiling. Our Achievable – High adoption level is 244 Mt OW/yr, or 25% of our estimated adoption ceiling. 

Our estimated adoption levels are conservative because some regions without centralized composting of MSW could have subnational decentralized composting programs that aren’t reflected in global data.

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Table 7. Climate impact at different levels of adoption.

Unit: Gt CO₂‑eq (100-yr basis)/yr

Current Adoption 0.30
Achievable – Low 0.60
Achievable – High 0.95
Adoption Ceiling 3.8
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Although our achievable range is conservative compared to the estimated adoption ceiling, increased composting has the potential to reduce GHG emissions from landfills (Table 7). We estimated that current adoption reduces annual GHG emissions by 0.3 Gt CO₂‑eq/yr (0.73 Gt CO₂‑eq/yr, 20-yr basis). Our estimated low and high achievable adoption levels reduce 0.60 and 0.95 Gt CO₂‑eq/yr (1.4 and 2.3 Gt CO₂‑eq/yr, 20-yr basis), respectively. Using the adoption ceiling, we estimate that annual GHG reductions increase to 3.8 Gt CO₂‑eq/yr (9.2 Gt CO₂‑eq/yr, 20-yr basis).

The IPCC estimated in 2023 that the entire waste sector accounted for 3.9% of total global GHG emissions, and solid waste management represented 36% of total waste sector emissions (IPCC, 2023). Disposal of waste in landfills leads to methane emissions estimated at nearly 1.9 Gt CO₂‑eq (100-yr basis) annually (IEA, 2024). Based on these estimates, current composting adoption reduces annual methane emissions from landfills more than 16%. 

Increasing adoption to low and high achievable levels could reduce the amount of OW going to landfills by up to 40% and avoid 32–50% of landfill emissions. Reaching our estimated adoption ceilings for both Increase Centralized Composting and Deploy Methane Digesters solutions could avoid all food-related landfill emissions.

These climate impacts can be considered underestimates of beneficial mitigation from increased composting since we did not quantify the carbon sequestration benefits of compost application and reduced synthetic fertilizer use. Our estimated climate impacts from composting are also an underestimate because we didn’t include decentralized composting. 

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Additional Benefits

Income and Work

Composting creates more jobs than landfills or incinerators and can save money compared with other waste management options (Bekchanov & Mirzabaev, 2018; Farhidi et al., 2022; Platt et al., 2013; Zaman, 2016). It is less expensive to build and maintain composting plants than incinerators (Kawai et al., 2020). According to a survey of Maryland waste sites, composting creates twice as many jobs as landfills and four times as many jobs as incineration plants (Platt et al., 2013). Composting also indirectly sustains jobs in the distribution and use of compost products (Platt et al., 2013). Compost is rich in nutrients and can also reduce costs associated with synthetic fertilizer use in agriculture (Farhidi et al., 2022).

Health

Composting can reduce exposures to landfill and waste-to-energy facility emissions, which have been linked to health issues such as lung cancer, respiratory and neurological problems, low birth weight, and birth defects (Brender et al., 2011; Industrious Labs, 2024; Nguyen et al., 2023; Siddiqua et al., 2022). Odors coming from anaerobic decomposition landfills, such as ammonia and hydrogen sulfide, are another source of pollutants that impact human well-being, which can be reduced by aerobic composting (Cai et al., 2018).

Equality

Reducing community exposure to air pollution from landfills through composting has implications for environmental justice (Casey et al., 2021; Nguyen et al., 2023). A large review of waste sites in the United States and Europe found that landfills are disproportionately located near populations with low socioeconomic status and near racially and ethnically marginalized neighborhoods (Marzutti et al., 2010). Reducing disproportionate exposures to air pollution from landfills may mitigate poor health outcomes in surrounding communities (Brender et al., 2011)

Land Resources

Compost provides an important soil amendment that adds organic matter and nutrients to soil, reducing the need for synthetic fertilizers (Urra et al., 2019; U.S. EPA, 2025). Healthy soils that are rich in organic matter can benefit the surrounding ecosystem and watershed and lead to more plant growth through improved water retention and filtration, improved soil quality and structure, and reduced erosion and nutrient runoff (Bell & Platt, 2014; Martinez-Blanco et al., 2013; U.S. EPA, 2025). By reducing the need for synthetic fertilizers and by improving soils’ ability to filter and conserve water, compost can also reduce eutrophication of water bodies (U.S. EPA, 2025). These soil benefits are partially dependent on how compost is sorted because there may be risks associated with contamination of microplastics and heavy metals (Manea et al., 2024; Urra et al., 2019).

Water Resources

For a description of the water resources benefits, please refer to the “land resources” subsection. 

Air Quality

Composting can reduce air pollution such as CO₂, methane, volatile organic compounds, and particulate matter that is commonly released from landfills and waste-to-energy systems (Kawai et al., 2020; Nordahl et al., 2020; Siddiqua et al., 2022). An analysis comparing emissions from MSW systems found composting to have lower emissions than landfilling and other waste-to-energy streams (Nordahl et al., 2020). Composting can also reduce the incidence of landfill fires, which release black carbon and carbon monoxide, posing risks to the health and safety of people in nearby communities (Nguyen et al., 2023).

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Risks

Before the composting process can start, feedstocks are sorted to remove potential contaminants, including nonbiodegradable materials such as metal and glass as well as plastics, bioplastics, and paper products (Kawai et al., 2020; Perez et al., 2023; Wilson et al., 2024). While most contaminants can be removed through a variety of manual and mechanical sorting techniques, heavy metals and microplastics can become potential safety hazards or reduce finished compost quality (Manea et al., 2024). Paper and cardboard should be separated from food and green waste streams because they often contain contaminants such as glue or ink, and they degrade more slowly than other OW, leading to longer processing time and lower-quality finished compost (Kawai et al., 2020; Krause et al., 2023).

Successful and safe composting requires careful monitoring of compost piles to avoid anaerobic conditions and ensure sufficient temperatures to kill pathogens and weed seeds (Amuah et al., 2022; Ayilara et al., 2020; Cao et al., 2023; Kawai et al., 2020; Manea et al., 2024). Anaerobic conditions within the compost pile increase GHGs emitted during composting. Poorly managed composting facilities can also pose safety risks for workers and release odors, leading to community backlash (Cao et al., 2023; Manea et al., 2024; UNEP, 2024). Regional standards, certifications, and composter training programs are necessary to protect workers from hazardous conditions and to guarantee a safe and effective compost product (Kawai et al., 2020). Community outreach and education on the benefits of separating waste and composting prevent “not-in-my-backyard” attitudes or “NIMBYism” that may lead to siting composting facilities further from the communities they serve.

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Interactions with Other Solutions

Reinforcing

Increased composting could positively impact annual cropping by providing consistent, high-quality finished compost that can reduce dependence on synthetic fertilizers and improve soil health and crop yields. 

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High-quality sorting systems also allow for synergies that benefit all waste streams and create flexible, resilient waste management systems. Improving waste separation programs for composting can have spillover effects that also improve other waste streams, such as recyclables, agricultural waste, or e-waste. Access to well-sorted materials can also help with nutrient balance for various waste streams, including agricultural waste.

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Composting facilities require a reliable source of carbon-rich bulking material. Agricultural waste can be diverted to composting rather than burning to reduce emissions from crop residue burning. 

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Competing

Diverting OW from landfills will lead to lower landfill methane emissions and, therefore, less methane available to be captured and resold as revenue.

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OW diverted from landfills can also be managed using anaerobic digestion in methane digesters, which reduces the available volumes of OW for composting.

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Dashboard

Solution Basics

t organic waste

t CO₂-eq (100-yr)/unit
02.53.9
units/yr
Current 7.8×10⁷ 01.56×10⁸2.44×10⁸
Achievable (Low to High)

Climate Impact

Gt CO₂-eq (100-yr)/yr
Current 0.3 0.60.95
US$ per t CO₂-eq
10
Emergency Brake

CO₂,  CH₄

Trade-offs

Robust collection networks and source separation of OW are vital for successful composting, but they also increase investment costs. However, well-sorted OW can reduce the need for separation equipment and allow for simpler facility designs, leading to lower operational costs. The emissions from transporting OW are not included here, but are expected to be significantly less than the avoided landfill emissions. Composting facilities are typically located close to the source of OW (Kawai et al., 2020; U.S. Composting Council [USCC], 2008), but since centralized composting facilities are designed to serve large communities and municipalities, there can be trade-offs between sufficient land availability and distance from waste sources.

We also exclude emissions from onsite vehicles and equipment such as bulldozers and compactors, assuming that those emissions are small compared to the landfill itself.

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Action Word
Increase
Solution Title
Centralized Composting
Classification
Highly Recommended
Lawmakers and Policymakers
  • Establish zero waste and OW diversion goals; incorporate them into local or national climate plans and soil health and conservation policies.
  • Ensure public procurement uses local compost when possible.
  • Participate in consultations with farmers, businesses, and the public to determine where to place plants, how to use compost, pricing, and how to roll out programs.
  • Establish or improve existing centralized composting facilities, collection networks, and storage facilities.
  • Establish incentives and programs to encourage both centralized and decentralized composting.
  • Work with farmers, local gardeners, the private sector, and local park systems to develop markets for compost.
  • Invest in source separation education and waste separation technology that enhances the quality of final compost products.
  • Regulate the use of waste separation technologies to prioritize source separation of waste and the quality of compost products.
  • Ensure low- and middle-income households are served by composting programs with particular attention to underserved communities such as multi-family buildings and rural households.
  • Enact extended producer responsibility approaches that hold producers accountable for waste.
  • Create demonstration projects to show the effectiveness and safety of finished compost.
  • Ensure composting plants are placed as close to farmland as possible and do not adversely affect surrounding communities.
  • Streamline permitting processes for centralized compost facilities and infrastructure.
  • Establish laws or regulations that require waste separation as close to the source as possible, ensuring the rules are effective and practical.
  • Establish zoning policies that support both centralized and decentralized composting efforts, including at the industrial, agricultural, community, and backyard scales.
  • Establish fees or fines for OW going to landfills; use funds for composting programs.
  • Use financial instruments such as taxes, subsidies, or exemptions to support infrastructure, participation, and waste separation.
  • Partner with schools, community gardens, farms, nonprofits, women’s groups, and other community organizations to promote composting and teach the importance of waste separation.
  • Establish one-stop-shop educational programs that use online and in-person methods to teach how to separate waste effectively and why it’s important.
  • If composting is not possible or additional infrastructure is needed, consider methane digesters as alternatives to composting.
  • Create, support, or join certification programs that verify the quality of compost and/or verify food waste suppliers such as hotels, restaurants, and cafes.

Further information:

Practitioners
  • Work with policymakers and local communities to establish zero-waste and OW diversion goals for local or national climate plans.
  • Participate in consultations with farmers, policymakers, businesses, and the public to determine where to place plants, how to use compost, pricing, and how to roll out programs.
  • Work with farmers, local gardeners, the private sector, and local park systems to create quality supply streams and develop markets for compost.
  • Invest in source separation education and waste separation technology that enhances the quality of final compost products.
  • Establish one-stop-shop educational programs that use online and in-person methods to teach how to separate waste effectively and why that’s important.
  • Ensure low- and middle-income households are served by composting programs with particular attention to underserved communities such as multi-family buildings and rural households.
  • Create demonstration projects to show the effectiveness and safety of finished compost.
  • Ensure composting plants are placed as close to farmland as possible and do not adversely affect surrounding communities.
  • Take advantage of financial incentives such as subsidies or exemptions to set up centralized composting infrastructure, increase participation, and improve waste separation.
  • Partner with schools, community gardens, farms, nonprofits, women’s groups, and other community organizations to promote composting and teach the importance of waste separation.
  • Consider partnerships through initiatives such as sister cities to share innovation and develop capacity.
  • If additional infrastructure is needed, consider methane digesters as alternatives to composting.
  • Create, support, or join certification programs that verify the quality of compost and/or verify food waste suppliers such as hotels, restaurants, and cafes.

Further information:

Business Leaders
  • Establish zero-waste and OW diversion goals; incorporate the goals into corporate net-zero strategies.
  • Ensure procurement uses strategies to reduce FLW at all stages of the supply chain; consider using the Food Loss and Waste Protocol.
  • Ensure corporate procurement and facilities managers use local compost when possible.
  • Participate in consultations with farmers, policymakers, and the public to determine where to place plants, how to use compost, pricing, and how to roll out programs.
  • Work with farmers, local gardeners, the private sector, and local park systems to develop markets for compost.
  • Offer employee pre-tax benefits on materials to compost at home or participate in municipal composting programs.
  • Offer financial services, including low-interest loans, microfinancing, and grants, to support composting initiatives.
  • Support extended producer responsibility approaches that hold producers accountable for waste.
  • Educate employees on the benefits of composting, include them in companywide waste diversion initiatives, and encourage them to use and advocate for municipal composting in their communities. Clearly label containers and signage for composting.
  • Partner with schools, community gardens, farms, nonprofits, women’s groups, and other community organizations to promote composting and teach the importance of waste separation.
  • Create, support, or join certification programs that verify the quality of compost and/or verify food waste suppliers such as hotels, restaurants, and cafes.

Further information:

Nonprofit Leaders
  • Help policymakers establish zero-waste and OW diversion goals; help incorporate them into local or national climate plans.
  • Ensure organizational procurement uses local compost when possible.
  • Help administer, fund, or promote local composting programs.
  • Help gather data on local OW streams, potential markets, and comparisons of alternative uses such as methane digesters.
  • Participate in consultations with farmers, policymakers, businesses, and the public to determine where to place plants, how to use compost, pricing, and how to roll out programs.
  • Work with farmers, local gardeners, the private sector, and local park systems to develop markets for compost.
  • Help ensure low- and middle-income households are served by composting programs with particular attention to underserved communities such as multi-family buildings and rural households.
  • Advocate for extended producer responsibility approaches that hold producers accountable for waste.
  • Advocate for laws or regulations that require waste separation as close to the source as possible, ensuring the rules are effective and practical.
  • Create demonstration projects to show the effectiveness and safety of finished compost.
  • Establish one-stop-shop educational programs that use online and in-person methods to teach how to separate waste effectively and why that’s important.
  • Partner with schools, community gardens, farms, nonprofits, women’s groups, and other community organizations to promote composting and teach the importance of waste separation.
  • Create, support, or join certification programs that verify the quality of compost and/or verify food waste suppliers such as hotels, restaurants, and cafes.

Further information:

Investors
  • Ensure relevant portfolio companies separate waste streams, contribute to compost programs, and/or use finished compost.
  • Invest in companies developing composting programs or technologies that support the process, such as equipment, circular supply chains, and consumer products.
  • Fund start-ups or existing companies that are improving waste separation technology that enhances the quality of final compost products.
  • Offer financial services, including low-interest loans, microfinancing, and grants, to support composting initiatives.
  • Invest in companies that adhere to extended producer responsibility or encourage portfolio companies to adopt the policies.

Further information:

Philanthropists and International Aid Agencies
  • Help policymakers establish zero-waste and OW diversion goals; help incorporate them into local or national climate plans.
  • Advocate for businesses to establish time-bound and transparent zero-waste and OW diversion goals.
  • Advocate for extended producer responsibility approaches that hold producers accountable for waste.
  • Provide financing and capacity building for low- and middle-income countries to establish composting infrastructure and programs.
  • Help administer, fund, or promote composting programs.
  • Invest in companies developing composting programs or technologies that support the process, such as equipment, circular supply chains, and consumer products.
  • Fund startups or existing companies that are improving waste separation technology that enhances the quality of final compost products.
  • Incubate and fund mission-driven organizations and cooperatives that are advancing OW composting.
  • Offer financial services, including low-interest loans, microfinancing, and grants, to support composting initiatives.
  • Participate in consultations with farmers, policymakers, businesses, and the public to determine where to place plants, how to use compost, pricing, and how to roll out programs.
  • Work with farmers, local gardeners, the private sector, and local park systems to develop markets for compost.
  • Help ensure low- and middle-income households are served by composting programs, with particular attention to underserved communities such as multifamily buildings and rural households.
  • Advocate for laws or regulations that require waste separation as close to the source as possible, ensuring the rules are effective and practical.
  • Create demonstration projects to show the effectiveness and safety of finished compost.
  • Research and enact effective composting promotional strategies.
  • Establish one-stop-shop educational programs that use online and in-person methods to teach how to separate waste effectively and why that’s important.
  • Partner with schools, community gardens, farms, nonprofits, women’s groups, and other community organizations to promote composting and teach the importance of waste separation.
  • Create, support, or join certification programs that verify the quality of compost and/or verify food waste suppliers such as hotels, restaurants, and cafes.

Further information:

Thought Leaders
  • Participate in and promote centralized, community, or household composting programs, if available, and carefully sort OW from other waste streams.
  • If no centralized composting system exists, work with local experts to establish household and community composting systems.
  • Help policymakers establish zero-waste and OW diversion goals; help incorporate them into local or national climate plans.
  • Start cooperatives that provide services and/or equipment for composting.
  • Participate in consultations with farmers, policymakers, businesses, and the public to determine where to place plants, how to use compost, pricing, and how to roll out programs.
  • Help gather data on local OW streams, potential markets, and comparisons of alternative uses such as methane digesters.
  • Help develop waste separation technology that enhances the quality of final compost products and/or improve educational programs on waste separation.
  • Develop innovative governance models for local composting programs; publicly document your experiences.
  • Work with farmers, local gardeners, the private sector, and local park systems to develop markets for compost.
  • Advocate for extended producer responsibility approaches that hold producers accountable for waste.
  • Advocate for laws or regulations that require waste separation as close to the source as possible, ensuring the rules are effective and practical.
  • Create demonstration projects to show the effectiveness and safety of finished compost.
  • Create, support, or join certification programs that verify the quality of compost.
  • Research various governance models for local composting programs and outline options for communities to consider.
  • Research and enact effective composting campaign strategies.
  • Create, support, or join certification programs that verify the quality of compost and/or verify food waste suppliers such as hotels, restaurants, and cafes.

Further information:

Technologists and Researchers
  • Quantify estimates of OW both locally and globally; estimate the associated potential compost output.
  • Improve waste separation technology to improve the quality of finished compost.
  • Create tracking and monitoring software for OW streams, possible uses, markets, and pricing.
  • Research the application of AI and robotics for optimal uses of OW streams, separation, collection, distribution, and uses.
  • Research various governance models for local composting programs and outline options for communities to consider.
  • Research effective composting campaign strategies and how to encourage participation from individuals.

Further information:

Communities, Households, and Individuals
  • Participate in and promote centralized composting programs, if available, and carefully sort OW from other waste.
  • If no centralized composting system exists, work with local experts to establish household and community composting systems.
  • Participate in consultations with farmers, policymakers, and businesses to determine where to place plants, how to use compost, pricing, and how to roll out programs.
  • Take advantage of educational programs, financial incentives, employee benefits, and other programs that facilitate composting.
  • Advocate for extended producer responsibility approaches that hold producers accountable for waste.
  • Advocate for laws or regulations that require waste separation, ensuring the rules are effective and practical.
  • Partner with schools, community gardens, farms, nonprofits, women’s groups, and other community organizations to promote composting and teach the importance of waste separation.
  • Create, support, or join certification programs that verify the quality of compost and/or verify food waste suppliers such as hotels, restaurants, and cafes.

Further information:

Sources
Evidence Base

The scientific consensus on composting as a climate solution is high. Composting reduces OW, prevents pollution and GHG emissions from landfilled OW, and creates soil amendments that can reduce the use of synthetic fertilizers (Kaza et al., 2018; Manea et al., 2024). Although we do not quantify carbon sequestration from compost use in this analysis, a full life-cycle analysis that includes application could result in net negative emissions for composting (Morris et al., 2013).

Globally, the waste sector was responsible for an estimated 3.9% of total global GHG emissions in 2023, and solid waste management represented 36% of those emissions (IPCC, 2023; United Nations Environment Programme [UNEP], 2024). Emissions estimates based on satellite and field measurements from landfills or direct measurements of carbon content in food waste can be significantly higher than IPCC Tier 1-based estimates. Reviews of global waste management estimated that food loss and waste account for around 6% of global emissions or approximately 2.8 Gt CO₂‑eq/yr (Wilson et al., 2024; Zhu et al., 2023). Facility-scale composting reduces emissions 38–84% relative to landfilling (Perez et al., 2023), and monitoring and managing the moisture content, aeration, and carbon to nitrogen ratios can further reduce emissions (Ayilara et al., 2020).

Unclear legislation and regulation for MSW composting can prevent adoption, and there is not a one-size-fits-all approach to composting (Cao et al., 2023). Regardless of the method used, composting converts OW into a nutrient-rich resource and typically reduces incoming waste volumes 40–60% in the process (Cao et al., 2023; Kaza et al., 2018). A comparative cost and energy analysis of MSW components highlighted that while composting adoption varies geographically and economically, environmental benefits also depend on geography and income (Zaman, 2016). Food and green waste percentages of MSW are higher in lower-resourced countries than in high-income countries due to less packaging, and more than one-third of waste in high-income countries is recovered through recycling and composting (Kaza et al., 2018).

The results presented in this document summarize findings from 22 reports, 31 reviews, 12 original studies, two books, nine web articles, one fact sheet, and three data sets reflecting the most recent evidence for more than 200 countries and territories. 

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Appendix

Global MSW Generation and Disposal

Analysis of MSW in this section is based on the 2018 What a Waste 2.0 global dataset and report as well as the references cited in the report (Kaza et al., 2018; World Bank 2018). In 2018, approximately 2 Gt of waste was generated globally. Most of that went to landfills (41%) and open dumps (22%). Out of 217 countries and territories, 24 sent more than 80% of all MSW to landfills and 3 countries reported landfilling 100% of MSW. The average across all countries/territories was 28% of MSW disposed of in landfills. Both controlled and sanitary landfills with gas capture systems are included in the total landfilled percentage.

Approximately 13% of MSW was treated through recycling and 13% through incineration, but slightly more waste was incinerated than recycled per year. Incineration was predominately used in upper-middle and high-income countries with negligible amounts of waste incinerated in low- and lower-middle income countries.

Globally, only about 5% of MSW was composted and nearly no MSW was processed via methane digestion. However, OW made up nearly 40% of global MSW, so most OW was processed through landfilling, open dumping, and incineration all of which result in significant GHG emissions and pollution. There is ample opportunity to divert more OW from polluting disposal methods toward composting. Due to lack of data on open dumping, and since incineration only accounts for 1% of global GHG emissions, we chose landfilling as our baseline disposal method for comparison.

In addition to MSW, other waste streams include medical waste, e-waste, hazardous waste, and agricultural waste. Global agricultural waste generation in 2018 was more than double total MSW (Kaza et al., 2018). Although these specialized waste streams are treated separately from MSW, integrated waste management systems with high-quality source separation programs could supplement organic MSW with agricultural waste. Rather than being burned or composted on-farm, agricultural waste can provide bulking materials that are critical for maintaining moisture levels and nutrient balance in the compost pile, as well as scaling up composting operations. 

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Details of a Composting System and Process

Successful centralized composting starts with collection and separation of OW from other waste streams, ideally at the source of waste generation. Financial and regulatory barriers can hinder creation or expansion of composting infrastructure. Composting systems require both facilities and robust collection networks to properly separate OW from nonbiodegradable MSW and transport OW to facilities. Mixed waste streams increase contamination risks with incoming feedstocks, so separation of waste materials at the source of generation is ideal. 

Establishing OW collection presents a financial and logistical barrier to increased composting adoption (Kawai et al., 2020; Kaza et al., 2018). However, when considering a full cost-chain analysis that includes collection, transportation, and treatment, systems that rely on source-separated OW can be more cost-effective than facilities that process mixed organics. 

OW and inorganic waste can also be sorted at facilities manually or mechanically with automated techniques including electromagnetic separation, ferrous metal separation, and sieving or screening (Kawai et al., 2020). Although separation can be highly labor-intensive, it’s necessary to remove potential contaminants, such as plastics, heavy metals, glass, and other nonbiodegradable or hazardous waste components (Kawai et al., 2020; Manea et al., 2024). After removing contaminants, organic materials are pre-processed and mixed to achieve the appropriate combination of water, oxygen, and solids for optimal aerobic conditions during the composting process. 

Regardless of the specific composting method used, aerobic fermentation is achieved by monitoring and balancing key parameters within the compost pile. Key parameters are moisture content, temperature, carbon-to-nitrogen ratio, aeration, pH, and porosity (Cao et al., 2023; Kawai et al., 2020; Manea et al., 2024). The aerobic fermentation process can be split into distinct stages based on whether mesophilic (active at 20–40 oC) or thermophilic (active at 40–70 oC) bacteria and fungi dominate. Compost piles are constructed to allow for sufficient aeration while optimizing moisture content (50–60%) and the initial carbon-to-nitrogen ratio (25:1–40:1), depending on composting method and feedstocks (Amuah et al., 2022; Manea et al, 2024). Optimal carbon-to-nitrogen ratios are achieved through appropriate mixing of carbon-rich “brown” materials, such as sawdust or dry leaves, with nitrogen-rich “green” materials, such as food waste or manure (Manea et al., 2024). During the thermophilic stage, temperatures exceeding 62 oC are necessary to kill most biogenic pathogens and weed seeds (Amuah et al., 2022; Ayilara et al., 2020).

Throughout the composting process key nutrients (nitrogen, phosphorus, potassium, calcium, magnesium, and sodium), are mineralized and mobilized and microorganisms release GHGs and heat as by-products of their activity (Manea et al., 2024; Nordahl et al., 2023). Water is added iteratively to maintain moisture content and temperature in the optimal ranges, and frequent turning and aeration are necessary to ensure microorganisms have enough oxygen. Without the proper balance of oxygen and water, anaerobic conditions can lead to higher methane emissions (Amuah et al., 2022; Manea et al., 2024). Although CO₂, methane, and nitrous oxide are released during the process, these emissions are significantly lower than associated emissions from landfilling (Ayilara et al., 2020; Cao et al., 2023; FAO, 2019; Perez et al., 2023).

Once aerobic fermentation is completed, compost goes through a maturation stage where nutrients are stabilized before finished compost can be sold or used as a soil amendment. In stable compost, microbial decomposition slows until nutrients no longer break down, but can be absorbed by plants. Longer maturation phases reduce the proportion of soluble nutrients that could potentially leach into soils. 

The baseline waste management method of landfilling OW is cheaper than composting; however it also leads to significant annual GHG emissions. Composting, although more expensive due to higher labor and operating costs, reduces emissions and produces a valuable soil amendment. Establishing a composting program can have significant financial risks without an existing market for finished compost products (Bogner et al., 2007; Kawai et al., 2020; UNEP, 2024).

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Example Calculation of Achievable Adoption

In 2018, Austria had the highest composting rate of 31.2%, and Vietnam composted 15% of MSW (World Bank, 2018). 

For low adoption, we assumed composting increases by 25% of the existing rate or until all OW in MSW is composted. In Austria, OW made up 31.4% of MSW in 2018, so the Adoption – Low composting rate was 31.4%. In Vietnam, the Adoption – Low composting rate came out to 18.75%, which is still less than the total OW percentage of MSW (61.9%).

For high adoption, we assumed that composting rates increase by 50% of the existing rate or until all OW in MSW is composted. So high adoption in Austria remains 31.4% (i.e., all OW generated in Austria is composted). In Vietnam, the high adoption composting rate increases to 22.5% but still doesn’t capture all OW generated (61.9% of MSW).

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