What is our assessment?

Based on our analysis, we find that fishing vessel efficiency improvements are ready to deploy and feasible, but probably have limited climate impact because the wild capture fisheries sector contributes a relatively small share of global GHG emissions. These improvements will likely provide long-term cost savings and added benefits for ecosystems and air quality. We conclude this climate solution is “Worthwhile.”

What is it?

Improving fishing vessel efficiency reduces CO₂ emissions by using gear, vessel, or operational changes that lower fuel use in wild capture fisheries. Vessel upgrades include propulsion-related changes, such as installation of more efficient engines, and non-propulsion-related alterations, such as modified bows and hulls that reduce drag. Changing to low-fuel-use gear to catch fish, when and where possible, can also reduce CO₂ emissions. Operational changes, such as speed reductions or route optimization, can likewise lead to more efficient fuel use.

Does it work?

Vessel efficiency improvements are expected to deliver substantial fuel savings. An estimated 60–90% of emissions in wild capture fisheries, which emit roughly 0.18 Gt CO₂‑eq/yr in total, likely result from fuel consumption. Speed reductions alone can reduce fuel use by up to 30%. Vessel modifications could provide fuel savings of up to 20% in small fishing vessels, which comprise roughly 86% of all motorized fishing vessels globally. Upgrading engines and other propulsion-related equipment can reduce fuel use by up to 30%. Gear switching, when viable, can also be highly effective at improving fuel use efficiency, particularly if the target species are typically caught using methods such as trawling, which has a high carbon footprint. 

Why are we excited?

The average emissions per metric ton of landed fish in wild capture fisheries have grown by over 20% since 1990, highlighting the need for efficiency improvements. Many of these improvements can be implemented without sacrificing fishing effort or opportunities, and some operational changes, such as reducing vessel speed, can be done without any new equipment. All changes reduce fuel use, saving fishers money over time and likely resulting in fewer emissions of harmful air pollutants, such as sulfur oxides and black carbon. Some upgrades could deliver additional benefits to air quality and ocean ecosystems. Cleaner engines can further reduce air pollution through more complete combustion of fuel, and gear changes could benefit seafloor ecosystems, which can be damaged from bottom fishing practices, such as trawling and dredging. Additionally, some fishing gear has high bycatch rates, and switching to gear that allows for more exclusive capture of target species can reduce waste.

Why are we concerned?

Even with widespread adoption, efficiency improvements that reduce fuel use are unlikely to have a major climate impact. Efficiency improvements could also inadvertently encourage increases in fishing effort, which would increase fuel use and offset emissions cuts. Initial costs to upgrade can be highly variable, but might be high in some cases and therefore not feasible for some fishers. Gear switching can result in lower fish catches, as some methods might not be as efficient. Some operational changes, such as reducing speeds, could lead to fishers arriving at fishing grounds late.

What is our assessment?

While Improve Aquaculture is unlikely to have a major climate impact, our assessment concludes that it is “Worthwhile” due to its ability to reduce pressure on wild fish stocks and terrestrial biomass, and because efficiency improvements made now are likely to scale into greater climate impact as the sector continues to expand.

What is it?

GHG emissions from aquaculture can be reduced by increasing the feed conversion efficiency of the cultured animals and decarbonizing on-farm energy use. Aquaculture – farming aquatic animals or plants for food or other purposes – is rapidly growing and now accounts for over half of the global production of aquatic animals, exceeding wild capture fisheries. Over 7% of human-consumed protein is aquaculture-produced. As this sector has grown, it has become increasingly reliant on external feed sources, with the share of non-fed aquaculture (e.g., bivalves that feed from the water column) dropping from nearly 40% in 2000 to 27% in 2022. Improving feed conversion ratios (FCR) – the amount of feed it takes to produce a given amount of biomass – can lower feed demand and reduce CO₂ and other GHG emissions tied to feed production and transport. FCRs can be improved by feed formulations that increase digestibility, genetic or breeding modifications to improve digestive efficiency in the cultured animal, species-specific feed formulations, and optimizing ration size and feeding frequency. At the same time, decarbonizing on-farm energy use can help reduce CO₂ emissions from common equipment, such as aerators and water pumps.

Does it work?

Interventions to improve feed and energy efficiency can reduce CO₂ emissions from aquaculture operations, although the potential achievable climate impact of these actions is currently unlikely to be globally meaningful (>0.1 Gt CO₂‑eq/yr ). Total annual emissions from aquaculture were estimated to be 0.26 Gt CO₂‑eq/yr in 2017, with nearly 60% of that attributed to feed production. Improving FCR is both plausible and effective, since it directly reduces the amount of food needed to cultivate fish and other species, thereby lowering emissions tied to feed production and transport. Between 1995 and 2007, improvements in FCR have ranged between 5 to 15% for a variety of species, including shrimp, salmon, carp, and tilapia.

Decarbonizing on-farm energy use can reduce equipment-related emissions, particularly in intensive systems that use energy for automated feeding systems, water temperature control, and circulation and aeration systems. In general, the potential impact of decarbonizing varies widely because on-farm energy use differs significantly across species and production systems. For instance, shrimp and prawn farming use nearly 20,000 MJ/t of live weight (LW), with over 75% from electricity, while bivalve production uses around 3,000 MJ/t of LW supplied largely by diesel.

Why are we excited?

Improving feed efficiency in aquaculture reduces demand for captured wild fish used in feed, reducing pressure on overfished stocks. It also lowers reliance on terrestrial biomass, such as soy, wheat, and rice, which come with additional land-use and emission costs. More efficient feeding can help reduce nutrient pollution, which can be responsible for high methane and nitrous oxide fluxes in some inland aquaculture systems. At the same time, decarbonizing on-farm energy use might ultimately lead to lower long-term operating costs and improved energy reliability.

Why are we concerned?

There are relatively few drawbacks associated with improving aquaculture. In the case of decarbonizing on-farm energy use, upfront costs could be high. For instance, installing solar panels or upgrading pumps can be financially challenging for small-scale operations. Energy use on farms can also vary throughout the day and night, which might not always align with renewable energy sources, like solar, without storage. While this solution focuses on reducing GHG emissions from existing aquaculture practices, it is important to recognize that aquaculture can be environmentally harmful and that impacts vary widely depending on how it is done, where it occurs, and which species are being cultivated.

What is our assessment?

Based on our analysis, the climate impact of restoring seaweed ecosystems is unclear but likely to be low. While restoration offers important ecological benefits, its effectiveness in removing carbon is understudied, and the implementation costs may be prohibitively high, but require further research. Therefore, we conclude that Restore Seaweed Ecosystems is a “Worthwhile” solution.

What is it?

Seaweed ecosystem restoration is the deliberate action of reestablishing seaweed in degraded, damaged, or destroyed ecosystems. Seaweed removes CO₂ from seawater through photosynthesis, which allows the ocean to absorb additional CO₂ from the atmosphere. Some of the fixed carbon can be sequestered through export to the deep sea or burial at the seafloor, while a portion may also persist as carbon forms that resist degradation even in the surface ocean. Restoration of seaweed ecosystems helps restore biomass and therefore the productivity of these ecosystems, which can enhance their sequestration capacity. Restoration can occur in a number of ways, but commonly includes transplanting adults, controlling grazers, building artificial reefs, seeding with propagules or spores, remediating pollution, removing competitive species, and culturing. Most restoration efforts have focused on canopy-forming species, such as giant kelp (Macrocystis pyrifera). 

Does it work?

Seaweed ecosystem restoration can be somewhat effective, with nearly 60% of restoration efforts achieving survival rates of over 50%. The first large-scale restoration is thought to have occurred in Japan in the late 1800s. Still, few projects have been implemented at scale, with most restoration efforts below 0.1 ha in size. Moreover, little data exist to evaluate the effectiveness of restored seaweed ecosystems at removing carbon. While theoretically, they should regain functional equivalence to intact systems, this requires further research. The extent of lost and degraded seaweed ecosystems is also poorly understood, making it unclear how restoration efforts might be scaled globally. Additionally, the air-to-sea transfer of CO₂ to replace the CO₂ taken up by photosynthesis in the ocean is not always efficient, meaning removal in the water column may not always translate to equivalent atmospheric CO₂ removal. However, this aspect of effectiveness also remains understudied. Consequently, the climate impact of restoration is uncertain.

Why are we excited?

Healthy seaweed ecosystems provide a range of ecological benefits. Seaweed can help buffer against ocean acidification in some places as functional systems better regulate pH. These systems also provide complex habitats that support a wide range of marine life, such as fish and invertebrates, so restoring seaweed ecosystems can help recover biodiversity. Seaweed ecosystem restoration can also improve nutrient cycling and overall ecosystem resilience to climate stressors.

Why are we concerned?

Restoration of seaweed ecosystems is currently expensive, with costs varying widely depending on the method used. In kelp forests, chemical or manual urchin removal, which reduces grazing pressure, may cost between US$1,700/ha and US$76,000/ha in 2023 dollars, while most other approaches exceed US$590,000/ha.

It’s also unclear whether seaweed restoration efforts could scale enough to have a globally meaningful impact on GHG emissions. Using estimates from intact subtidal brown seaweed ecosystems, which are among the most productive and represent a likely upper limit on the effectiveness of seaweed restoration as a whole, restoration might remove 2.3 tCO₂‑eq /ha/yr. At this rate, over 40 Mha would need to be restored to exceed 0.1 GtCO₂‑eq/yr. However, most restoration projects are under 0.1 ha. For kelp forests, only roughly 2% (19,000 ha) have been restored out of the Kelp Forest Challenge’s target of 1 million ha by 2040, suggesting that this practice may not be scalable currently.

The effectiveness of restoration can also be offset by the life-cycle emissions of products required to re-establish some seaweed ecosystems. For example, emissions from the production of cement blocks needed to afforest some seaweed habitats have been estimated to potentially delay carbon removal benefits for 5–13 years in some systems.

What is our assessment?

Based on our analysis, boosting appliance and equipment efficiency is a promising strategy for reducing GHG emissions, but significant leaps in efficiency and shifts in user behavior are needed to counteract the rebound effect and realize its impact. This potential climate solution is “Worthwhile.”

What is it?

Appliance and equipment efficiency typically refers to larger devices in residential buildings that run on electricity, such as refrigerators, freezers, washing machines, dishwashers, dryers, and televisions. Energy-efficient appliances or equipment consume less electricity when operated than do inefficient devices. Therefore, boosting appliance efficiency reduces the CO₂, methane, and nitrous oxide emissions from electricity generation. As of 2022, the energy consumed by household appliances globally was more than twice the total energy used to cool both residential and nonresidential buildings, and about half the energy used for heating. To drive higher efficiency for these devices, various countries have established regional energy efficiency standards, rating systems, and labeling programs. Currently, homeowners can readily access a variety of options on the appliance market, and less efficient devices can easily be replaced. However, income levels, especially in low- and middle-income countries, may affect people’s actual ability to purchase certain appliances, although these devices are increasingly becoming cheaper.

Does it work?

Improving the efficiency of appliances and equipment functionally reduces the energy required to run these devices. Various field studies have demonstrated the effect of efficiency gains on lowering electricity consumption. However, the rise in appliance ownership per household and the growing total number of households have offset the collective climate impact expected from efficiency improvements. Globally, the number of households grew from about 1.5 billion in 2000 to 2.2 billion in 2021. Considering the concurrent increase in the global average units owned per household, the number of appliances in use has essentially doubled over the same period. For example, we estimate that over two decades, the number of televisions owned grew from about 1.4 to 2.8 billion units, refrigerators grew from 0.9 to 1.7 billion units, and washing machines grew from about 0.6 to 1.1 billion units. This growth resulted in rising electricity consumption by appliances annually, from 2,880 TWh in 2000 to 5,734 TWh in 2022, which translates to a 99% global increase, largely driven by the Asia-Pacific region.

Why are we excited?

Boosting appliance and equipment efficiency allows homeowners to realize operational cost savings as a result of lower electricity consumption and utility bills. Compared with less efficient devices, using appliances with higher efficiency ratings functionally reduces peak electricity demand, alleviating strain on the electric grid. The advent of smart devices and the Internet of Things (IoT) also helps to automate the operation of these appliances, optimizing their runtime while minimizing the energy consumed. Initial purchasing costs are also declining, making efficient appliances more accessible and affordable. 

Access to high-efficiency appliances also yields additional benefits. For example, access to energy-efficient refrigerators and freezers means that food waste can be minimized with less energy, leading to better food security. Similarly, multimedia equipment, such as television sets, offers access to critical information. Further cuts in GHG emissions are also possible as the electric grid transitions to renewable energy sources.

Why are we concerned?

Despite the potential benefits, the efficiency improvements in household appliances and equipment have not effectively translated into a positive climate impact. This is largely due to the significant rebound effect, or the increase in appliances owned by households as these devices become cheaper and more efficient. Considering the role of appliances in providing a greater quality of life, limiting the increase in appliance purchases is dismissible. The markets for appliances and equipment in many countries also still consist of pre-owned devices, which are less efficient. Some countries, such as Ghana, have established legislation to prevent the importation of pre-owned devices. This approach ensures that the appliances bought by homeowners will run on the newest, most efficient technologies. Recent findings from regions with stringent energy rating systems also suggest that regulations and programs can lead to a 50% cut in the electricity consumed by appliances. Global initiatives, such as the United for Efficiency (U4E) partnership, which seeks to shift appliance markets in low- and middle-income countries into high-efficiency devices, are increasingly needed for the potential energy savings to be realized as a climate solution.

What is our assessment?

Based on our analysis, using low-flow fixtures is a cost-effective strategy for reducing water consumption, but has only a modest impact on GHG emissions. Therefore, this climate solution is “Worthwhile.”

What is it?

Low-flow fixtures lessen the total consumption of water by reducing flow rates through a household faucet or shower. Less hot water use means fewer emissions from the energy source used to heat the water, and it also means fewer emissions from pumping and treating tap water. Heating water for showers, sinks, and other domestic appliances is often the second largest source of emissions from buildings after space heating. Modern low-flow showerheads can produce comparable pressure and coverage to traditional showerheads through aeration and/or laminar flow. Aerators for faucets and low-flow showerheads are relatively low-cost investments that users can install themselves.

Does it work?

Low-flow fixtures reduce emissions from heating, delivering, and treating water by reducing hot water consumption. There is ample evidence for water savings with low-flow fixtures, as well as for the linkage between quantity and source of energy used for water heating and GHG emissions. Additionally, there is substantial research on the emissions from treating and pumping water, which can be reduced through water conservation. Low-flow fixtures are readily available, and performance labels are available to help consumers select quality products.

Why are we excited?

Low-flow fixtures conserve water, which reduces emissions, reduces energy demand, saves consumers money, and helps with sustainable water resource management. Households that adopt low-flow fixtures can enjoy significant utility bill savings because these fixtures reduce both water consumption and the energy used to heat water in the home. Faucet aerators also produce a smoother water stream with less splashing, and along with low-flow showerheads, are low-cost and simple to install. Household water conservation practices, such as low-flow fixtures, can help with regional sustainable water resource management and defer infrastructure expansion projects. This is particularly important in areas where water resources are increasingly strained due to climate change, growing populations, and other factors. In some regions, community water conservation efforts have had measurable impacts on water treatment costs, resulting in lower water rates for consumers.  

Why are we concerned?

Even with widespread adoption, low-flow fixtures would have a relatively small impact on GHG emissions. Moreover, the low cost and ease of replacement mean that low-flow fixtures can be easily reverted to less efficient fixtures, eliminating the emissions impact and other benefits. Lastly, although modern quality low-flow showerheads are comparable to traditional fixtures, the poor quality of early low-flow showerheads may have contributed to decreasing levels of adoption in some areas.

What is our assessment?

Based on our analysis, restoring salt marsh ecosystems is a “Worthwhile” carbon removal technique that is ready for large-scale deployment. While the capacity for adoption is limited, limiting climate impact, this solution has no major risks and provides widespread added benefits for people and the environment.

What is it?

Restore Salt Marsh Ecosystems removes carbon from the air by reestablishing salt marshes in areas where they were previously drained, filled, or otherwise degraded and lost. As plants take up CO₂ through photosynthesis and vegetation traps sediments, some of this carbon is stored long term in waterlogged soils with slow decomposition rates. Restoration typically reconnects land to tidal exchange and rebuilds marsh elevation and vegetation, which promotes plant growth and sediment accumulation. Active restoration can include breaching levees or removing barriers to restore tidal flow, regrading or adding sediment to raise elevations, planting native marsh vegetation, and controlling invasive species. In many cases, restoration can also reduce GHG emissions by replacing land uses, such as drained agriculture, that emit CO₂.

Does it work?

The fundamental idea of restoring salt marsh ecosystems is scientifically sound, and, on average globally, restored salt marshes have been shown to remove carbon over long timescales through vegetation recovery and sustained carbon burial in waterlogged soils, even after accounting for methane and nitrous oxide emissions. This solution has been in practice worldwide for many decades, and global assessments suggest it could expand to roughly 2 million hectares because ~67% of salt marshes have been destroyed since the early 1900s. Restoration success rates are high relative to those of many other marine habitats. However, its potential adoption ceiling is still low relative to other nature-based solutions (e.g., Restore Forests) because restoration is limited to suitable coastal areas, which are constrained by coastal development and other human stressors. As a result, its climate impact is likely well below 0.1 Gt CO₂‑eq /year. 

Why are we excited?

Restoration of salt marsh ecosystems is a well-established, scalable practice with many benefits for the environment. Restored salt marshes can reduce shoreline erosion and costal flooding, improve water quality by retaining nutrients and sediments, and provide habitat for fish and birds. While global impact is limited, this intervention can be an important multi-benefit tool for building climate resilience and removing carbon in some countries and coastal regions. Restoration is already widely implemented. In some restorations, such as those that reestablish tidal exchange in previously impounded ecosystems, increases in salinity can reduce methane and nitrous oxide production relative to pre-restoration conditions.

Why are we concerned?

The climate impact of salt marsh restoration is constrained by its limited adoption ceiling, variable but potentially high costs, vulnerability to future loss, and potentially low effectiveness. Adoption is limited by where marshes can actually be restored, such as on low-elevation coastal lands that are not heavily developed, and where they can be maintained into the future with climate change stressors, such as sea-level rise. If salt marshes are not restored with consideration of projected sea level rise, loss or conversion to mud flats or open water habitats in the future is possible, which would result in the loss of carbon benefits. Restored salt marshes can also emit potent GHGs such as methane and nitrous oxide as low oxygen conditions and ecosystem function are reestablished, which can offset some of the climate benefits of restoration. As a result, costs vary widely by site, and can exceed US$500/t CO₂‑eq (~US$1,000–7,000/ha), depending on site-specific effectiveness rates. Additionally, few data are available for understanding long-term, multi-decadal changes in carbon accumulation rates in restored sites, and some regions remain underrepresented globally.

What is our assessment?

Based on our analysis, grassland and savanna restoration is a promising climate solution, but there is insufficient evidence to ascertain how much carbon it could remove at the global scale. Restoring Grasslands and Savannas is therefore “Worthwhile.” 

What is it?

Restoring grasslands and savannas removes carbon from the atmosphere via photosynthesis and stores it in soils and vegetation. Grassland and savanna restoration includes a spectrum of practices, such as returning ecologically appropriate grazing and fire regimes, reseeding with native species, and controlling invasive and woody plants. 

Because grasslands and savannas are diverse, widespread ecosystems spanning a large climatic range, appropriate restoration and management strategies vary depending on the type of degradation and the natural history of the area. For this solution, we considered only degraded areas that were historically grassland and savanna and are not currently used as croplands or grazing lands. Other Project Drawdown solutions, including Deploy Silvopasture, Reduce Grazing Intensity, and Deploy Alternative Grazing, address increasing carbon removal in grasslands managed for grazing. Protect Grasslands & Savannas addresses protecting existing carbon stocks by reducing ongoing ecosystem degradation.

Does it work?

Grassland and savanna restoration will generally remove carbon when implemented with ecologically appropriate strategies on grasslands and savannas with depleted carbon stocks. Restoration efforts covering millions of hectares have already been initiated in some regions, though data tracking restoration progress are sparse. Although grassland and savanna restoration will remove carbon in principle, very little information is available to quantitatively assess the amount of carbon removed by restoration of degraded, ungrazed grasslands and savannas. One study in the United States found that planting diverse species on degraded grasslands increased total carbon uptake by up to 178% of that associated with natural succession over 22 years; however, the generalizability of this finding is unclear. Other studies that focused on activities outside of the scope of this solution, such as changing grazing practices, restoring croplands to grasslands, planting legumes, and adding fertilizers, found an average increase in carbon uptake rates of ~1.7 t CO₂‑eq /ha/yr with a range of 0.1–3.2 t CO₂‑eq /ha/yr. These estimates may serve as a rough benchmark of the maximum per-hectare carbon removal that grassland restoration could achieve.

Why are we excited?

Grassland and savanna restoration may be an effective, low-risk strategy for sequestering carbon on hundreds of millions of hectares while also providing substantial benefits for biodiversity and other ecosystem services. Grasslands and savannas are the largest ecosystem on Earth, covering more than 2.8 billion hectares (see Protect Grasslands & Savannas) from the tropics to the tundra. Some studies estimate that roughly half of grasslands are degraded, suggesting that the opportunity for grassland and savanna restoration is in the range of hundreds of millions of hectares even after excluding grazed areas. Grasslands and savannas also play a critical role in the global carbon cycle, containing roughly 30% of the world’s soil carbon stock. Therefore, even small relative increases in grassland and savanna carbon stocks could translate into large absolute climate benefits. Because most grassland and savanna carbon is stored in below-ground biomass and soils, these carbon stocks can be more resilient to disturbance, such as fire, than carbon stored in above-ground biomass. 

In addition to the potential climate benefits, healthy grasslands and savannas support diverse biological communities, regulate hydrology, improve water quality, reduce erosion, and provide pollination, cultural, and provisioning services to local communities. 

Why are we concerned?

While grassland and savanna restoration can consistently remove carbon, large uncertainties remain in the magnitude of the effectiveness and adoption potential of this solution. 

First, most research on the carbon removal potential of grasslands and savannas focuses on improving grazing management or conversion of croplands back to grasslands, which are outside the scope of this solution. Effectiveness at removing carbon also depends on post-restoration management because many grasslands and savannas depend on establishment of ongoing, ecologically appropriate fire and grazing regimes. Additionally, climate change is reducing grassland and savanna productivity in many regions and may prohibit successful restoration in some places. 

Second, the area of degraded, ungrazed grasslands and savannas that are restorable remains largely unknown. The definition of land degradation varies across studies, and maps of degraded lands are inconsistent with one another. While maps of grazing extent have improved, they are still uncertain. Thus, it is difficult to assess the adoption potential of this solution. Without sufficient data on effectiveness and adoption potential, we are ultimately unable to assess whether the climate impact of this solution falls above or below our threshold of 0.1 Gt CO₂‑eq/yr. We encourage additional research to alleviate data limitations related to grassland and savanna restoration.

What is our assessment?

Our analysis concludes that, despite its limited global impact for reducing emissions, Reduce Overfishing is a “Worthwhile” climate solution that has other important benefits for ecosystem health and long-term food security.

What is it?

Reducing overfishing lowers fuel use and CO₂ emissions from wild capture fishing vessels by reducing fishing effort on overfished stocks. This is typically achieved through management actions, such as seasonal closures, gear restrictions, and catch limits. Fishing effort, whether measured as the hours spent fishing or distance traveled, is generally proportional to fuel use. In addition to immediate reductions in emissions, reducing overfishing can allow overfished stocks to recover, which can lead to reduced future emissions since fuel use is lowered when fish are easier to catch and harvested sustainably.

Does it work?

Reducing fishing effort in locations with depleted and overfished wild fish stocks is expected to reduce emissions from fishing vessels. When stocks are overfished, fishers must exert additional effort, traveling further and/or searching longer to make the same catch, which increases fuel use and CO₂ emissions. Reducing overfishing through management actions, such as harvest control rules, gear restrictions, seasonal closures, stronger enforcement of existing regulations, and establishment of marine protected areas, can help fish stocks recover. Other policy tools, such as reducing harmful fuel subsidies that currently enable many otherwise unprofitable fishing fleets, are also likely to result in lower fuel use and CO₂ emissions. Healthy fish stocks can be caught with lower fishing effort, translating to future fuel savings and reduced CO₂ emissions. Global estimates suggest that reductions in overfishing could avoid up to 0.08 Gt CO₂‑eq/yr, representing almost half of the entire capture fisheries sector's annual emissions (0.18 Gt CO₂‑eq/yr ).

Why are we excited?

Currently, overfishing affects more than 35% of global wild marine fish stocks, increasing by 1%, on average, every year. Reducing overfishing not only lowers fuel use and emissions but also allows overfished stocks to recover. Healthy fish stocks strengthen marine food webs and contribute to ecosystem resilience and biodiversity. Overfishing has widespread consequences for diverse marine ecosystems, such as kelp forests, where declines in fish have led to overgrazing of the kelp by sea urchins. Over time, management interventions will also likely improve the sustainability and long-term reliability of coastal livelihoods and food security by supporting sustainable fisheries.

Why are we concerned?

Policy and management tools for reducing overfishing and, by extension, fishing-related emissions come with some challenges. For instance, management measures or legal protections may not be fully effective if implementation or enforcement is weak. Management and enforcement can be particularly challenging on the high seas, where jurisdiction is limited or shared across many nations, and where illegal, unreported, and unregulated fishing can be widespread. Even when effective, fish stock recovery can take years to decades, and the costs and trade-offs are unlikely to be evenly distributed across fishing fleets. In the short term, efforts to reduce overfishing could create economic challenges for small-scale fishers who may have fewer resources and less capacity to adapt to management restrictions.