Cut Emissions FALO & Nature-Based Carbon Removal Protect & Manage Ecosystems

Protect Coastal Wetlands

Highly Recommended
Worthwhile
Birds flying over wetland

Coastal wetland protection is the long-term protection of mangrove, salt marsh, and seagrass ecosystems from degradation by human activities. This solution focuses on legal mechanisms of coastal wetland protection, including the establishment of Protected Areas (PAs) and Marine Protected Areas (MPAs), which are managed with the primary goal of conserving nature. These legal protections reduce a range of human impacts, helping to preserve existing carbon stocks and avoid CO₂ emissions.

Last updated September 17, 2025

Solution Basics

ha protected

t CO₂-eq (100-yr)/unit/yr
07.647.88
units
Current 2.94×10⁶ 07.85×10⁶1.1×10⁷
Achievable (Low to High)

Climate Impact

Gt CO₂-eq (100-yr)/yr
Current 0.02 0.060.09
US$ per t CO₂-eq
1
Emergency Brake

CO₂

Solution Basics

ha protected

t CO₂-eq (100-yr)/unit/yr
04.384.78
units
Current 1.24×10⁶ 03.75×10⁶5.25×10⁶
Achievable (Low to High)

Climate Impact

Gt CO₂-eq (100-yr)/yr
Current 0.01 0.020.03
US$ per t CO₂-eq
2
Emergency Brake

CO₂

Solution Basics

ha protected

t CO₂-eq (100-yr)/unit/yr
03.153.56
units
Current 3.86×10⁶ 01.57×10⁷2.2×10⁷
Achievable (Low to High)

Climate Impact

Gt CO₂-eq (100-yr)/yr
Current 0.01 0.060.08
US$ per t CO₂-eq
-6
Emergency Brake

CO₂

Additional Benefits

180
183,184,188
    183
    • 184
    • 185
    • 186
    • 187
    • 188
189,191,193

Overview

Coastal wetlands (defined as mangrove, salt marsh, and seagrass ecosystems, see Figure 1) are highly productive ecosystems that sequester carbon via photosynthesis, storing it primarily below ground in sediments where waterlogged, low-oxygen conditions help preserve it (Adame et al., 2024; Lovelock et al., 2017). 

Figure 1. Types of coastal wetlands, from left to right: a salt marsh in Westhampton Beach (United States), a mangrove forest near Staniel Cay (Bahamas), and a seagrass meadow off Notojima Island (Japan).

Types of wetlands

Adobe Stock | istock; Maria T Hoffman | Adobe Stock; James White and Danita Delimont | AdobeStock

These ecosystems are also efficient at trapping carbon suspended in water, which can comprise up to 50% of the carbon sequestered in these settings (McLeod et al., 2011; Temmink et al., 2022). Coastal wetlands operate as large carbon sinks (Figure 2), with long-term carbon accumulation rates averaging 5.1–8.3 t CO₂‑eq /ha/yr (McLeod et al., 2011).

Figure 2. Overview of carbon storage in coastal wetlands. Salt marshes, mangroves, and seagrasses, commonly referred to as blue carbon ecosystems, store carbon in plant biomass and sediment.

Diagram demonstr ating CO2 absorption in salt marsh, mangroves, and seagrass.

Source: Macreadie, P. I., Costa, M. D., Atwood, T. B., Friess, D. A., Kelleway, J. J., Kennedy, H., ... & Duarte, C. M. (2021). Blue carbon as a natural climate solution. Nature Reviews Earth & Environment, 2(12), 826-839. Link to source: https://doi.org/10.1038/s43017-021-00224-1

Protection of coastal wetlands preserves carbon stocks and avoids emissions associated with degradation, which can increase CO₂, methane, and nitrous oxide effluxes. Nearly 50% of the total global area of coastal wetlands has been lost since 1900 and up to 87% since the 18th century (Davidson, 2014). With current loss rates, an additional 30–40% of remaining seagrasses, salt marshes, and nearly all mangroves could be lost by 2100 without protection (Pendleton et al., 2012). Protection of existing coastal wetlands is especially important because restoration is challenging, costly, and not yet fully optimized. For example, seagrass restoration has generally been unsuccessful (Macreadie et al., 2021), and restored seagrass systems can have higher GHG fluxes than natural systems (Mason et al., 2023).

On land, degradation often arises from aquaculture, reclamation and drainage, deforestation, diking, and urbanization (Mcleod et al., 2011). In the ocean, impacts often occur due to dredging, mooring, pollution, and sediment disturbance (Mcleod et al., 2011). For instance, deforestation of mangroves for agriculture removes biomass and oxidizes sediment carbon stocks, leading to high CO₂ effluxes and, potentially, methane and nitrous oxide emissions (Chauhan et al., 2017, Kauffman et al., 2016, Sasmito et al., 2019). Likewise, high CO₂ or methane effluxes from salt marshes commonly result from drainage, which can oxygenate the subsurface and fuel carbon loss, or from infrastructure such as dikes, which can reduce saltwater exchange and increase methane production (Kroeger et al., 2017). In another example, dredging in seagrass meadows drives high rates of ecosystem degradation due to reduced light availability, leading to die-offs that can increase erosion and reduce sediment carbon stocks by 21–47% (Trevathan-Tackett et al., 2018).

Our analysis focused on the avoided CO₂ emissions and retained carbon sequestration capacity conferred by avoiding degradation of coastal wetlands via legal protection. While degradation can substantially alter emissions of other GHGs, such as methane and nitrous oxide, we focus on CO₂ due to the limited availability of global spatial data on degradation types and extent and associated effluxes of all GHGs across coastal wetlands. Ignoring methane and nitrous oxide benefits with protection is the most conservative approach because limited data exist on emission profiles from both functional and degraded global coastal wetlands, and even PAs/MPAs can be degraded (Holmquist et al., 2023). This solution considered wetlands to be protected if they are formally designated as PAs or MPAs under International Union for Conservation of Nature (IUCN) protection categories I–IV (UNEP-WCMC &IUCN, 2024; see Appendix for more information).

Impact Calculator

Adjust effectiveness and adoption using range sliders to see resulting climate impact potential.

Effectiveness

7.88
t CO2-eq/ha/yr
25th
percentile
7.64
75th
percentile
9.81
7.88
median

Adoption

2.94×10⁶
ha protected
Low
7.85×10⁶
High
1.1×10⁷
2.94×10⁶
current
Achievable Range

Climate Impact

0.02
Gt CO₂-eq/yr (100-yr)
05
which is the equivalent of
0.04%
of global emissions
Adjust effectiveness and adoption using range sliders to see resulting climate impact potential.

Effectiveness

4.78
t CO2-eq/ha/yr
25th
percentile
4.38
75th
percentile
5.2
4.78
median

Adoption

1.24×10⁶
ha protected
Low
3.75×10⁶
High
5.25×10⁶
1.24×10⁶
current
Achievable Range

Climate Impact

0.01
Gt CO₂-eq/yr (100-yr)
05
which is the equivalent of
0.01%
of global emissions
Adjust effectiveness and adoption using range sliders to see resulting climate impact potential.

Effectiveness

3.56
t CO2-eq/ha /yr
25th
percentile
3.15
75th
percentile
4.27
3.56
median

Adoption

3.86×10⁶
ha protected
Low
1.57×10⁷
High
2.2×10⁷
3.86×10⁶
current
Achievable Range

Climate Impact

0.01
Gt CO₂-eq/yr (100-yr)
05
which is the equivalent of
0.02%
of global emissions

Maps

The current adoption, potential adoption, and effectiveness of coastal wetland protection is ecosystem-dependent (mangroves, salt marshes, seagrasses) and geographically variable. While coastal wetland protection can help avoid GHG emissions anywhere they occur, ecosystems with high rates of loss from human activity, and large unprotected areas have the greatest potential for avoiding emissions via protection. 

For instance, seagrass ecosystems have the lowest current adoption of protection, ~12%, and highest adoption ceiling (31.4 Mha) (Tables 3 and 6). Protecting seagrasses also potentially can save money (–US$23/ha, Table 2) because they do not generally require land purchase (McCrea-Strub et al., 2011). Protection of seagrasses could therefore provide meaningful climate impact as well as substantial economic and ecologic benefits (Unsworth et al., 2022). 

For seagrasses, countries like Australia (~10 Mha), Indonesia (~3 Mha), the United States (~0.5 Mha), and regions such as the Gulf of Mexico (~2 Mha) and the Western Mediterranean (~0.4 Mha), could be good initial targets for protection due to their significant seagrass extents (Green and Short, 2003). Countries that contain the top 10 largest areas of mangroves (Australia, Bangladesh, Brazil, India, Indonesia, Malaysia, Mexico, Myanmar, Nigeria, Papua New Guinea) might have the greatest potential to significantly expand adoption and scale climate impact (Dabalà et al., 2023). Likewise, salt marsh protection might be most beneficial in countries with the greatest extent, such as the United States (~1.7 Mha), Australia (~1.3 Mha), Russia (~0.7 Mha), and China (~0.6 Mha) (Mcowen et al., 2017).

% mangroves
> 0100

Global mangrove ecosystem distribution

Mangrove ecosystems cover approximately 15.7 million ha globally; just five countries (Australia, Brazil, Indonesia, Mexico, and Nigeria) contain nearly 50% of the world’s mangrove ecosystem area (FAO, 2020). Green shaded areas indicate the general location of mangrove ecosystems; zoom in for details.

Liu, L., Zhang, X., & Zhao, T. (2022). GWL_FCS30: global 30 m wetland map with fine classification system using multi-sourced and time-series remote sensing imagery in 2020 [Data set, Version 1]. Link to source: https://doi.org/10.5281/zenodo.7340516

% mangroves
> 0100

Global mangrove ecosystem distribution

Mangrove ecosystems cover approximately 15.7 million ha globally; just five countries (Australia, Brazil, Indonesia, Mexico, and Nigeria) contain nearly 50% of the world’s mangrove ecosystem area (FAO, 2020). Green shaded areas indicate the general location of mangrove ecosystems; zoom in for details.

Liu, L., Zhang, X., & Zhao, T. (2022). GWL_FCS30: global 30 m wetland map with fine classification system using multi-sourced and time-series remote sensing imagery in 2020 [Data set, Version 1]. Link to source: https://doi.org/10.5281/zenodo.7340516

The Details

Current State

We estimated that coastal wetland protection avoids emissions of 2.33–5.74 t CO₂‑eq /ha/yr, while also sequestering an additional 1.22–2.14 t CO₂‑eq /ha/yr depending on the ecosystem (Tables 1a–c; see the Appendix for more information). We estimated effectiveness as the avoided CO₂ emissions and the retained carbon sequestration capacity attributable to the reduction in wetland loss conferred by protection, as detailed in Equation 1. First, we calculated the difference between the rate of wetland loss outside PAs and MPAs (Wetland lossbaseline) versus inside PAs and MPAs, since protection does not entirely prevent degradation. Loss rates were primarily driven by anthropogenic habitat conversion. The effectiveness of protection was 53–59% (Reduction in loss). We then multiplied the avoided wetland loss by the sum of the avoided CO₂ emissions associated with the loss of carbon stored in sediment and biomass in one ha of wetland each year over a 30-yr timeframe (Carbonavoided emissions) and the amount of carbon sequestered via long-term storage in sediment carbon by one ha of protected wetland each year over a 30-yr timeframe (Carbonsequestration).

Equation 1.

\[ Effectiveness = (Wetland\text{ }loss_{baseline}\times Reduction\text{ }in\text{ }loss)\times(Carbon_{avoided\text{ } emissions} + Carbon_{sequestration}) \]

We did this calculation separately for mangrove, salt marsh, and seagrass ecosystems, because many of these factors, such as carbon emission and sequestration rates, protection effectiveness, and loss rates, vary across ecosystem types. The rationale for increasing protection varies between coastal wetland ecosystem types, but in all cases, protection is an important tool for retaining and building long-lived carbon stocks. Additionally, climate impacts associated with this solution could be much greater than estimated if protection efficacy improves or is higher than our estimates of 53–59%. 

Table 1a. Effectiveness at avoiding emissions and sequestering carbon in mangrove ecosystems.

Unit: t CO₂‑eq /ha protected/yr, 100-yr basis

25th percentile 5.64
mean 6.80
median (50th percentile) 5.74
75th percentile 7.42

Unit: t CO₂‑eq /ha protected/yr, 100-yr basis

25th percentile 2.00
mean 2.14
median (50th percentile) 2.14
75th percentile 2.38

Unit: t CO₂‑eq /ha protected/yr, 100-yr basis

25th percentile 7.64
mean 8.94
median (50th percentile) 7.88
75th percentile 9.81

Table 1b. Effectiveness at avoiding emissions and sequestering carbon in salt marsh ecosystems.

Unit: t CO₂‑eq /ha protected/yr, 100-yr basis 

25th percentile 2.79
mean 2.90
median (50th percentile) 2.90
75th percentile 3.01

Unit: t CO₂‑eq /ha protected/yr, 100-yr basis

25th percentile 1.59
mean 1.90
median (50th percentile) 1.88
75th percentile 2.19

Unit: t CO₂‑eq /ha protected/yr, 100-yr basis

25th percentile 4.38
mean 4.80
median (50th percentile) 4.78
75th percentile 5.20

Table 1c. Effectiveness at avoiding emissions and sequestering carbon in seagrass ecosystems.

Unit: t CO₂‑eq /ha protected/yr, 100-yr basis

25th percentile 2.11
mean 2.33
median (50th percentile) 2.33
75th percentile 2.56

Unit: t CO₂‑eq /ha protected/yr, 100-yr basis

25th percentile 1.04
mean 1.53
median (50th percentile) 1.22
75th percentile 1.71

Unit: t CO₂‑eq /ha protected/yr, 100-yr basis

25th percentile 3.15
mean 3.86
median (50th percentile) 3.56
75th percentile 4.27

We estimate that coastal wetland protection costs approximately US$1–2/t CO₂‑eq for mangrove and salt marsh ecosystems and seagrass ecosystem protection saves US$6/t CO₂‑eq (Tables 2a–c). This is based on protection costs of roughly US$11/ha and revenue of US$23/ha compared with the baseline for mangrove/salt marsh and seagrass ecosystems, respectively. However, data related to the costs of coastal wetland protection are extremely limited, and these estimates are uncertain. These estimates likely underestimate the potentially high costs of coastal land acquisition, for instance.

The costs of coastal wetland protection include up-front costs of land acquisition (for salt marshes and mangroves) and other one-time expenditures as well as ongoing operational costs. Protecting coastal wetlands also generates revenue, primarily through increased tourism. For consistency across solutions, we did not include revenue associated with benefits other than climate change mitigation.

Due to data limitations, we estimated the cost of land acquisition for ecosystem protection for mangroves and salt marshes by extracting coastal forest land purchase costs reported by Dinerstein et al. (2024), who found a median cost of US$1,115/ha (range: US$78–5,910/ha), which we amortized over 30 years. For seagrass ecosystems, which do not generally require land acquisition, we based initial costs were on McCrea-Strub et al.’s (2011) findings that reported a median MPA start-up cost of US$208/ha (range: US$55–434/ha) to cover expenses associated with infrastructure, planning, and site research, which we amortized over 30 years.

Costs of PA maintenance were estimated as US$17/ha/yr (Waldron et al., 2020). While these estimates reflect the costs of effective enforcement and management, many PAs lack sufficient funding for effective management (Bruner et al., 2004). Costs of MPA maintenance were estimated at US$14/ha/yr, though only 16% of the MPAs surveyed in this study reported their current funding as sufficient (Balmford et al., 2004). Tourism revenues directly attributable to protection were estimated to be US$43/ha/yr (Waldron et al., 2020) based on estimates for all PAs and MPAs and excluding downstream revenues. For consistency across solutions, we did not include revenues associated with ecosystem services, which would increase projected revenue.

We also excluded carbon credits as a revenue source due to the challenges inherent in accurate carbon accounting in these ecosystems and their frequently intended use to offset carbon emissions, similar to reported concerns with low-quality carbon credits in forest conservation projects (West et al., 2023). Future actions could explore policies that increase market financing for coastal wetland protection in more holistic ways, such as contributions-based approaches as suggested for forests (Blanchard et al., 2024). Financial support will be critical for backing conservation implementation (Macreadie et al., 2022), particularly in the face of existing political and economic challenges that have historically limited expansion. 

Table 2. Cost per unit climate impact.

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

estimate 1

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

estimate 2

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

estimate -6

Negative value indicates cost savings.

We define a learning curve as falling costs with increased adoption. The costs of coastal wetland protection do not fall with increasing adoption, so there is no learning curve for this solution.

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.

Protect Coastal Wetlands is an EMERGENCY BRAKE climate solution. It has the potential to deliver a more rapid impact than gradual 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.

Adoption

We estimated that approximately 8.04 million ha of coastal wetlands are currently protected, with 5.13 million ha recognized as PAs and MPAs in strict (I–II) protection categories and 2.90 million ha in non-strict protection categories (III–IV) (Tables 3a–c; Garnett et al., 2018; UNEP-WCMC & IUCN, 2024, see Appendix). Indigenous People’s Lands (IPLs) cover an additional 3.44 million ha; we did not include these in our analysis due to limited data, but we recognize that these sites might currently deliver conservation benefits. In total, we estimate that roughly 15% of all coastal wetlands have some protection (as MPAs or PAs in IUCN categories I–IV), though only about 9% are under strict protection (IUCN categories I or II). Across individual ecosystem types, strict protection categories (IUCN I–II) are highest for mangroves (~15%) and lowest for seagrasses (~7%).

Our estimates of PA and MPA protection (12–19%) were lower than previously reported estimates for mangroves (40–43%, Dabalà et al., 2023; Leal and Spalding, 2024), tidal marshes (45%, Worthington et al., 2024), and seagrasses (26%, United Nations Environment Programme [UNEP], 2020). This is likely because our calculations excluded IUCN categories (“not assigned,” “not applicable,” and “not reported”) that contain large areal estimates for each ecosystem type – 4.3 million ha (mangrove), 1.9 million ha (salt marsh), and 5.4 million ha (seagrasses) – because their protection category was unclear as well as IUCN protection categories V–VI, which permit sustainable use and where extractive activities that could degrade these ecosystems are less formally restricted. Our spatial analysis also differed (see Appendix).

Table 3a. Current extent of mangrove ecosystems under legal protection by ecosystem type (circa 2023). “Strict Protection” includes land within IUCN Categories I–II PAs or MPAs. “Nonstrict Protection” includes land within IUCN Categories III–IV PAs or MPAs. “Other” includes land within all remaining IUCN PA or MPA categories (Million ha protected).

Table 3. Current extent of ecosystems under legal protection by ecosystem type (circa 2023). “Strict Protection” includes land within IUCN Categories I–II PAs or MPAs. “Nonstrict Protection” includes land within IUCN Categories III–IV PAs or MPAs. “Other” includes land within all remaining IUCN PA or MPA categories.

Unit: million ha protected

Strict Protection 2.35
Nonstrict Protection 0.59
Total (Strict + Nonstrict) 2.94
IPL 1.86
Other 7.52

Unit: million ha protected

Strict Protection 0.62
Nonstrict Protection 0.62
Total (Strict + Nonstrict) 1.24
IPL 1.09
Other 3.14

Unit: million ha protected

Strict Protection 2.17
Nonstrict Protection 1.69
Total (Strict + Nonstrict) 3.86
IPL 0.49
Other 9.00

We calculated the rate of PA and MPA expansion based on their recorded year of establishment. Protection expanded by an average of 59,600, 19,700, and 98,500 ha/yr in mangrove, salt marsh, and seagrass ecosystems, respectively (Tables 4a–c; Figure 3a). Salt marsh ecosystems have the lowest absolute rate of coastal wetland protection expansion (Figure 3b), while seagrasses have the lowest expansion of PAs relative to their adoption ceiling (Figure 3, right). The median total annual adoption trend across the three ecosystems is roughly 123,100 ha/yr (roughly 0.12 million ha/yr).

Table 4. 2000–2020 adoption trend for legal protection of ecosystems.

Unit: ha/yr protected

25th percentile 23,500
mean 59,600
median (50th percentile) 40,700
75th percentile 76,600

Unit: ha/yr protected

25th percentile 8,400
mean 19,700
median (50th percentile) 18,500
75th percentile 23,300

Unit: ha/yr protected

25th percentile 12,800
mean 98,500
median (50th percentile) 37,800
75th percentile 142,900

Figure 3. (a) Areal trend in coastal wetland protection by ecosystem type (2000–2020). These values reflect only the area located within IUCN Class I–IV PAs or MPAs; (ha/yr protected). (b) Trend in coastal wetland protection by ecosystem type as a percent of the adoption ceiling. These values reflect only the area located within IUCN Class I–IV PAs or MPAs; (Percent). Source: Project Drawdown original analysis.

Credit: Project Drawdown

We estimate an adoption ceiling of 54.6 million ha of coastal wetlands globally, which includes 15.7 million ha of mangroves, 7.50 million ha of salt marshes, and 31.4 million ha of seagrasses (Tables 5a–c). This estimate is in line with recent existing global estimates of coastal wetlands (36–185 million ha), which have large ranges due to uncertainties surrounding seagrass and salt marsh distributions (Macreadie et al., 2021, Krause et al., 2025). The adoption ceiling of our solution is therefore a conservative estimate of potential climate impact if global areas are indeed larger than calculated. While the protection of all existing coastal wetlands is highly unlikely, these values are used to represent the technical limits of adoption of this solution.

Table 5. Adoption ceiling: upper limit for adoption of legal protection of ecosystems.

Unit: million ha protected

estimate 15.7

Unit: million ha protected

estimate 7.50

Unit: million ha protected

estimate 31.4

We defined the lower end of the achievable range for coastal wetland protection (under IUCN categories I–IV) as 50% of the adoption ceiling and the higher end of the achievable range as 70% of the adoption ceiling for each ecosystem (Tables 6a–c). These numbers are ambitious but precedent exists to support them. For instance, roughly 11 countries already protect over 70% of their mangroves (Dabalà et al., 2023), and the global “30 by 30” target aims to protect 30% of ecosystems on land and in the ocean by 2030 (Roberts et al., 2020). Further, a significant extent of existing global coastal wetland areas already fall under non-strict protection categories not included in our analysis (V–VI and “Other”). These are prime candidates for conversion to stricter protection categories, so long as the designation confers real conservation benefits; recent work suggests that stricter protection can coincide with increased degradation in some mangroves (Heck et al., 2024).

Current adoption of PAs and MPAs in many countries with the highest land areas of coastal wetlands is low. For example, protection levels (IUCN I–IV) in countries with the top 10 greatest mangrove areas ranges between less than 1% (India, Myanmar, Nigeria, and Papua New Guinea) to 8.8–21.2% (Australia, Bangladesh, Brazil, Indonesia, Malaysia, and Mexico;Dabalà et al., 2023). Expansion of PAs, particularly under IUCN I–IV categories, is a significant challenge with real implementation barriers due to competing land uses and local reliance on these areas for livelihoods. Further, protection does not guarantee conservation benefits, and significant funding is required to maintain/enforce these areas or they run the risk of becoming “paper parks” (Di Minin & Toivonen, 2015). Strong policy and financial incentives for conservation will be necessary to achieve these ambitious goals. Pathways for operationalizing protection could include finance, governance, and stakeholder alignment and will likely require a combination of these tactics around the world. 

Table 6. Range of achievable adoption levels for ecosystems.

Unit: million ha protected

Current Adoption 2.94
Achievable – Low 7.85
Achievable – High 11.0
Adoption Ceiling 15.7

Unit: million ha protected

Current Adoption 1.24
Achievable – Low 3.75
Achievable – High 5.25
Adoption Ceiling 7.50

Unit: million ha protected

Current Adoption 3.86
Achievable – Low 15.7
Achievable – High 22.0
Adoption Ceiling 31.4

Impacts

We estimated that coastal wetland protection currently avoids approximately 0.04 Gt CO₂‑eq/yr, with potential impacts of 0.27 Gt CO₂‑eq/yr at the adoption ceiling (Table 7a–c, see Appendix for more information on the calculations). The lower-end achievable scenario (50% protection) would avoid 0.14 Gt CO₂‑eq/yr, and the upper-end achievable scenario (70% protection) would avoid 0.20 Gt CO₂‑eq/yr (Tables 7a–c). These values are in line with Macreadie et al. (2021), who estimated a maximum mitigation potential from avoided emissions due to degradation (land conversion) of 0.30 (range: 0.14–0.47) Gt CO₂‑eq/yr for mangrove, salt marsh, and seagrass ecosystems. Our estimate was slightly lower, but within their range, and differed in a few key ways. We accounted for the effectiveness of protection at reducing degradation (53–59%, instead of assuming 100%), included retained carbon sequestration with each hectare protected, and used slightly different loss rates and ecosystem areas.

Table 7. Climate impact at different levels of adoption for ecosystems.

Unit: Gt CO₂‑eq/yr, 100-yr basis

Current Adoption 0.02
Achievable – Low 0.06
Achievable – High 0.09
Adoption Ceiling 0.12

Unit: Gt CO₂‑eq/yr, 100-yr basis

Current Adoption 0.01
Achievable – Low 0.02
Achievable – High 0.03
Adoption Ceiling 0.04

Unit: Gt CO₂‑eq/yr, 100-yr basis

Current Adoption 0.01
Achievable – Low 0.06
Achievable – High 0.08
Adoption Ceiling 0.11

Extreme Weather Events

Wetlands buffer coastal communities from waves and storm surge due to extreme weather and have important roles in disaster risk mitigation (Sheng et al., 2022; Guannel et al., 2016). Mangroves slow the flow of water and reduce surface waves to protect more than 60 million people in low-lying coastal areas, mainly in low- and middle-income countries (McIvor et al., 2012; Hochard et al., 2021). Wetlands also protect structures against damage during storms and lead to savings in insurance claims (Barbier et al., 2013; Sheng et al., 2022). Mangroves provide an estimated US$65 billion in flood protection globally (Menéndez et al., 2020). A study of the damages of Hurricane Sandy found that wetlands in the northeastern United States avoided US$625 million in direct flood damages (Narayan et al., 2017).

Income and Work

Wetlands are a contributor to local livelihoods, providing employment for coastal populations via the fisheries and tourism that they support. Coastal ecosystems, such as mangroves, are crucial for subsistence fisheries as they sustain approximately 4.1 million small-scale fishers (Leal and Spalding, 2022). Wetlands provide sources of income for low-income coastal communities as they make small-scale fishing accessible, requiring limited gear and materials to fish (Cullen-Unsworth & Unsworth, 2018). The economic value of mangrove ecosystem services is estimated at US$33,000–57,000/ha/yr and is a major contributor to the national economies of low- and middle-income countries with mangroves (UNEP, 2014).

Food Security

Mangroves support the development of numerous commercially important fish species and strengthen overall fishery productivity. For example, research conducted across 6,000 villages in Indonesia found that rural coastal households near high and medium-density mangroves consumed more fish and aquatic animals than households without mangroves nearby (Ickowitz et al., 2023). Seagrasses also support fisheries as 20% of the world’s largest fisheries rely on seagrasses for habitats (Jensen, 2022). The amount and diversity of species within seagrasses also provide important nutrition for fishery species (Cullen-Unsworth & Unsworth, 2018).

Equality

Coastal wetlands are significant in cultural heritages and identities for nearby people. They can be associated with historical, religious, and spiritual values for communities and especially for Indigenous communities (UNEP, 2014). For example, a combination of sea-level rise and oil and gas drilling have contributed to the decline of coastal wetlands in Louisiana, which threatens livelihoods and deep spiritual ties of local Indigenous tribes (Baniewicz, 2020; Hutchinson, 2022). Indigenous people have a long history of managing and protecting coastal wetlands (Mathews & Turner, 2017). Efforts to protect these areas must include legal recognition of Indigenous ownership to support a just and sustainable conservation process (Fletcher et al., 2021).

Nature Protection

Coastal wetlands are integral in supporting the biodiversity of surrounding watersheds. High species diversity of mangroves and seagrasses provide a unique habitat for marine life, birds, insects, and mammals, and contain numerous threatened or endangered species (Green and Short, 2003; U.S. EPA, 2025a). A variety of species rely on wetlands for food and shelter, and they can provide temporary habitats for species during critical times in their life cycles, such as migration and breeding (Unsworth et al., 2022). Wetlands can improve water quality, making the surrounding ecosystem more favorable to supporting marine life (Cullen-Unsworth & Unsworth, 2018). Seagrasses can improve coral health by filtering water and reducing pathogens that could cause disease (Cullen-Unsworth & Unsworth, 2018).

Land Resources

Wetlands reduce coastal erosion which can benefit local communities during strong storms (Jensen, 2022). Wetlands mitigate erosion impacts by absorbing wave energy that would degrade sand and other marine sediments (U.S. EPA, 2025b). Specifically, mangroves reduce erosion through their aerial root structure that retain sediments that would otherwise degrade the shoreline (Thampanya et al., 2006).

Water Quality

Coastal wetlands improve the water quality of watersheds by filtering chemicals, particles (including microplastics), sediment, and cycling nutrients (Unsworth et al. 2022). There is even evidence that wetlands can remove viruses and bacteria from water, leading to better sanitation and health for marine wildlife and humans (Lamb et al., 2017).

Other

Additionality in this solution refers to whether the ecosystem would have been degraded without protection. In this analysis, we assumed protection confers additional carbon benefits as it reduces degradation and associated emissions. Another aspect of additionality, though not directly relevant to our analysis, is whether coastal wetlands would have been protected in the absence of carbon financing. This could become increasingly important if protection efforts seek carbon credits, since many wetlands are protected for other benefits, such as flood resilience and biodiversity.

The permanence of stored carbon in coastal wetlands is another critical issue as climate change impacts unfold. For instance, with sea-level rise, the ability of salt marshes to expand both vertically and laterally can determine resiliency, suggesting that protection of wetlands might also need to include adjacent areas for expansion (Schuerch et al., 2018). On a global scale, recent research suggests that global carbon accumulation might actually increase by 2100 from climate change impacts on tidal wetlands (Wang et al., 2021), though more work is needed as other work suggests the opposite (Noyce et al., 2023). There is also substantial risk of reversal of carbon benefits if protections are reversed or unenforced, which can require long-term financial investments, community engagement, and management/enforcement commitments (Giakoumi et al., 2018), particularly if the land is leased.

Finally, there are significant uncertainties associated with the available data on coastal wetland areas and distributions, loss rates, drivers of loss, extent and boundaries of PAs/MPAs, and efficacy of PAs/MPAs at reducing coastal wetland disturbance. For example, the geospatial datasets we used to identify the adoption ceiling for this solution could include partially degraded systems, such as drained wetlands, where protection alone would not stop emissions or restore function without restoration – yet we lack enough data to distinguish these current differences at a global scale. Similarly, legal protection of coastal wetlands does not always prevent degradation (Heck et al., 2024). The emissions dynamics of both intact and degraded coastal wetlands are also uncertain. Even less is known about the impacts of different types of degradation on coastal wetland carbon dynamics and how they vary spatially and temporally around the world.

There are several risks associated with coastal wetland protection. Leakage, wherein protection in one region could prompt degradation of another, could reduce climate benefits (Renwick et al., 2015). Strict conservation of coastal wetlands could impact local economies, creating “poverty traps” if protection threatens livelihoods (McNally et al., 2011). Conservation projects also risk unequal distribution of benefits (Lang et al., 2023). In places where habitats are fragmented or existing infrastructure limits landward migration, even protected coastal wetlands are at risk of being lost with climate change (commonly known as “the coastal squeeze”; Borchert et al., 2018). Funding gaps risk reversal of climate benefits despite initial conservation efforts; most MPAs and PAs report a lack of funding (Balmford et al., 2004; Bruner et al., 2004). If coastal wetlands are subjected to human impacts that protection cannot prevent, such as upgradient nutrient pollution, there could also be a risk of increased GHG emissions (Feng et al., 2025) and ecosystem degradation.

Trade-offs associated with protection of coastal wetlands include emission of other GHGs not quantified in this solution that have higher global warming potentials (GWP) than CO₂. Methane and nitrous oxide emissions can be measurable in coastal wetland ecosystems, though it is important to recognize that degradation can significantly impact the magnitude and types of effluxes, too. In mangroves, methane evasion can offset carbon burial by almost 20% based on a 20-yr GWP (Rosentreter et al., 2018). In seagrasses, methane and nitrous oxide effluxes can offset burial on average, globally, by 33.4% based on a 20-yr GWP and 7.0% based on a 100-yr GWP (Eyre et al., 2023). Finally, conservation of coastal land can also restrict development of desirable coastal property for other uses.

Reinforcing

Other ecosystems often occur adjacent to areas of coastal wetlands, and the health of nearby ecosystems can be improved by the services provided by intact coastal wetlands (and vice versa). 

Reducing food loss and waste and improving diets reduce demand for agricultural land. These solutions reduce pressure to convert coastal wetlands to agricultural use, easing expansion of PAs.

Competing

Mangrove deforestation can occur for fuel wood needs. Fuel wood sourced from mangroves could be replaced with wood sourced from other forested ecosystems.

Consensus of effectiveness in reducing emissions and maintaining carbon removal: High

There is high scientific consensus that coastal wetland protection is an important strategy for reducing wetland loss due to degradation and that degradation results in carbon stock loss from coastal wetlands. Rates of wetland loss are generally lower inside PAs than outside them. An analysis of over 4,000 PAs (wetland and non-wetland area) showed 59% of sites are in “sound management,” which generally reflects PAs with strong enforcement, management implementation, and conservation outcome indicators (Leverington et al., 2010). Here we used a conservative effectiveness of 59% for salt marshes and mangroves that are under legal protection, consistent with the value from Leverington et al. (2010). Other regional studies show similar PA effectiveness values, with 25–50% of wetland PAs in China exhibiting moderate to very high conservation effectiveness (Lu et al., 2016).

Seagrasses differ from mangroves and salt marshes in that they fall under MPA designation because they are subtidal, or submerged. In an analysis of effectiveness of 66 MPAs in 18 countries, nearly 53% of MPAs reported positive or slightly positive ecosystem outcomes (Rodríguez-Rodríguez & Martínez-Vega, 2022). Less is known about MPA effectiveness for seagrass meadows specifically; we assumed an effectiveness of 53% – similar to other MPAs.

Prevention of degradation via legal coastal wetlands protection avoids emissions by preserving carbon stocks while also retaining carbon sequestration capacity. Degradation of coastal wetlands results in measurable loss of short- and long-lived carbon stocks, with emissions that vary based on ecosystem and degradation type (Donato et al., 2011, Holmquist et al., 2023, Lovelock et al., 2017, Mcleod et al., 2011, Pendleton et al., 2012). Estimates of existing carbon stocks in coastal wetlands are substantial, ranging between 8.97–32.7 Gt of carbon (32.9–120 Gt CO₂‑eq ), most of which is likely susceptible to degradation (Macreadie et al., 2021).

The results presented in this document synthesize findings from 14 global datasets. We recognize that geographic bias in the information underlying global data products creates bias and hope this work inspires research and data sharing on this topic in underrepresented regions and understudied ecosystems.

Take Action

Looking to get involved? Below are some key actions for this solution that can get you started, arranged according to different roles you may play in your professional or personal life.

These actions are meant to be starting points for involvement and are not intended to be prescriptive or necessarily suggest they are the most important or impactful actions to take. We encourage you to explore and get creative!

Lawmakers and Policymakers

  • Grant Indigenous communities full property rights and autonomy; support them in monitoring, managing, and enforcing MPAs/PAs/IPLs.
  • Ensure effective enforcement and monitoring of existing PAs using real-time and satellite data, if available.
  • Create or strengthen legislative protections for coastal wetlands, requiring their consideration during land use planning and allowing for local decision-making.
  • Start expanding PAs by first designating coastal wetlands adjacent to existing MPAs/PAs/IPLs.
  • Increase designated PAs and MPAs and consider all benefits (e.g., climate, human well-being, biodiversity) and dynamics (e.g., water flows, soil, agriculture) when designating PAs to ensure maximum benefits.
  • Ensure PAs and MPAs don’t displace, violate rights, or reduce access to vital resources for local and Indigenous communities.
  • Classify and map coastal wetlands and tidal information; create local, national, and international standards for classification.
  • Integrate river, watershed, and dam management into coastal wetland protection.
  • Streamline regulations and legal requirements, when possible to simplify management and designation of MPAs/PAs/IPLs.
  • Use financial incentives such as subsidies, tax breaks, payments for ecosystem services (PES), and debt-for-nature swaps to protect coastal wetlands from development.
  • Conduct proactive land-use planning to avoid roads and other development projects that might interfere with MPAs and PAs.
  • Coordinate MPA and PA efforts horizontally (e.g., across agencies) and vertically (e.g., across subnational, national, and international efforts), ensuring an inclusive process for local and Indigenous communities.
  • Incorporate MPAs/PAs/IPLs into local, national, and international climate plans (i.e., Nationally Determined Contributions).
  • Work with insurance companies to reduce insurance premiums for properties that protect or maintain coastal wetlands.
  • Create processes for legal grievances, dispute resolution, and restitution.
  • Create sustainable use regulations for protected coastal wetland areas that provide resources to local communities.
  • Empower local communities to manage coastal wetlands and ensure a participatory approach to designating and managing MPAs and PAs.
  • Create education programs that educate the public on MPA regulations, the benefits of coastal wetlands, and how to use resources sustainably.
  • Join, support, or create certification schemes for sustainable management of coastal wetlands.

Further information:

Practitioners

  • Avoid draining or degrading coastal wetlands.
  • Avoid developing intact coastal wetlands, including small-scale shoreline developments such as docks.
  • Invest in coastal wetland conservation, restoration, sustainable management practices, specialized research facilities, and other R&D efforts.
  • Participate in stakeholder engagements and help policymakers designate coastal wetlands, create regulations, and implement robust monitoring and enforcement.
  • Grant Indigenous communities full property rights and autonomy and support them in monitoring, managing, and enforcing PAs.
  • Ensure protected coastal wetlands don’t displace, violate rights, or reduce access to vital resources for local and Indigenous communities.
  • Integrate river, watershed, and dam management into coastal wetland protection.
  • Use real-time monitoring and satellite data to manage and enforce PA and MPA regulations.
  • Create sustainable use regulations for protected coastal wetland areas that provide resources to the local community.
  • Conduct proactive land-use planning to avoid infrastructure or development projects that might interfere with protected coastal wetlands or incentivize drainage.
  • Advocate for creating legal grievance processes, dispute resolution mechanisms, and restitution procedures for violations or disagreements over PAs and MPAs.
  • Advocate for or use financial incentives such as subsidies, tax breaks, and PES to protect coastal wetlands from development.
  • Utilize financial mechanisms such as biodiversity offsets, PES, high-integrity voluntary carbon markets, and debt-for-nature swaps to fund coastal wetland protection.
  • Help classify and map coastal wetlands and tidal information as well as create local, national, and international standards for classification.
  • Coordinate PA and MPA efforts horizontally (e.g., across agencies) and vertically (e.g., across subnational, national, and international efforts), ensuring an inclusive process for local and Indigenous communities.
  • Work with insurance companies to reduce insurance premiums for properties that protect or maintain coastal wetlands.
  • Join, support, or create certification schemes for sustainable management of coastal wetlands.
  • Create education programs that educate the public on MPA/PA/IPL regulations, the benefits of coastal wetlands, and how to use resources sustainably.

Further information:

Business Leaders

  • Ensure operations, development, and supply chains are not degrading coastal wetlands or interfering with PA or MPA management.
  • Integrate coastal wetland protection into net-zero strategies, if relevant.
  • Help revise existing or create new high-integrity carbon markets, institutions, rules, and norms to cultivate the demand for high-quality carbon credits.
  • Only purchase carbon credits from high-integrity, verifiable carbon markets, and do not use them as replacements for less carbon-intensive operations or claim them as offsets.
  • Consider donating to established coastal wetland protection funds in place of carbon credits.
  • Take advantage of financial incentives such as subsidies, tax breaks, and PES to coastal wetlands from development.
  • Amplify the voices of local communities and civil society to promote robust media coverage.
  • Invest in and support Indigenous and local communities' capacity for management, legal protection, and public relations.
  • Leverage political influence to advocate for stronger coastal wetland protection policies at national and international levels.
  • Conduct proactive land-use planning to avoid roads and other development projects that might interfere with PAs and MPAs or incentivize deforestation.
  • Join, support, or create certification schemes for sustainable management of coastal wetlands.

Further information:

Nonprofit Leaders

  • Advocate for enhanced enforcement of existing MPAs/PAs/IPLs, expansion of new MPAs/PAs/IPLs, and more public investments.
  • Help manage and monitor protected coastal wetlands using real-time monitoring and satellite data.
  • Provide financial support for MPAs/PAs/IPLs, monitoring, and enforcement.
  • Help conduct proactive land-use planning to avoid infrastructure or development projects that might interfere with protected coastal wetlands or incentivize drainage.
  • Advocate for creating legal grievance processes, dispute resolution mechanisms, and restitution procedures for violations or disagreements over PAs or MPAs.
  • Help revise existing or create new high-integrity carbon markets, institutions, rules, and norms to cultivate the demand for high-quality carbon credits.
  • Amplify the voices of local communities and civil society to promote robust media coverage.
  • Invest in and support the capacity of Indigenous and local communities for management, legal protection, and public relations.
  • Use or advocate for financial incentives such as subsidies, tax breaks, and PES to protect coastal wetlands from development.
  • Help classify and map coastal wetlands and tidal information as well as create local, national, and international standards for classification.
  • Work with insurance companies to reduce insurance premiums for properties that protect or maintain coastal wetlands.
  • Join, support, or create certification schemes for sustainable management of coastal wetlands.
  • Create education programs that educate the public on MPA/PA/IPL regulations, the benefits of coastal wetlands, and how to use resources sustainably.

Further information:

Investors

  • Ensure investment portfolios do not degrade coastal wetlands or interfere with MPAs/PAs/IPLs, using data, information, and the latest technology to inform investments.
  • Invest in coastal wetland protection, monitoring, management, and enforcement mechanisms.
  • Use financial mechanisms such as credible biodiversity offsets, PES, voluntary high-integrity carbon markets, and debt-for-nature swaps to fund coastal wetland protection.
  • Invest in and support Indigenous and local communities' capacity for legal protection and public relations.
  • Share data, information, and investment frameworks that successfully avoid investments that drive coastal wetland destruction with other investors and nongovernmental organizations.
  • Provide favorable loans to Indigenous communities and entrepreneurs and businesses protecting wetlands.
  • Join, support, or create certification schemes for sustainable management of coastal wetlands.

Further information:

Philanthropists and International Aid Agencies

  • Advocate for enhanced enforcement of existing MPAs/PAs/IPLs, expansion of new MPAs/PAs/IPLs, and public investments.
  • Help manage and monitor protected coastal wetlands, using real-time monitoring and satellite data.
  • Provide technical and financial assistance to low- and middle-income countries and communities to protect coastal wetlands.
  • Provide financial support to organizations and institutions developing and deploying monitoring technology and conducting wetland research.
  • Help manage and monitor protected coastal wetlands using real-time monitoring and satellite data.
  • Help conduct proactive land-use planning to avoid infrastructure or development projects that might interfere with protected coastal wetlands or incentivize drainage.
  • Help revise existing or create new high-integrity carbon markets, institutions, rules, and norms to cultivate the demand for high-quality carbon credits.
  • Amplify the voices of local communities and civil society to promote robust media coverage.
  • Invest in and support Indigenous and local communities' capacity for management, legal protection, and public relations.
  • Advocate for creating legal grievance processes, dispute resolution mechanisms, and restitution procedures for violations or disagreements over PAs or MPAs.
  • Help classify and map coastal wetlands and tidal information as well as create local, national, and international standards for classification.
  • Work with insurance companies to reduce insurance premiums for properties that protect or maintain coastal wetlands.
  • Join, support, or create certification schemes for sustainable management of coastal wetlands.
  • Create education programs that educate the public on MPA/PA/IPL regulations, the benefits of coastal wetlands, and how to use resources sustainably.

Further information:

Thought Leaders

  • Advocate for enhanced enforcement of existing MPAs/PAs/IPLs, expansion of new MPAs/PAs/IPLs, and for public investments.
  • Advocate for or use financial incentives such as subsidies, tax breaks, PES, and debt-for-nature swaps to protect coastal wetlands from development.
  • Help manage and monitor protected coastal wetlands using real-time monitoring and satellite data.
  • Help conduct proactive land-use planning to avoid infrastructure or development projects that might interfere with protected coastal wetlands or incentivize drainage.
  • Advocate for creating legal grievance processes, dispute resolution mechanisms, and restitution procedures for violations or disagreements over PAs or MPAs.
  • Help revise existing or create new high-integrity carbon and biodiversity markets, institutions, rules, and norms to cultivate the demand for high-quality carbon credits.
  • Amplify the voices of local communities and civil society to promote robust media coverage.
  • Support Indigenous and local communities' capacity for legal protection, management, and public relations.
  • Help classify and map coastal wetlands and tidal information as well as create local, national, and international standards for classification.
  • Join, support, or create certification schemes for sustainable management of coastal wetlands.
  • Create programs that educate the public on MPA/PA/IPL regulations, the benefits of coastal wetlands, and how to use resources sustainably.

Further information:

Technologists and Researchers

  • Study ecosystem services provided by coastal wetlands and catalogue the benefits.
  • Improve mapping of coastal wetland areas, carbon content and dynamics, tidal impacts, degradation types and levels, and emissions data – specifically methane and nitrous oxide.
  • Improve monitoring methods using field measurements, models, satellite imagery, and GIS tools.
  • Research adjacent technologies and practices such as seaweed farm management, kelp forest conservation, sediment management, and biodiversity restoration.
  • Conduct meta-analyses or synthesize existing literature on coastal wetlands and protection efforts.
  • Explore ways to use smart management systems for PAs and MPAs, including the use of real-time and satellite data.
  • Develop land-use planning tools that help avoid infrastructure or development projects that might interfere with PAs and MPAs or incentivize drainage.
  • Create tools for local communities to monitor coastal wetlands, such as mobile apps, e-learning platforms, and mapping tools.
  • Develop verifiable carbon credits using technology such as blockchain to improve the integrity of carbon markets.
  • Develop supply chain tracking software for investors and businesses seeking to create sustainable portfolios and products.

Further information:

Communities, Households, and Individuals

  • Avoid draining or degrading coastal wetlands.
  • Avoid developing intact coastal wetlands, including small-scale shoreline developments such as docks.
  • Help manage and monitor protected coastal wetlands using real-time monitoring and satellite data.
  • Establish coordinating bodies for farmers, developers, landowners, policymakers, dam operators, and other stakeholders to holistically manage PAs.
  • Advocate for enhanced enforcement of existing MPAs/PAs/IPLs, expansion of new MPAs/PAs/IPLs, and public investments.
  • Help conduct proactive land-use planning to avoid infrastructure or development projects that might interfere with protected coastal wetlands or incentivize drainage.
  • Advocate for creating legal grievance processes, dispute resolution mechanisms, and restitution procedures for violations or disagreements over PAs or MPAs.
  • Help revise existing or create new high-integrity carbon and biodiversity markets, institutions, rules, and norms to cultivate the demand for high-quality carbon credits.
  • Support Indigenous communities' capacity for management, legal protection, and public relations.
  • Use or advocate for financial incentives such as subsidies, tax breaks, and PES to protect coastal wetlands from development.
  • Help classify and map coastal wetlands and tidal information as well as create local, national, and international standards for classification.
  • Ensure PAs and MPAs don’t displace, violate rights, or reduce access to vital resources for local and Indigenous communities.
  • Work with insurance companies to reduce insurance premiums for properties that protect or maintain coastal wetlands.
  • Participate or volunteer in local coastal wetland protection efforts.
  • Plant native species to help improve the local ecological balance and stabilize the soil – especially on waterfront property.
  • Use nontoxic cleaning and gardening supplies, purchase unbleached paper products, and recycle to help keep pollution and debris out of wetlands.
  • Join, support, or create certification schemes for sustainable management of coastal wetlands.
  • Create education programs that educate the public on MPA/PA/IPL regulations, the benefits of coastal wetlands, and how to use resources sustainably.

Further information:

“Take Action” Sources

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Appendix

In this analysis, we integrated global land cover data; shapefiles of PAs, MPAs, and IPLs; and ecosystem type (mangroves, salt marshes, seagrasses) data on carbon emissions and sequestration rates to calculate currently protected coastal wetland area, total global coastal wetland area, and avoided emissions and additional sequestration from coastal wetland protection by ecosystem type (mangroves, salt marshes, and seagrasses).

Land Cover Data

We used two land cover data products to estimate coastal wetland extent by ecosystem type (mangroves, salt marshes, seagrasses) inside and outside of PAs, MPAs, and IPLs: 1) a global 30 m wetland map, GWL_FCS30, for mangroves and salt marshes (Zhang et al., 2023), and 2) the global distribution of seagrasses map from UN Environment World Conservation Monitoring Centre (UNEP-WCMC & Short, 2021).

Protected Coastal Wetland Areas

The IUCN defines PAs, including MPAs, as geographically distinct areas managed primarily for the long-term conservation of nature and ecosystem services. They are further disaggregated into six levels of protection, ranging from strict wilderness preserves to sustainable use areas that allow for some natural resource extraction (including logging). We calculated all levels of protection but only considered protection categories I–IV in our analysis of adoption. We recognized that other protection categories might provide conservation benefits. We excluded categories labeled as “Not Applicable (NAP),” “Not Reported (NR),” “Not Assigned (NAS),” as well as categories VI and VII. We also estimated IPL area based on available data, but emphasized that much of their extent has not been fully mapped nor recognized for its conservation benefits (Garnett et al., 2018). Additionally, the IPL dataset only covered land and therefore did not include seagrass ecosystems explicitly beyond the extent that ecosystems bordering terrestrial IPL areas were captured within the 1 km pixels of analysis. Coastal wetlands also lack data on the effectiveness of protection with IPLs, so we did not include IPL data as currently protected in our estimates.

We identified protected coastal wetland areas using the World Database on PAs (UNEP-WCMC & IUCN, 2024), which contains boundaries for each PA or MPA and additional information, including their establishment year and IUCN management category (Ia to VI, NAP, NR, and NAS). For each PA or MPA polygon, we extracted the coastal wetland area based on the datasets in the Land Cover Data section. Our spatial analysis required the center point of the pixel of each individual ecosystem under consideration to be covered by the PA or MPA polygon in order to be classified as protected, which is a relatively strict spatial extraction technique that likely leads to lower estimates of conservation compared to previous work with differing techniques (Dabalà et al., 2023).

We used the maps of IPLs from Garnett et al. (2018) to identify IPLs that were not inside of established PAs. We calculated the total coastal wetland area within IPLs (excluding PAs and MPAs) using the same coastal wetland data sources.

Coastal Wetland Loss, Additional Sequestration, and Emissions Factors

We aggregated coastal wetland loss rates by ecosystem type (mangroves, salt marshes, seagrasses). We used data on PA and MPA effectiveness to calculate the difference in coastal wetland loss rates attributable to protection (Equation A1). We compiled baseline estimates of current rates of coastal wetland degradation from all causes (%/yr) from existing literature as shown in the “Detailed coastal wetland loss data” tab of the Supporting Data spreadsheet and used in conjunction with estimates of reductions in loss, 53–59%, associated with protection.

Equation A1.

\[ Wetland\text{ }loss_{avoided}=(Wetland\text{ }loss_{baseline}\times Reduction\text{ }in\text{ }loss) \]

We then used the ratio of coastal wetland loss in unprotected areas versus PAs to calculate avoided CO₂ emissions and additional carbon sequestration for each adoption unit. Specifically, we estimated the carbon benefits of avoided coastal wetland loss by multiplying avoided coastal wetland loss by avoided CO₂ emissions (30-yr time horizon; Equation A2) and carbon sequestration rates (30-yr time horizon; Equation A3) for each ecosystem type. Importantly, the emissions factors we used account for carbon in above- and below-ground biomass and generally do not assume 100% loss of carbon stocks because many land use impacts may retain some stored carbon, some of which is likely resistant to degradation (see the “2. current state effectiveness tab” in the spreadsheet for more information). We derived our estimates of retained carbon sequestration from global databases on sediment organic carbon burial rates in each ecosystem (see the “2. current state effectiveness tab” in the spreadsheet for more information).

Equation A2.

\[ Avoided\text{ } emissions = Wetland\text{ }loss_{avoided} \times \sum_{t=1}^{30}{Emissions} \]

Equation A3.

\[ Sequestration = Wetland\text{ }loss_{avoided} \times \sum_{t=1}^{30}{Sequestration} \]

We then estimated effectiveness (Equation A4) as the avoided CO₂ emissions and the retained carbon sequestration capacity attributable to the reduction in wetland loss conferred by protection estimated in Equations S1–S3.

Equation A4.

\[ Effectiveness = Wetland\text{ }loss_{avoided} \times (Carbon_{avoided\text{ } emissions} + Carbon_{sequestration}) \]

Finally, we calculated climate impact (Equation A5) by multiplying the adoption area under consideration by the estimated effectiveness from Equation A4.

Equation A5.

\[ Climate\text{ }impact = Effectiveness \times Adoption \]

Appendix References

Garnett, S. T., Burgess, N. D., Fa, J. E., Fernández-Llamazares, Á., Molnár, Z., Robinson, C. J., Watson, J. E. M., Zander, K. K., Austin, B., Brondizio, E. S., Collier, N. F., Duncan, T., Ellis, E., Geyle, H., Jackson, M. V., Jonas, H., Malmer, P., McGowan, B., Sivongxay, A., & Leiper, I. (2018). A spatial overview of the global importance of Indigenous lands for conservation. Nature Sustainability, 1(7), 369–374. https://doi.org/10.1038/s41893-018-0100-6

UNEP-WCMC, & Short, F. T. (2021). Global distribution of seagrasses (version 7.1) [Data set]. UN Environment World Conservation Monitoring Centre. https://doi.org/10.34892/x6r3-d211

UNEP-WCMC, & IUCN. (2024). Protected planet: The world database on protected areas (WDPA) and world database on other effective area-based conservation measures (WD-OECM) [Data set]. Retrieved November 2024, from https://www.protectedplanet.net

Zhang, X., Liu, L., Zhao, T., Chen, X., Lin, S., Wang, J., Mi, J., & Liu, W. (2023). GWL_FCS30: a global 30 m wetland map with a fine classification system using multi-sourced and time-series remote sensing imagery in 2020. Earth System Science Data, 15(1), 265–293. https://doi.org/10.5194/essd-15-265-2023

Credits

Lead Fellow

  • Christina Richardson, Ph.D.

Contributors

  • Ruthie Burrows, Ph.D.

  • Avery Driscoll

  • James Gerber, Ph.D.

  • Daniel Jasper

  • Christina Swanson, Ph.D.

  • Alex Sweeney

  • Paul West, Ph.D.

Internal Reviewers

  • Aiyana Bodi

  • Avery Driscoll

  • James Gerber, Ph.D.

  • Hannah Henkin

  • Ted Otte

  • Christina Swanson, Ph.D.

Methods and Supporting Data

Methods and Supporting Data

Comments / Questions

  • Greenhouse gas quantity expressed relative to CO₂ with the same warming impact over 100 years, calculated by multiplying emissions by the 100-yr GWP for the emitted gases.

  • Greenhouse gas quantity expressed relative to CO₂ with the same warming impact over 20 years, calculated by multiplying emissions by the 20-yr GWP for the emitted gases.

  • 8th World Congress on Conservation Agriculture

  • Reducing greenhouse gas concentrations in the atmosphere by preventing or reducing emissions.

  • The process of increasing acidity.

  • The extent to which emissions reduction or carbon removal is above and beyond what would have occurred without implementing a particular action or solution.

  • An upper limit on solution adoption based on physical or technical constraints, not including economic or policy barriers. This level is unlikely to be reached and will not be exceeded.

  • The quantity and metric to measure implementation for a particular solution that is used as the reference unit for calculations within that solution.

  • A composting method in which organic waste is processed in freestanding piles that can be aerated actively with forced air or passively by internal convection.

  • The interactions of aerodynamic forces and flexible structures, often including the stucture's control system.

  • A process in which microbes break down organic materials in the presence of oxygen. This process converts food and green waste into nutrient-rich compost.

  • Farming practices that work to create socially and ecologically sustainable food production.

  • Addition of trees and shrubs to crop or animal farming systems.

  • Spread out the cost of an asset over its useful lifetime.

  • A crop that live one year or less from planting to harvest; also called annual.

  • aerated static piles

  • black carbon

  • Made from material of biological origin, such as plants, animals, or other organisms.

  • A renewable energy source generated from organic matter from plants and/or algae.

  • An energy source composed primarily of methane and CO₂ that is produced by microorganisms when organic matter decomposes in the absence of oxygen.

  • Carbon stored in biological matter, including soil, plants, fungi, and plant products (e.g., wood, paper, biofuels). This carbon is sequestered from the atmosphere but can be released through decomposition or burning.

  • Living or dead renewable matter from plants or animals, not including organic material transformed into fossil fuels. Peat, in early decay stages, is partially renewable biomass.

  • Biogas refined to the same quality as natural gas. CO₂ and impurities are removed, and the biomethane can be distributed and used in existing natural gas technologies.
     

  • A type of carbon sequestration that captures carbon from CO₂ via photosynthesis and stores it in soils, sediments, and biomass, distinct from sequestration through chemical or industrial pathways.

  • A climate pollutant, also called soot, produced from incomplete combustion of organic matter, either naturally (wildfires) or from human activities (biomass or fossil fuel burning).

  • A secure, decentralized way of digitally tracking transactions that could be used to improve the transparency and efficiency of carbon markets. 

  • High-latitude (>50°N or >50°S) climate regions characterized by short growing seasons and cold temperatures.

  • The components of a building that physically separate the indoors from the outdoor environment.

  • Businesses involved in the sale and/or distribution of solution-related equipment and technology, and businesses that want to support adoption of the solution.

  • A chemical reaction involving heating a solid to a high temperature; to make cement clinker, limestone is calcined into lime in a process that requires high heat and produces CO₂.

  • The ratio of the actual electricity an energy technology generates over a period of time to the maximum it could have produced if it operated at full capacity continuously.

  • A four-wheeled passenger vehicle.

  • Average number of people traveling in a car per trip.

  • Technologies that collect CO₂ before it enters the atmosphere, preventing emissions at their source. Collected CO₂ can be used onsite or in new products, or stored long term to prevent release.

  • A greenhouse gas that is naturally found in the atmosphere. Its atmospheric concentration has been increasing due to human activities, leading to warming and climate impacts.

  • Total GHG emissions resulting from a particular action, material, technology, or sector.

  • Amount of GHG emissions released per activity or unit of production. 

  • A marketplace where carbon credits are purchased and sold. One carbon credit represents activities that avoid, reduce, or remove one metric ton of GHG emissions.

  • A colorless, odorless gas released during the incomplete combustion of fuels containing carbon. Carbon monoxide can harm health and be fatal at high concentrations.

  • The time it takes for the emissions reduction from a measure to equal the emissions invested in implementing the measure.

  • Activities or technologies that pull CO₂ out of the atmosphere, including enhancing natural carbon sinks and deploying engineered sinks.

  • Long-term storage of carbon in soils, sediment, biomass, oceans, and geologic formations after removal of CO₂ from the atmosphere or CO₂ capture from industrial and power generation processes.

  • carbon capture and storage

  • carbon capture, utilization, and storage

  • A binding ingredient in concrete responsible for most of concrete’s life-cycle emissions. Cement is made primarily of clinker mixed with other mineral components.

  • chlorofluorocarbon

  • methane

  • Energy sources that have little to no negative environmental or climate impacts during operation relative to fossil fuel–based energy sources.

  • Gases or particles that have a planet-warming effect when released to the atmosphere. Some climate pollutants also cause other forms of environmental damage.

  • A binding ingredient in cement responsible for most of the life-cycle emissions from cement and concrete production.

  • A waste management process where waste is made into the same original product, preserving quality and value so materials can be reused multiple times while keeping resources in continuous use.

  • carbon monoxide

  • Neighbors, volunteer organizations, hobbyists and interest groups, online communities, early adopters, individuals sharing a home, and private citizens seeking to support the solution.

  • A solution that potentially lowers the benefit of another solution through reduced effectiveness, higher costs, reduced or delayed adoption, or diminished global climate impact.

  • A farming system that combines reduced tillage, cover crops, and crop rotations.

  • A risk-sharing financial agreement in which two parties (e.g., renewable generator, government) guarantee a fixed price (e.g., electricity price). If market prices fluctuate, one party pays the other the difference.

  • carbon dioxide

  • A  measure standardizing the warming effects of greenhouse gases relative to CO₂. CO₂-eq is calculated as quantity (metric tons) of a particular gas multiplied by its GWP.

  • carbon dioxide equivalent

  • Plant materials left over after a harvest, such as stalks, leaves, and seed husks.

  • A granular material made by crushing broken or waste glass.

  • direct air capture

  • Financial agreements in which government creditors forgive a portion of debt in exchange for specific conservation commitments.

  • The process of cutting greenhouse gas emissions (primarily CO₂) from a particular sector or activity.

  • An industrial process that removes printing ink from used or waste paper fibers, creating clean pulp that can be turned into new paper products.

  • A solution that works slower than gradual solutions and is expected to take longer to reach its full potential.

  • Microbial conversion of nitrate into inert nitrogen gas under low-oxygen conditions, which produces the greenhouse gas nitrous oxide as an intermediate compound.

  • Greenhouse gas emissions produced as a direct result of the use of a technology or practice.

  • A window consisting of two glass panes separated by a sealed gap and typically filled with air or an inert gas to improve the heat flow resistance.

  • A waste management system that transforms waste into different products of lower quality and value, making materials harder to recycle again and limiting reuse.

  • Ability of a solution to reduce emissions or remove carbon, expressed in CO₂-eq per installed adoption unit. Effectiveness is quantified per year when the adoption unit is cumulative over time.

  • A process that uses electric current to drive a reaction, such as using electricity to split water molecules into hydrogen and oxygen.

  • Greenhouse gas emissions accrued over the lifetime of a material or product, including as it is produced, transported, used, and disposed of.

  • Solutions that work faster than gradual solutions, front-loading their impact in the near term.

  • Methane produced by microbes in the digestive tracts of ruminant livestock, such as cattle, sheep and goats.

  • U.S. Environmental Protection Agency

  • expanded polystyrene

  • environmental, social, and governance

  • exchange-traded fund

  • A process triggered by an overabundance of nutrients in water, particularly nitrogen and phosphorus, that stimulates excessive plant and algae growth and can harm aquatic organisms.

  • Electric vehicle

  • An ecological process that releases water into the atmosphere as a gas from soil and ice (evaporation) and plants (transpiration).

     

  • The scientific literature that supports our assessment of a solution's effectiveness.

  • A group of human-made molecules that contain fluorine atoms. They are potent greenhouse gases with GWPs that can be hundreds to thousands times higher than CO₂.

  • Food, agriculture, land, and ocean

  • Food and Agriculture Organization of the United Nations

  • feed conversion ratio

  • The efficiency with which an animal converts feed into increased body mass, measured as the ratio of the weight of the feed given to weight gain. Lower FCR means less feed for the same growth.

  • Raw material inputs for manufacturing, processing, and managing waste.

  • Containing or consisting of iron.

  • A measure of fishing activity over time and area, commonly measured by number of trips, vessel time, or gear deployed.

  • food loss and waste

  • Food discarded during pre-consumer supply chain stages, including production, harvest, and processing.

  • Food discarded during pre-consumer supply chain stages, including production, harvest, and processing, along with food discarded wt the retail and consumer stages of the supply chain.

  • Food discarded at the retail and consumer stages of the supply chain.

  • Combustible materials found in Earth's crust that can be burned for energy, including oil, natural gas, and coal. They are formed from decayed organisms through prehistoric geological processes.

  • Unintentional leaks of gases or vapor into the atmosphere.

  • Unintentional leaks of gases or vapor into the atmosphere.

  • A group of countries representing the majority of the world's population, trade, and GDP. There are 19 member countries plus the European Union and the African Union

  • greenhouse gas

  • gigajoule or billion joules

  • The glass layers or panes in a window.

  • A measure of how effectively a gas traps heat in the atmosphere relative to CO₂. GWP converts greenhouse gases into CO₂-eq emissions based on their 20- or 100-year impacts.

  • A solution that has a steady impact on the atmosphere. Effectiveness is expected to be constant over time rather than having a higher impact in the near or long term.

  • A fixed income debt instrument focused on sustainable projects. Green bonds work in the same manner as traditional bonds and may be issued by corporations, financial institutions, and governments.

  • Biomass discarded during landscaping and gardening.

  • A gas that traps heat in the atmosphere, contributing to climate change.

  • The makeup of electricity generation on a power grid, showing the share contributed by various energy sources (e.g., coal, natural gas, nuclear, wind, solar, hydro) relative to total electricity production.

  • metric gigatons or billion metric tons

  • global warming potential

  • hectare

  • household air pollution

  • hydrochlorofluorocarbon

  • Number of years a person is expected to live without disability or other limitations that restrict basic functioning and activity.

  • A unit of land area comprising 10,000 square meters, roughly equal to 2.5 acres.

  • Hybrid electric car

  • hydrofluorocarbon

  • hydrofluoroolefin

  • hydrofluoroolefin

  • Particles and gases released from use of polluting fuels and technologies such as biomass cookstoves that cause poor air quality in and around the home.

  • heating, ventilation, air conditioning, and refrigeration

  • Organic compounds that contain hydrogen and carbon.

  • Human-made F-gases that contain hydrogen, fluorine, and carbon. They typically have short atmospheric lifetimes and GWPs hundreds or thousands times higher than CO₂. 

  • Human-made F-gases that contain hydrogen, fluorine, and carbon, with at least one double bond. They have low GWPs and can be climate-friendly alternatives to HFC refrigerants.

  • Hydrogen is a gas that can be a fuel, feedstock, or means of storing energy. It generates water instead of GHG when burned, but the process of producing it can emit high levels of GHGs. 

  • Hydrogen is a gas that can be a fuel, feedstock, or means of storing energy. It generates water instead of GHG when burned, but the process of producing it can emit high levels of GHGs. 

  • A recycling process that separates fibers from contaminants for reuse. Paper or cardboard is mixed with water to break down fibrous materials into pulp.

  • internal combustion engine

  • Aerobic decomposition of organic waste in a sealed container or bin/bay system. 

  • Greenhouse gas emissions produced as a result of a technology or practice but not directly from its use.

  • Device used to power vehicles by the intake, compression, combustion, and exhaust of fuel that drives moving parts.

  • The annual discount rate that balances net cash flows for a project over time. Also called IRR, internal rate of return is used to estimate profitability of potential investments.

  • Individuals or institutions willing to lend money in search of a return on their investment.

  • Intergovernmental Panel on Climate Change

  • Indigenous People’s Land

  • Integrated pest management.

  • internal rate of return

  • International Union for Conservation of Nature

  • The most comprehensive global list of species threatened with extinction, maintained by the International Union for Conservation of Nature.

  • International agreement adopted in 2016 to phase down the use of high-GWP HFC F-gases over the time frame 2019–2047.

  • A measure of energy equivalent to the energy delivered by 1,000 watts of power over one hour.

  • kiloton or one thousand metric tons

  • kilowatt-hour

  • A land-holding system, e.g. ownership, leasing, or renting. Secure land tenure means farmers or other land users will maintain access to and use of the land in future years.

  • Gases, mainly methane and CO₂, created by the decomposition of organic matter in the absence of oxygen.

  • levelized cost of electricity

  • leak detection and repair

  • Regular monitoring for fugitive methane leaks throughout oil and gas, coal, and landfill sector infrastructure and the modification or replacement of leaking equipment.

  • Relocation of emissions-causing activities outside of a mitigation project area rather than a true reduction in emissions.

  • The rate at which solution costs decrease as adoption increases, based on production efficiencies, technological improvements, or other factors.

  • Percent decrease in costs per doubling of adoption.

  • A metric describing the expected break-even cost of generating electricity per megawatt-hour ($/MWh), combining costs related to capital, operation, and fuel (if used) and dividing by total output over the generator's lifetime.

  • landfill gas

  • Greenhouse gas emissions from the sourcing, production, use, and disposal of a technology or practice.

  • The total weight of an organism before any meat processing.

  • low- and middle-income countries

  • liquefied petroleum gas

  • land use change

  • A measure of the amount of light produced by a light source per energy input.

  • live weight

  • marginal abatement cost curve

  • Livestock grazing practices that strategically manage livestock density, grazing intensity, and timing. Also called improved grazing, these practices have environmental, soil health, and climate benefits, including enhanced soil carbon sequestration.

  • A tool to measure and compare the financial cost and abatement benefit of individual actions based on the initial and operating costs, revenue, and emission reduction potential.

  • Defined by the International Union for Conservation of Nature as: "A clearly defined geographical space, recognised, dedicated and managed, through legal or other effective means, to achieve the long-term conservation of nature with associated ecosystem services and cultural values." References to PAs here also include other effective area-based conservation measures defined by the IUCN. 

  • A facility that receives recyclable waste from residential, commercial, and industrial sources; separates, processes, and prepares them; and then sells them to manufacturers for reuse in new products.

  • A measure of energy equivalent to the energy delivered by one million watts of power over one hour.

  • A greenhouse gas with a short lifetime and high GWP that can be produced through a variety of mechanisms including the breakdown of organic matter.

  • A measure of mass equivalent to 1,000 kilograms (~2,200 lbs).

  • million hectares

  • Soils mostly composed of inorganic materials formed through the breakdown of rocks. Most soils are mineral soils, and they generally have less than 20% organic matter by weight.

  • A localized electricity system that independently generates and distributes power. Typically serving limited geographic areas, mini-grids can operate in isolation or interconnected with the main grid.

  • Reducing the concentration of greenhouse gases in the atmosphere by cutting emissions or removing CO₂.

  • megajoule or one million joules

  • Percent of trips made by different passenger and freight transportation modes.

  • Marine Protected Area

  • materials recovery facility

  • Municipal solid waste

  • megaton or million metric tons

  • Materials discarded from residential and commercial sectors, including organic waste, glass, metals, plastics, paper, and cardboard.

  • Megawatt-hour

  • micro wind turbine

  • square meter kelvins per watt (a measure of thermal resistance, also called R-value)

  • The enclosed housing at the top of a wind turbine tower that contains the main mechanical and electrical components of the turbine.

  • A commitment from a country to reduce national emissions and/or sequester carbon in alignment with global climate goals under the Paris Agreement, including plans for adapting to climate impacts.

  • A gaseous form of hydrocarbons consisting mainly of methane.

  • Chemicals found in nature that are used for cooling and heating, such as CO₂, ammonia, and some hydrocarbons. They have low GWPs and are ozone friendly, making them climate-friendly refrigerants.

  • Microbial conversion of ammonia or ammonium to nitrite and then to nitrate under aerobic conditions.

  • A group of air pollutant molecules composed of nitrogen and oxygen, including NO and NO₂.

  • A greenhouse gas produced during fossil fuel combustion and agricultural and industrial processes. N₂O is hundreds of times more potent than CO₂ at trapping atmospheric heat, and it depletes stratospheric ozone.

  • Metals or alloys that do not contain significant amounts of iron.

  • Social welfare organizations, civic leagues, social clubs, labor organizations, business associations, and other not-for-profit organizations.

  • A material or energy source that relies on resources that are finite or not naturally replenished at the rate of consumption, including fossil fuels like coal, oil, and natural gas.

  • nitrogen oxides

  • nitrous oxide

  • The process of increasing the acidity of seawater, primarily caused by absorption of CO₂ from the atmosphere.

  • An agreement between a seller who will produce future goods and a purchaser who commits to buying them, often used as project financing for producers prior to manufacturing.

  • Waste made of plant or animal matter, including food waste and green waste.

  • organic waste

  • Protected Area

  • Productive use of wet or rewetted peatlands that does not disturb the peat layer, such as for hunting, gathering, and growing wetland-adapted crops for food, fiber, and energy.

  • A legally protected area that lacks effective enforcement or management, resulting in minimal to no conservation benefit.

  • Airborne particles composed of solids and liquids.

  • A measure of transporting one passenger over a distance of one kilometer.

  • Incentive payments to landowners or managers to conserve natural resources and promote healthy ecological functions or ecosystem services.

  • Small, hardened pieces of plastic made from cooled resin that can be melted to make new plastic products.

  • The longevity of any greenhouse gas emission reductions or removals. Solution impacts are considered permanent if the risk of reversing the positive climate impacts is low within 100 years.

  • Payments for ecosystem services

  • A mixture of hydrocarbons, small amounts of other organic compounds, and trace amounts of metals used to produce products such as fuels or plastics.

  • Per- and polyfluoroalkyl substances, a class of synthetic chemicals that do not degrade easily in the environment. They can pollute the environment and can have negative impacts on human health.

  • Reduce the use of a material or practice over time.

  • Eliminate the use of a material or practice over time.

  • Plug-in hybrid electric car

  • Private, national, or multilateral organizations dedicated to providing aid through in-kind or financial donations.

  • An atmospheric reaction among sunlight, VOCs, and nitrogen oxide that leads to ground-level ozone formation. Ground-level ozone, a component of smog, harms human health and the environment.

  • The process by which sunlight is converted into electricity. When light hits certain materials, such as those in solar panels, it mobilizes electrons, creating an electric current.

  • polyisocyanurate

  • The adjustment of turbine blade angles around their long axis in which a control system rotates blades slightly forward or backward to regulate wind capture and optimize electricity generation.

  • passenger kilometer

  • particulate matter

  • Particulate matter 2.5 micrometers or less in diameter that can harm human health when inhaled.

  • Elected officials and their staff, bureaucrats, civil servants, regulators, attorneys, and government affairs professionals.

  • System in a vehicle that generates power and delivers it to the wheels. It typically includes an engine and/or motor, transmission, driveshaft, and differential.

  • Purchase Power Agreement.

  • People who most directly interface with a solution and/or determine whether the solution is used and/or available. 

  • A substance that is the starting material for a chemical reaction that forms a different substance.

  • Extraction of naturally occurring resources from the Earth, including mining, logging, and oil and gas refining. These resources can be used in raw or minimally processed forms to produce materials.

  • The process of converting inorganic matter, including carbon dioxide, into organic matter (biomass), primarily by photosynthetic organisms such as plants and algae.

  • Defined by the International Union for the Conservation of Nature as "A clearly defined geographical space, recognised, dedicated and managed, through legal or other effective means, to achieve the long-term conservation of nature with associated ecosystem services and cultural values". References to PAs here also include other effective area-based conservation measures defined by the IUCN. 

  • A process that separates and breaks down wood and other raw materials into fibers that form pulp, the base ingredient for making paper products.

  • polyurethane

  • Long-term contract between a company (the buyer) and a renewable energy producer (the seller).

  • photovoltaic

  • research and development

  • A situation in which improvements in efficiency or savings lead to consumers increasing consumption, partially or fully offsetting or exceeding the emissions or cost benefits.

  • renewable energy certificate

  • Chemical or mixture used for cooling and heating in refrigeration, air conditioning, and heat pump equipment. Refrigerants absorb and release heat as they move between states under changing pressure.

  • The amount of refrigerant needed for a particular refrigeration, air conditioning, or heat pump system.

  • A group of approaches to farming and ranching that emphasizes enhancing the health of soil by restoring its carbon content and providing other benefits to the farm and surrounding ecosystem.

  • A solution that can increase the beneficial impact of another solution through increased effectiveness, lower costs, improved adoption, enhanced global climate impact, and/or other benefits to people and nature.

  • A material or energy source that relies on naturally occuring and replenishing resources such as plant matter, wind, or sunlight.

  • A market-based instrument that tracks ownership of renewable energy generation.

  • The moldable form of raw plastic material, created by melting down waste or virgin plastics and serving as the building block for creating new plastic goods.

  • A class of animals with complex stomachs that can digest grass. Most grazing livestock are ruminants including cows, sheep, and goats along with several other species.

  • sustainable aviation fuel

  • A wetland ecosystem regularly flooded by tides and containing salt-tolerant plants, such as grasses and herbs.

  • Very large or small numbers are formatted in scientific notation. A positive exponent multiplies the number by powers of ten; a negative exponent divides the number by powers of ten.

  • Seasonal coefficient of performance

  • Sustainable Development Goals

  • Average units of heat energy released for every unit of electrical energy consumed, used to measure heat pump efficiency.

  • A practice in which multiple utility companies own and operate high-voltage power lines, sharing both costs and benefits.

  • A window consisting of one glass pane without any additional insulating layers.

  • Small-scale family farmers and other food producers, often with limited resources, usually in the tropics. The average size of a smallholder farm is two hectares (about five acres).

  • soil organic carbon

  • Carbon stored in soils, including both organic (from decomposing plants and microbes) and inorganic (from carbonate-containing minerals).

  • Carbon stored in soils in organic forms (from decomposing plants and microbes). Soil organic carbon makes up roughly half of soil organic matter by weight.

  • Biologically derived matter in soils, including living, dead, and decayed plant and microbial tissues. Soil organic matter is roughly half carbon on a dry-weight basis.

  • soil organic matter

  • A substance that takes up another liquid or gas substance, either by absorbtion or adsorption.

  • sulfur oxides

  • sulfur dioxide

  • The rate at which a climate solution physically affects the atmosphere after being deployed. At Project Drawdown, we use three categories: emergency brake (fastest impact), gradual, or delayed (slowest impact).

  • Climate regions between latitudes 23.4° to 35° above and below the equator characterized by warm summers and mild winters.

  • A polluting gas produced primarily from burning fossil fuels and industrial processes that directly harms the environment and human health.

  • A group of gases containing sulfur and oxygen that predominantly come from burning fossil fuels. They contribute to air pollution, acid rain, and respiratory health issues.

  • Processes, people, and resources involved in producing and delivering a product from supplier to end customer, including material acquisition.

  • Sport utility vehicle

  • metric ton

  • metric tons

  • Technology developers, including founders, designers, inventors, R&D staff, and creators seeking to overcome technical or practical challenges.

  • Climate regions between 35° to 50° above and below the equator characterized by moderate mean annual temperatures and distinct seasons, with warm summers and cold winters.

  • A measure of energy equivalent to the energy delivered by one trillion watts of power over one hour.

  • A measure of how well a material prevents heat flow, often called R-value or RSI-value for insulation. A higher R-value means better thermal performance.

  • Individuals with an established audience for their work, including public figures, experts, journalists, and educators.

  • Charges for disposal of materials paid to facility operators. Fees can be charged per ton of waste disposed or based on economic indicators such as the Consumer Price Index.

  • A window consisting of three panes of glass separated by two insulating inert gas-filled layers, providing more heat flow resistance than single or double glazing.

  • Low-latitude (23.4°S to 23.4°N) climate regions near the Equator characterized by year-round high temperatures and distinct wet and dry seasons.

  • Terawatt, equal to 1,000 gigawatts

  • terawatt-hour

  • United Nations

  • United Nations Environment Programme

  • Self-propelled machine for transporting passengers or freight on roads.

  • A measure of one vehicle traveling a distance of one kilometer.

  • Aerobic decomposition of organic waste by earthworms and microorganisms.

  • vehicle kilometer

  • volatile organic compound

  • Gases made of organic, carbon-based molecules that are readily released into the air from other solid or liquid materials. Some VOCs are greenhouse gases or can harm human health.

  • watt (a measure of power or energy transfer.)

  • Landscape waste, storm debris, wood processing residues, and recovered post-consumer wood.

  • A measure of power equal to one joule per second.

  • Aerobic decomposition of organic waste in long, narrow rows called windrows. Windrows are generally twice as long as they are wide.

  • A subset of forest ecosystems that may have sparser canopy cover,  smaller-stature trees, and/or trees characterized by basal branching rather than a single main stem.

  • extruded polystyrene

  • The rotation of the nacelle (the enclosed housing at the top of a wind turbine tower that contains the main mechanical and electrical components of the turbine) so that the rotor blades are always facing directly into the wind.

  • year

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