Nature is crucial for human well-being and sustainable development. While ecosystem services (ES) have been extensively studied, understanding their equitable distribution among societal groups remains a critical gap. Growing societal inequality underscores the importance of addressing this gap for environmental justice. Globally, projected ES declines are most severe in developing countries, and existing case studies demonstrate that ES benefits often favor wealthier groups. For instance, indigenous populations rarely benefit from water quality offset projects, and poorer households in China have less access to ES than wealthier ones. Even in the US, the benefits of urban vegetation's cooling effect are unequally distributed. This raises concerns about the uneven distribution of natural capital and its associated benefits. Distributional analyses in economics have primarily focused on wealth and income or the impacts of negative externalities on public goods. The environmental justice field has documented disparities in exposure to environmental hazards among minority and lower-income populations. However, these analyses are rarely applied to non-market ES benefits. Most ES studies quantify services in biophysical terms or total economic value, masking the unequal distribution of benefits among societal groups. Disaggregating ES benefits is essential for identifying who benefits and who loses from decisions impacting ES provision, allowing for the development of policies that distribute benefits equitably or compensate for losses. Several conceptual frameworks exist for relating nature's contributions to people, often using terms like "supply," "demand," and "benefit." This study follows this convention, defining supply as a biophysical measure of an ecosystem function, demand as the human need or desire for that service, and benefit as a function of both supply and demand. In the US, projected land cover changes (loss of natural cover and expansion of cropland and urban areas) and population shifts (urban growth and rural decline) will significantly alter the supply and demand for multiple ES. These changes are likely to create mismatches between supply and demand, disproportionately affecting marginalized groups.

The study references numerous works highlighting the unequal distribution of ecosystem services. Studies in Peru and China demonstrate how benefits are skewed towards wealthier groups, while research in US cities shows a correlation between income and access to the cooling benefits of urban vegetation. The authors note a gap in applying distributional analyses to non-market ES benefits, despite extensive research on wealth distribution and environmental externalities. Existing ES assessments often aggregate benefits spatially or not at all, masking inequities. Several conceptual frameworks for understanding ES supply, demand, and benefits are mentioned, along with the existing literature predicting future changes in land cover and population in the US, leading to potential mismatches between ES supply and demand.

This study projects changes in the supply, demand, and benefits of three ES (clean air, West Nile virus protection, and crop pollination) in every US county between 2020 and 2100. It uses the USGS FOREcasting SCEnarios of Land-Use Change (FORE-SCE) dataset for land cover projections and the US EPA Integrated Climate and Land Use Scenarios (ICLUS) dataset for population projections. These are coupled with county-level income and demographic projections, modulated by four IPCC Special Report on Emissions Scenarios (SRES): A1B, A2, B1, and B2. **Air quality:** The Intervention Model for Air Pollution (InMAP) was used to estimate changes in air quality based on land cover changes and emissions factors from MEGAN v2.1 and the US National Emissions Inventory. The model predicts PM2.5 concentrations and associated premature mortalities. **Crop pollination:** The Lonsdorf et al. model (LEM) was employed to calculate the supply of bee pollination services, using land cover data and a distance-weighted average abundance of surrounding nests. Demand was determined by the area of pollinator-dependent crops. Benefit was calculated as the product of supply and demand. **Vector-borne disease control (West Nile Virus):** Statistical models were developed using data on annual average WNV cases per 100,000 people and land cover proportions. The conterminous US was divided into EPA Ecoregions, and models were created for each. Generalized linear models with Gamma distributions were fitted, and the models were used to predict WNV incidence under different land cover scenarios. Supply was considered as the avoided risk of exposure, and demand was the projected human population. The study disaggregates projected changes in ES benefits across rural/urban communities, income quintiles, regions, and racial groups (Black, Hispanic, Other, White). For demographic groups, ES benefits were partitioned based on the proportion of each group within a county. Adjustments were made to account for racial disparities between farmers and the general population for crop pollination.

The study projects declines in US ES benefits between 2020 and 2100 across nearly all scenarios, with the most significant declines under scenario A2. The magnitude of decline varies by ES and scenario. At the county level, ES mismatches are expected where supply decreases and demand increases. Analysis reveals that the largest differences in projected ES benefits occur between income and racial groups, rather than geographic regions. **Aggregate trends:** Overall, significant losses in benefits are projected across all three ecosystem services in most scenarios. Scenario A2 shows the most significant losses, with the exception of a slight increase in WNV disease control benefits. The results for the other scenarios are presented in the supplemental information. **County-level trends:** County-level analysis shows considerable variability in projected changes in ES supply and demand. The most notable mismatches occur in areas where supply decreases while demand increases. For air quality, both supply and demand decrease in most counties due to land-use changes and population shifts, but demand increases in urban areas leading to a net loss nationally. For crop pollination, demand increases in most counties due to expanding cropland, while supply decreases because of forest loss. For WNV control, demand decreases in most counties, but increases in urban centers, while supply generally remains constant or increases. **Distribution among groups:** The study highlights stark differences in the distribution of ES benefit changes among different groups. Rural counties generally see increases in air quality and WNV control benefits and decreases in crop pollination, while the opposite is true for urban counties. Lower-income counties experience the most substantial losses in air quality and WNV benefits, while higher-income counties see gains. Non-white communities are projected to experience substantial losses across all three ES, while white communities experience gains. Regional differences in ES benefit changes are less pronounced than those among income and racial groups.

The findings demonstrate that projected ES declines will disproportionately impact already marginalized communities in the US, exacerbating existing environmental inequalities. This aligns with broader evidence that marginalized groups face disproportionate exposure to environmental hazards. The study emphasizes the need for disaggregating ES benefits to reveal these inequities, as traditional spatial or regional aggregations often mask them. The disproportionate impact on marginalized groups stems mainly from the conversion of natural land cover in counties where these communities are projected to grow. This conversion negatively affects ES supply (except in some cases of WNV). As the US becomes more racially diverse and income inequality increases geographically, these declines in ES supply will disproportionately affect non-white and low-income communities. The study also discusses potential responses to ES losses, including direct costs (increased mortality, crop yield losses), substitution with non-nature-based solutions, and emigration. It acknowledges that the current ES distribution is not equitable, and the projected changes will likely exacerbate existing inequalities. The study notes complexities in the crop pollination case, where farmers are direct beneficiaries but consumers benefit indirectly, and the geographic disconnect between production and consumption is not accounted for.

This study highlights the inequitable distribution of projected losses in ecosystem services in the US, disproportionately affecting non-white and lower-income populations. The findings underscore the importance of disaggregating ES analyses to reveal these inequalities and advocate for targeted conservation and land-use policies that consider both ES supply and the vulnerability of specific populations. Future research should focus on improving ES models, incorporating climate change impacts, and validating ES model predictions empirically. These findings offer a crucial call to action for land owners, researchers, decision-makers, and social justice groups to work towards equitable distribution of ecosystem services.

The study acknowledges several limitations. First, the land cover and population projections are not best-estimates but represent a range of possible outcomes, and there is a lack of consensus among different land-cover projection datasets. Second, the national-scale analysis necessitates the use of simplified models and readily available data, leading to potential trade-offs in model complexity. The study did not incorporate climatic variables or climate change impacts on land cover change, ES supply, and demand, which might underestimate the projected disparities. Finally, the modeling approach uses generalized parameters, which may not fully capture the heterogeneity of impacts within counties.