Using the approach described in the “Methods” section, we identify U.S. counties with the highest combined exposure and sensitivity scores in six fossil fuel-related activities: coal mining, coal power, petroleum extraction , petroleum refining, natural gas extraction and gas power. In Table 1, we present the 10 highest counties in each category; in Supplementary Information, Tables SI1-6, we provide tables for each category in which we include the top 40 counties (full data is available in the data appendix), as well as an overall score that combines the six measures (table SI8). In these tables, we present the final measurements of exposure, sensitivity, and exposure times sensitivity, the latter in raw and percentile form. In Fig. 1, we map results for all activity and fuel types, in which colored shading indicates the percentile of each US county’s exposure and sensitivity to a transition away from fossil fuels. Counties in the highest percentile for the combined measures of exposure and susceptibility are colored darkest, and counties with lower scores are colored lighter.
Because it is the most carbon-intensive fuel and has many substitutes in the electricity sector, coal will almost certainly be the fastest declining energy source under ambitious climate policies.5.40. Indeed, coal production in the United States has fallen dramatically in recent years, although most of that decline is due to market factors led by low-cost natural gas.41. Coal is produced primarily in the Intermountain West, Appalachia, and Illinois Basin, with limited production in other locations.
In 2019, more than a third of all US coal was produced in Campbell County, Wyoming. However, Campbell County scores very low on our sensitivity measures, indicating that it currently faces fewer environmental and socioeconomic challenges than most other US counties. Most other major coal-producing counties have significantly higher sensitivity scores, indicating relatively high rates of poverty and exposure to environmental loads often found in parts of Appalachia and Intermountain West.
Hundreds of coal-fired power generation units in the United States have retired over the past decades or are about to retire, and in the absence of widespread deployment of CCS, generation at coal will need to approach zero in coming decades to meet ambitious climate goals5,26,40. Because coal-fired power plants are widely distributed across the country, county-level exposure scores are lower than those seen in coal mining, which is more geographically concentrated. However, the sensitivity scores for these counties are very high, indicating high existing levels of poverty, low levels of education, and high exposure to environmental hazards. As with coal generation, exposure and susceptibility of power plant communities to coal is most prevalent in Appalachia. However, many counties in regions without coal production, such as Florida, North Carolina and Wisconsin, also score high on these measures.
Oil is the largest source of primary energy supply in the United States, and production has increased significantly over the past decade or so, led by parts of Texas, New Mexico and North Dakota. However, significant amounts of oil are produced in more than a dozen other states. Partly because of the economic benefits of recent growth in oil production, many of the most exposed counties have low sensitivity scores. For example, McKenzie County, ND produced more oil than any other US county in 2019, yet it only ranks in the 4th percentile for sensitivity.
Counties with the highest combined levels of exposure and susceptibility are concentrated in South and West Texas, where high levels of exposure are combined with relatively low income levels and high risk exposure environmental and climatic. For example, Karnes County in South Texas ranks in the top 90th percentile for our climate change indicators and the bottom 20th percentile for education indicators. Although they do not rank in the top 10 counties listed in Table 1, there is also high exposure and sensitivity for some counties in California, Louisiana, North Dakota, Utah, and Wyoming.
Oil refineries are essential components of today’s energy system, but they are also major polluters, both of greenhouse gases and air emissions that impose health problems on nearby populations.42. The United States is home to the largest fleet of oil refineries in the world43centered along the Gulf Coast and close to major population centers.
Reflecting the environmental loads from refineries and other heavy industries that are often concentrated around major ports, most counties with high levels of exposure also have high levels of sensitivity. Indeed, the six counties with the highest combined exposure and sensitivity scores each host major port facilities, where crude oil, petroleum products and other commodities are imported, refined and exported in large quantities. . In some counties (eg, Will County, IL; Contra Costa County, CA) with high levels of refining, these environmental loads are relatively low. However, our metrics are county-level aggregates and may not reflect the more localized sensitivities that likely exist at smaller geographic scales (e.g. tracts or census blocks).
Natural gas is produced on a large scale in hundreds of US counties, with major producing counties in Pennsylvania, Louisiana, Texas, Colorado, Ohio, Wyoming and New Mexico. Although less carbon-intensive than coal or oil on an energy-equivalent basis (assuming methane emissions are minimized), natural gas production in the United States and around the world is declining over the decades in the most ambitious climate scenarios.26.
As with oil production, some of the most exposed U.S. counties score relatively low on sensitivity metrics, partly due to the economic benefits of growing domestic natural gas production, and partly due to environmental burdens. and relatively low climate change risks. For example, the top two natural gas producing counties in 2019, Susquehanna and Washington counties in Pennsylvania, rank in the lower 50th percentile of our sensitivity score. However, other major producing counties in parts of Appalachia, Louisiana, and Texas show significantly higher sensitivity due to low economic indicators and high environmental and climate risk.
Like natural gas generation, gas-fired power plants will tend to last longer than coal due to their lower emissions intensity (if methane emissions are minimized). However, ambitious climate scenarios over the next few decades will require most gas-fired power plants to adopt CCS technologies, incorporate net-zero fuels such as biogas or hydrogen, or retire.26. Existing capacity is concentrated in and around urban centers, allowing producers to respond quickly to increased demand during peak periods (eg hot summer days).
Many of these urban centers also have high sensitivity scores due to a variety of factors, including climate and other environmental hazards (eg, Harris County, TX); high housing and energy loads (eg, Los Angeles County, California); and low levels of education associated with poor public health indicators (eg, Heard County, GA).
We believe this analysis provides the most comprehensive and policy-relevant information about how American communities might be affected by a transition away from fossil fuels. However, our work has several limitations that may be addressed by future research. First, we are not measuring adaptive capacity, which will have a dramatic impact on communities most resilient to shocks that reduce fossil fuel-based activities. Second, we do not attempt to identify counties where fossil fuel activities would be more or less economically competitive in a scenario of declining national or global demand for fossil fuels. Third, we do not assess the role that negative emissions technologies, CCS or other emerging technologies could play in extending the viability of fossil fuel extraction, processing and use in some locations. Finally, we do not attempt to assess the importance or assign weights to different measures in our construction of a vulnerability index. Future work could answer these questions, and many more, to enable a more equitable transition to a clean energy future.