Less coal, more oil: Climate pollution trends by state

Greenhouse gas emissions in the United States in 2022 were 15% lower than in 2005. Hiding behind the overall decline in greenhouse gas emissions from 2005 to 2022 is tremendous variation in emission trends in different states, according to data from the U.S. Environmental Protection Agency’s (EPA) state greenhouse gas inventory. These variations highlight the critical role of state and regional policies in America’s efforts to reduce greenhouse gas emissions – especially given new uncertainty about federal leadership on climate – and point to the next set of climate policy challenges facing the states and the nation.  

America’s success in reducing greenhouse gas emissions since 2005 has been largely driven by the retirement of many coal-fired power plants, a trend supported by tougher environmental standards for power plant emissions and growing competition from renewable energy and other forms of power generation.

On the other hand, increased oil and gas production caused emissions to rise in a number of states. The takeaway: major future emission reductions are not likely to come from the same sources as the last two decades, since coal is now a much smaller share of overall emissions. Maintaining momentum on climate protection will require not just the continued elimination of coal-fired power plants but also a laser focus on reducing emissions from oil and gas production and consumption. 

44 states have cut climate change pollution

Between 2005 and 2022, total greenhouse gas pollution decreased in 44 states plus the District of Columbia and increased in six. The biggest percentage emission reductions from 2005 to 2022 occurred in Maryland (36%), the District of Columbia (34%), Maine (33%), New Hampshire (33%) and Georgia (30%). In the six states where pollution rose, increases were 0.2% in Mississippi, 3% in Texas, 5% in Nebraska, 15% in South Dakota, 20% in Idaho and 23% in North Dakota.

On a per capita basis, emissions declined 25% nationally from 2005 to 2022, falling in every state except North Dakota. The locations with the biggest drops in per capita emissions were the District of Columbia (44% decrease), Georgia (43% decrease), Maryland (42% decrease), Nevada (40% decrease), Tennessee (38% decrease) and New Hampshire (37% decrease). Per capita emissions increased by 2% in North Dakota, and only modest reductions in per capita emissions were achieved in Mississippi (1% decrease), South Dakota (2% decrease), Louisiana (4% decrease) and Nebraska (6% decrease). 

With the United States having committed to reducing greenhouse gas emissions by 50-52% below 2005 levels by 2030, there is still much work remaining to be done to cut emissions, even in states that have thus far seen the steepest declines. And the EPA’s data shows that there is still room to cut greenhouse gas emissions in every state, as evidenced by the states with the lowest per-capita emissions. On the whole, the United States released an average of 19 metric tons of carbon dioxide equivalent per person in 2022, but a number of places emitted a fraction of that amount, such as the District of Columbia (4.8 metric tons of carbon dioxide equivalent), Massachusetts (9.5), Maryland (9.9), New York (9.9) and California (10.2). On the other hand, several states emitted much more than the average, including Wyoming (143.8 metric tons of carbon dioxide equivalent per person), North Dakota (113.3), West Virginia (64.7), Alaska (55.4) and Louisiana (48.5).

Reduced pollution from electricity generation helped total emissions decline in some states

Declining pollution from electricity generation was a major factor in the five states with the biggest percentage declines in emissions from 2005 to 2022. Pollution from electricity generation dropped by 66% in Maryland, 93% in the District of Columbia, 51% in Maine, 67% in New Hampshire and 53% in Georgia. 

Three of these states – Maryland, Maine and New Hampshire – are members of the Regional Greenhouse Gas Initiative (RGGI), an agreement by 11 northeastern and mid-Atlantic states to reduce pollution from power plants. Collectively, the initial 10 RGGI states (excluding Pennsylvania) cut pollution from power plants by 50% from 2005 to 2023, with much of that reduction resulting from the closure of coal-fired power plants. New England’s last remaining coal-fired power plant, for example, is scheduled to close in 2028. The District of Columbia’s electricity emissions dropped because two power plants that burned petroleum closed, while in Georgia three of the state’s largest five coal-fired power plants closed or were converted to burn methane gas.

More oil and gas production and agricultural activity caused pollution to increase in six states

The reasons for emissions increases were more varied and include, depending on the state, rising oil and gas production and increased agricultural emissions.

North Dakota’s 23% increase in total pollution was led by the industrial sector, where pollution more than doubled. The biggest increase in industrial emissions was fugitive emissions from petroleum exploration and production. Emissions from agriculture, the third-largest source, also increased. 

Another state with rising agricultural emissions was South Dakota, whose emissions increased by 15% overall. Emissions from agriculture, which accounts for more than half of the state’s emissions, increased by 15%, driven by increases in nitrous oxide from soil management and methane from dairy operations. Emissions increased in every other sector of the economy, too, except for electricity generation. 

In Nebraska, overall emissions increased by 5%, with increases in every sector of the economy except electricity generation. Agricultural emissions, the largest source of pollution in the state, increased by 2%, while industrial and commercial emissions rose 47% and 38%, respectively. Industrial emissions increased because of growth in natural gas combustion.

Emissions in Texas increased 3%. Though emissions from electricity generation declined, all other sources increased. 

Fossil fuel production and use caused high per capita emissions in some states

States with high per capita emissions generally have industrial or electric sectors that emit large amounts of pollution. 

The three states with the highest per capita emissions are Wyoming, North Dakota and West Virginia. In all three, electricity generation is the largest source of emissions, followed by industrial emissions. All three states are leading producers of oil, gas and/or coal: Wyoming and West Virginia are the largest and second-largest producers of coal, respectively, and North Dakota is the nation’s third largest producer of oil. As a result, the biggest sources of industrial emissions in those states include fugitive emissions from oil, gas and/or coal production.

Alaska and Louisiana, which have the next highest per capita emissions, are also major fossil fuel producers: Alaska is fifth in the nation for oil production and Louisiana is third for natural gas. In those two states, industrial emissions are the largest overall source of emissions. 

States with low per capita emissions all have relatively low emissions from the electric and industrial sectors. In the four states with lowest per capita emissions, transportation is the largest source of emissions. 

The states with the highest per capita emissions produce energy that is consumed both locally and in other states. If emissions were calculated based on consumption, emissions would appear lower in these energy-producing states and higher in other states.

The biggest future emission reductions will come from transportation and the industrial sector

From 2005 to 2022, the decline of coal-fired electricity generation was an important factor in emission reductions nationally and in many states. Retiring coal-fired power plants enabled many states in the northeast and mid-Atlantic to achieve some of the largest emission declines in the nation. Now, those states will have to look to other sectors for future emission reductions. Other states that have retired only some of their coal-fired power plants will soon be faced with the same transition in priorities. 

Emission reduction efforts will need to target the transportation sector, now the largest source of pollution in half of the 50 states. Options include rapidly replacing polluting internal combustion engine vehicles with electric vehicles, as well as investing in improvements that make walking, biking and transit more convenient and practical, thus allowing people the option of driving less. 

States with extensive industrial pollution, including from fossil fuel production, will need to reduce oil and gas production and to transition industrial facilities, such as steel mills, to cleaner production methods. 

Additional emission reductions may be obtained by improving energy efficiency in the residential and commercial sectors and by replacing gas furnaces and water heaters with electric options, such as heat pumps. Energy efficiency and electrification will lower natural gas consumption and emissions from homes and businesses. 

The success of some states in reducing global warming pollution over the past decade and a half from power plants demonstrates that ambitious emission reductions are achievable. The low level of per capita emissions in several states confirms this. By strengthening state and federal commitments to phasing coal-fired power plants out of the electricity mix and taking on the challenge of cutting emissions in transportation, industry and agriculture, the United States can move even closer to the goal of dramatically reducing our impact on the climate.

Methodology: This analysis uses 2005 and 2022 state emission data broken down by economic sector from EPA’s Greenhouse Gas Inventory. It excludes emissions from the Land-Use Change and Forestry sector. EPA uses 100-year global warming potentials for all pollutants. EPA acknowledges that its methane estimates for the oil and gas production sectors may be incomplete, in part because of the challenges of incorporating episodic events. This may result in underreporting of emissions from oil- and gas-producing states. Recent independent measurements of specific regions suggest methane leakage rates may be four times as high as what EPA assumes for those areas.