This week, the US Energy Information Agency (EIA) released a report on the carbon dioxide (CO2) emissions of each state between 2000 and 2015. The good news? CO2 emissions dropped in 41 states, with Maine taking home the prize for the greatest percentage decrease in emissions (by 25 percent). Ohio, meanwhile, showed the greatest absolute decrease, using 51.7 million fewer metric tons of CO2 emissions in 2015 than it did in 2000.
The bad news? Nine states saw increases in CO2 emissions over the same period. Nebraska was one of the worst offenders, with a 22-percent increase in carbon emissions between 2000 and 2015. Though Nebraska's population grew by roughly 200,000 in those 15 years, Kansas also welcomed about 200,000 people into its state between 2000 and 2015, and it cut emissions by 17.2 percent. (Kansas' success is probably in part due to the state's embrace of wind, where "wind energy has grown from less than 1 percent of net electricity generation in 2005 to 24 percent in 2015, making wind the state's second largest power provider, after coal," the EIA writes.)
The EIA cautions against evaluating these emissions numbers as a direct reflection of how green a state is, though, because the agency only counted energy-related emissions in the state they were created. That doesn't account for exporting energy across state lines. If one state uses only renewables but buys a considerable supply of electricity from a coal plant in a neighboring state, the neighboring state bears the burden for all those emissions.