The report analyzes how different states emit greenhouse gases (GHGs) by looking at factors like population, income, and emissions intensity. GHG intensity measures how much GHGs a state produces compared to its economy. Most GHGs come from carbon dioxide (CO2), which is mainly produced by using energy like coal. States with more coal usage have higher carbon emissions. States can lower their GHG emissions by using energy more efficiently and by having cleaner energy sources. Between 1990 and 2000, the United States decreased its GHG emissions intensity by 1.6% each year.