Greenhouse gases refer to a set of naturally occurring or human generated gases that transform the atmosphere. Accumulating greenhouse gases in the atmosphere cause global warming by allowing more solar energy to reach the Earth’s surface and absorbing solar radiation. Humans generate most of the increased greenhouse gasses through actions such as burning fossil fuels and manufacturing chemicals. The most problematic gases include carbon dioxide, methane, nitrous oxide, and manufactured fluorinated gases.
In the United States, greenhouse gas emissions are regulated by the Environmental Protection Agency (EPA) and individual states to prevent pollution and global warming. Much of the regulations in the United States target specific emitters of greenhouse gases such as carbon dioxide from vehicles and power plants. The Clean Air Act (CAA) is the basis for the EPA’s broad regulations controlling greenhouse gas emissions after the Supreme Court ruled in Massachusetts v. EPA that the CAA requires the EPA to regulate greenhouse gas emissions. Many states also regulate greenhouse gas emissions by raising the standards set by the EPA, most notably California, to further counteract emissions and pollution.
[Last updated in January of 2022 by the Wex Definitions Team]