Methane (CH 4): Methane is emitted during the production and transport of coal, natural gas, and oil.Carbon dioxide is removed from the atmosphere (or 'sequestered') when it is absorbed by plants as part of the biological carbon cycle. Carbon dioxide (CO 2): Carbon dioxide enters the atmosphere through burning fossil fuels (coal, natural gas, and oil), solid waste, trees and other biological materials, and also as a result of certain chemical reactions (e.g., cement production).
For more information on the other climate forcers, such as black carbon, please visit the Climate Change Indicators: Climate Forcing page. This section provides information on emissions and removals of the main greenhouse gases to and from the atmosphere. Gases that trap heat in the atmosphere are called greenhouse gases. Greenhouse Gas Emissions and Sinks: 1990–2021. This net sink is not shown in the above diagram. All emission estimates from the Inventory of U.S. Percentages may not add up to 100% due to independent rounding. Land Use, Land-Use Change, and Forestry in the United States is a net sink and offsets 12% of these greenhouse gas emissions. Emissions in 2021 = 6,340 Million Metric Tons of CO₂ equivalent (excludes land sector).
