Sunlight travels through the atmosphere mainly as ultraviolet radiation, which warms the Earth. This causes the ground to emit infrared radiation, but only a small portion of this heat escapes into space because infrared radiation is absorbed by greenhouse gases in the atmosphere. The higher the concentration of greenhouse gases, the more heat is trapped and the warmer Earth gets.

Greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons and sulfur hexafluoride. The first four gases occur naturally and are necessary to keep our planet at a comfortable temperature.

But since industrialization, atmospheric levels of greenhouse gases, especially CO2, have significantly increased as a result of human activity, particularly the burning of fossil fuels. And unlike other air pollutants, most greenhouse gases stay in the atmosphere for centuries, not just days or weeks. Virtually all climate scientists believe this contributes to global warming, which could cause unwelcome shifts in regional climates.

Studies by the Intergovernmental Panel on Climate Change show that carbon capture and storage can play an important role in stabilizing greenhouse gases in the atmosphere. Other measures include energy conservation, improvements in energy efficiency, shifting to fuels with little or no carbon such as nuclear and renewables, and reducing non-CO2 greenhouse gas emissions.