deforestation, the clearing or thinning of forests by humans. Deforestation represents one of the largest issues in global land use. Estimates of deforestation traditionally are based on the area of forest cleared for human use, including removal of the trees for wood products and for croplands and grazing lands.
As greenhouse gas emissions blanket the Earth, they trap the sun’s heat. This leads to global warming and climate change. The world is now warming faster than at any point in recorded history.
Generating electricity and heat by burning fossil fuels such as coal, oil, and natural gas causes a large chunk of global emissions. Most of the electricity is still produced from fossil fuels; only about a quarter comes from wind, solar, and other renewable sources.
Manufacturing and industry produce emissions, mostly from burning fossil fuels to produce energy for making things like cement, iron, steel, electronics, plastics, clothes, and other goods. Mining and other industrial processes also release gases.
Cutting down forests to create farms or pastures, or for other reasons, causes emissions because when trees are cut, they release the carbon they have been storing. Since forests absorb carbon dioxide, destroying them also limits nature’s ability to keep emissions out of the atmosphere.