Climate Change
See also: Climate change, Global warming, Temperature record, and Attribution of recent climate changeClimate change is the variation in global or regional climates over time. It reflects changes in the variability or average state of the atmosphere over time scales ranging from decades to millions of years. These changes can be caused by processes internal to the Earth, external forces (e.g. variations in sunlight intensity) or, more recently, human activities.
In recent usage, especially in the context of environmental policy, the term "climate change" often refers only to changes in modern climate, including the rise in average surface temperature known as global warming. In some cases, the term is also used with a presumption of human causation, as in the United Nations Framework Convention on Climate Change (UNFCCC). The UNFCCC uses "climate variability" for non-human caused variations.
Earth has undergone periodic climate shifts in the past, including four major ice ages. These consisting of glacial periods where conditions are colder than normal, separated by interglacial periods. The accumulation of snow and ice during a glacial period increases the surface albedo, reflecting more of the Sun's energy into space and maintaining a lower atmospheric temperature. Increases in greenhouse gases, such as by volcanic activity, can increase the global temperature and produce an interglacial. Suggested causes of ice age periods include the positions of the continents, variations in the Earth's orbit, changes in the solar output, and volcanism.
Read more about this topic: Climate
Famous quotes containing the words climate and/or change:
“Is not their climate foggy, raw, and dull,
On whom, as in despite, the sun looks pale,
Killing their fruit with frowns?”
—William Shakespeare (1564–1616)
““But there’s always been rich and poor, and that’s all there is to it. And us two won’t change it, either.”
The carpenter calmly puffs away: “Only the ones that likes it ought to be poor. Let the others have a try at it first. I ain’t got no liking for it. A fellow gets tired of it after a while.””
—Alfred Döblin (1878–1957)