 |
Previous Result
Next Result
Back to Search Results
Adjacent entries
Related subjects
|
|
Global Warming
An increase in the average temperature of the Earth, primarily because of a rise in concentration of various greenhouse gases in the atmosphere. Although significant warming episodes have occurred in the past, particularly accompanying interglacial phases, the term is generally used nowadays for the anthropogenic effect upon climate. The principal source of concern is the great increase in carbon dioxide released by the burning of fossil fuels. Various other gases also contribute, and all these substances are subject to the Kyoto Protocol. Current results suggest that warming is occurring at c.1.5 ºC per century.
Warming is primarily confined to the troposphere and is balanced by a corresponding cooling of the stratosphere and mesosphere. Recent results indicate that this upper-atmospheric cooling is causing the altitude of the ionosphere to decrease. Although the amount of warming at the surface is subject to some debate, its effects are apparently visible in the melting of glaciers, and a general rise in sea level. Although modelling of global warming is incomplete, general circulation models suggest that there will be a significant latitudinal variations, particularly in increased cloudiness, frequency of severe storms, and changes in precipitation.
|
|