Global warming has many explanation. Main it is considered increase of concentration of “hotbed” gases, namely the gases promoting occurrence of “hotbed effect”- characteristic of an atmosphere to pass solar radiation ,but to hold terrestrial radiation and by that to promote accumulations of heat by the Earth. One of the basic hotbed gases is carbonic gas which achieve in an atmosphere as a result of process of combustion. There are also other factors: negative influence is submitted by way of cutting down of woods, extraction of minerals, etc.
National Research Council specifies, that noticeable influence on a climate is rendered by changes during use terrestrial goods . For example, it influences at quantity of an solar radiation absorbed and reflected by terrestrial surface. Besides there is also other effect. For example, one of ” hotbed gases ” is methane ,which two thirds of emissions are caused by activity of the human. Methane is produced during cultivation of rice, cultivation of large domestic animals, a coal mining and so forth As a result, nowadays concentration of methane in an atmosphere is record-breaking high, and the level of concentration stably raises since the last half of 20th century.
By estimations of the National Climatic Data Center, for last century the maintenance of carbonic gas in a world atmosphere has grown from 300 up to 380 parts on 1 million, and the average temperature of a terrestrial surface has grown approximately on 0.7 degrees on a scale of Celsius. Last decade of 20th century became the warmest during making of measurements of standard temperature (from the middle of 19th century). 1990th years were included into count as the warmest 15 years, six years of this decade were the “hottest” years of century. In turn, company Accu-Weather ,which is engaged in commercial use of meteorological data, approves, that in 20th century the average world temperature has risen on 0.45 degrees on a scale of Celsius.
Thus , the temperature most quickly raises in Arctic regions (Siberia, Alaska, Canada). By estimations of the international group of scientists (refers to Arctic Climate Impact Assessment), near to North Pole temperatures grew twice as much quickly, than, as a whole ,on a planet. It is supposed, that by 2040, or even earlier, the Arctic ocean can remain without an ice. In Northern hemisphere the spring (within temperature, not within calendar sense) appears on one week earlier, and winter - a week later, than on previously century.
In the world the quantity and the sizes of mountain glaciers and snows decreases. For example, according to magazine National Geographic, in territory of hilly state of Montana (USA) in 1910 were 150 glaciers totaled, and in 2007 remains only 27.
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