How fast and strong may be global warming? On this question, taking the work of paleoclimatic data, tried to answer James Hansen and Makiko Sato of the Institute for Space Studies. NASA Goddard writes denis-balin.
At a press conference during a meeting of the American Geophysical Union, Mr. Hansen has criticized what to aspire to some states, that is, to limitthaw two degrees, in order to avoid a catastrophe. According to the scientist, this is the "wrong" number, redundant. For example, two degrees is enough to cause significant loss of ice sheets in Antarctica and Greenland.
The difference between the temperature in 2010 from the average of 1951-1980 years. The darker the hotter. (Data Goddard Institute for Space Studies.)
According to the researcher, in 1880 the average surface temperature has risen by 0,8? C and is growing at 0,1? C per decade. At current rates of fossil fuel carbon dioxide concentration in the atmosphere will double from pre-industrial times to the middle of this century. This means warming of several degrees.
The researchers compared the climate of the Holocene epoch of the previous "interglacial", when the glaciers in the same way and do not dominate the polar caps remained. Analysis of the sediment showed that the average global temperature during eemskogo period beginning about 130 thousand years ago and lasted for about 15 thousand years, was less than 1? C higher than today. If today's temperature will rise by 2? C compared to pre-industrial levels, we will exceed eemsky period, and then the sea level was 4-6 meters higher than the present.
This suggests that the climate is more sensitive to temperature than it can be concluded on the basis of modern observations and computer modeling. Mr. Hansen believes that a warming of 2? C makes the Earth more like the Pliocene, when sea level was 25 meters higher than today. Scientist equals one degree increase in temperature to sea level rise by as much as 20 m However, this increase will occur for centuries — is melting slowly.
The expert also noted that the decay of the ice cover is not a linear process. This nonlinearity can be observed today: Antarctica vulnerabilities (eg, Pine Island Glacier accelerated twice every ten years) are losing ice faster than other areas.