The result is that the globe has heated up by about one degree Fahrenheit over the past century—and it has heated up more intensely over the past two decades. Already, people have increased the amount of CO2, the chief global warming pollutant, in the atmosphere to 31 percent above pre-industrial levels. There is more CO2 in the atmosphere now than at any time in the last 650,000 years. Studies of the Earth’s climate history show that even small changes in CO2 levels generally have come with significant shifts in the global average temperature.
-The basics of global warming
-Updated last january 9,2009
-Enviromental Defense Foundation
Earth's water cycle has been pushed to its limit. The amount of water evaporating off the land and into the atmosphere hit a maximum 12 years ago and is now in decline, new calculations show.
Martin Jung of the Max Planck Institute for Biogeochemistry in Jena, Germany, and colleagues calculated trends in evapotranspiration – the amount of water vapour that entered the atmosphere – between 1982 and 2008. This moisture is either evaporated off the land by the sun's heat or released by plants.
They found that evapotranspiration rose steadily until 1998, as would be expected in a warming global climate. But the trend reversed in 1998, and the amount of moisture being cycled into the atmosphere began to drop.
Team member Steven Running of the University of Montana in Missoula says that in some regions, rising temperatures have sucked all the available water out of the ground. Though that moisture returns to the ground as rain, most of it falls elsewhere, leaving dry regions like Australia parched.
- Water Cycle Goes Bust As The World Gets Warmer
-October 10, 2010
-Michael Marshall
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