Earth threatens climate collapse

IPCC: Man-made climate change already in full swing

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The earth is threatened by the end of this century, a dramatic climatic warming by up to 6.4 degrees Celsius. The sea level could also increase by up to 58 centimeters and flood many coastal areas. Around the Mediterranean Sea and in other areas of the subtropics and tropics probably less and less rain - devastating thorns would result. These are some of the darkest predictions of the 4th UN report of the Intergovernmental Panel on Climate Chance (IPCC) presented today in Paris.

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The report also shows that the Earth has been warming by more than 0.7 degrees in recent decades. If left unchecked, the climate could continue to warm by 0.2 degrees per decade over the next few decades. Eleven of the past twelve years have been the warmest since records began.

Offender: human

The IPCC report, which involved hundreds of climate scientists worldwide, has also identified a specific global warming leader: human beings. "The present report should dispel any doubts that we humans are the ones who over-ride the climate screw. Consequently, it is also in our hands to resolutely correct this dangerous development by reducing greenhouse gas emissions, "said Hans Joachim Schellnhuber, Director of the Potsdam Institute for Climate Impact Research (PIK) and Chief Adviser to the German Government on Climate Issues.

On the question of how the climate scenarios of the IPCC are to be assessed, Schellnhuber said: "The perpetrator is now convicted, but the 'penalty' is still open". Because there are still considerable uncertainties in important environmental factors such as precipitation development and sea level. display

Carbon dioxide content of the atmosphere reaches record levels

According to the IPCC, the increase in carbon dioxide levels in the air since 1750 has been responsible for the global warming up to now by 35 percent from 280 ppm to 379 ppm in 2005. This is the highest value in the last 650, 000 years. According to the IPCC, 78 percent of the increase is attributable to the use of fossil fuels and 22 percent to land-use changes such as clearing.

The consequences of climate change are already dramatic, according to the scientists:

- The frequency of heavy rainfall has increased.

- The snow-covered area has decreased by about five percent since 1980.

- Global glaciers are shrinking and currently contribute 0.8 mm per year to sea-level rise.

- Since 1978, sea ice in the Arctic has dropped by an annual average by 8% and by 22% in the summer. There is no decline in the Antarctic.

- The ice sheets in Greenland and the Antarctic are currently losing mass due to melting and glacial erosion, contributing 0.4 mm per year to sea-level rise.

- The oceans have become warmer globally, to depths of 3, 000 meters. This warming has contributed to sea level rise.

Sea level rise worries

A study published by PIK scientist Stefan Rahmstorf at the same time as the IPCC report shows that the observed increase in temperatures from 1990 to 2006 was in the upper range of what had been predicted in the last IPCC report. But the climate expert is particularly worried about the unexpectedly rapid rise in sea level.

"Satellite data show that global sea levels have increased by more than four centimeters since 1993, faster than in the calculations of the climate models." Rahmstorf warned against too fast conclusions: "Whether this observed trend continues in the future, can be based on the has yet to estimate new data. "The study, which also involved researchers from Australia, France, the United Kingdom and the United States in addition to Rahmstorf, has just been published in the online issue of Science.

Gloomy future

For the future, the model calculations of the IPCC scientists predict even worse. Using supercomputers, they have calculated different scenarios - depending on how global greenhouse gas emissions develop in the future. In the best case scenario, researchers expect global global warming of 1.0 to 2.7 C by the end of the 21st century. The highest scenario even predicts a temperature increase of 2.4 to 6.4 C over the next 100 years. According to the IPCC report, the largest warming will take place, especially in the high northern latitudes. And even with an immediate end to all greenhouse gas emissions, the inertia of the climate system would cause a further temperature increase of up to about 0.6 C.

With regard to sea-level rise, the projections up to 2100 are also clear: 19 to 37 centimeters are in the lowest and 26 to 58 centimeters in the highest scenario. Even after the emissions have completely ceased, sea levels will continue to rise over many centuries due to further warming of the deep ocean. However, according to the scientists, there is considerable uncertainty regarding the further development of the Greenlandic and Antarctic ice sheets, and a higher contribution to the future increase can not be ruled out.

In addition, the model results suggest that a permanent warming above 3 C over millennia could lead to a complete melting of the Greenland ice cap This would correspond to a sea level rise of seven meters.

Fast action necessary

The IPCC report shows that very consistent action is needed to ensure that global warming does not rise more than two degrees above pre-industrial levels. "Managing climate change requires intelligent technology change on a sound scientific basis, and to keep climate change within acceptable limits, we need to conduct intensive research and ensure the rapid spread of climate-friendly technologies, " commented Federal Research Minister Annette Schavan presented the IPCC results at the presentation of the report in Berlin.

And further: "For this purpose, the Federal Ministry of Research will provide 255 million euros over the next three years. Among other things, we are promoting the expansion of the German Climate Computing Center - alone 35 million euros have been earmarked for this. "The Federal Minister of Research will shortly be launching an action program on climate change that focuses on the needs of people and society provides.

(Potsdam Institute for Climate Impact Research (PIK) / BMBF / AWI, 02.02.2007 - DLO)