IPCC warning on warming

[Karlin]

We are finally getting SOME of the reports on the worst effects of global warming, warning that we needed to hear 10 years ago to make us get off the couch and do something about our fossil fuel emissions.

The recent IPCC report from the United Nations does not really give us the worst case scenarios, just the scenarios that those scientists could agree on. They did not quite admit that a temperature rise of over 6degrees celcius might occur by 2100, but this Common Dreams articles does find some referance to it in that IPCC report:

"The Hellish Vision of Life on a Hotter Planet"

http://www.commondreams.org/views07/0203-28.htm

Buried within the newly released IPCC report is an apocalyptic warning: if greenhouse gas emissions continue to rise at current rates, global warming by the end of the century could total 6.4C.
It would cause a mass extinction of almost all life and probably reduce humanity to a few struggling groups of embattled survivors clinging to life near the poles.

"Global Warming: The Final Warning
- Carbon Dioxide Rate is at Highest Level for 650,000 Years"

http://www.commondreams.org/headlines07/0203-03.htm
Quoting the IPCC report:

Concentrations of carbon dioxide in the atmosphere are at their highest levels for at least 650,000 years and this rise began with the birth of the Industrial Revolution 250 years ago, according to the Intergovernmental Panel on Climate Change (IPCC).
Carbon dioxide is the principal greenhouse gas responsible for global warming and, in 2005, concentrations stood at 379 parts per million (ppm). This compares to a pre-industrial level of 278 ppm, and a range over the previous 650,000 years of between 180 and 300 ppm, the report says.

And, they are finally referring to "cascade effects" where warming creates conditions for more warming, now they are calling it "positive feedback" [because it sounds better?]:

IPCC's summary says: "Warming tends to reduce land and ocean uptake of atmospheric carbon dioxide, increasing the fraction of anthropogenic [man-made] emissions that remain in the atmosphere."

This is just one of several "positive feedbacks" that could quickly accelerate the rate of global warming over the coming century. One isa warmer world is causing more evaporation from the oceans and a rise in water vapour - a powerful greenhouse gas - in the lower atmosphere. Another is sea ice and snow cover is shrinking at the poles and on mountains, leading to a further increase in local temperatures.

So it will start to mulitply exponentially, it will warp in on itself, it will thunder down upon our heads with astonishing suddeness - whatever you call it, global warming does create more global warming, and we can do something about it. Well, we could have 10 years ago, now it is too late to avoid the most of it because the "postiive feedback" has begun allready.
The longer we wait, the more it will cost to reverse it was fully understood 10 yars ago...and they are still not telling us the worst case scenarios...