M.I.T. verdubbelt 2095 temperatuurstijging tot 5.6°C, bij 866 ppm

By Joe Romm, Climate Progress, May 20, 2009

The new projections [for business as usual] are considerably warmer than the 2003 projections, e.g., the median surface warming in 2091 to 2100 is 5.2°C compared to 2.4°C in the earlier study.

(...) Their median projection for the atmospheric concentration of carbon dioxide in 2095 is a jaw-dropping 866 ppm.

(...) Speaking of feedbacks, the model shows staggering warming near the poles (see 'What exactly is polar amplification and why does it matter?'): Median arctic warming - north of 70° latitude - is 11°C (20°F) from 1981-2000 levels! [see graph above]. How could Greenland’s ice sheet possibly survive that?

For the no policy scenario, the researchers concluded that there is now a nine percent chance (...) that the global average surface temperature would increase by more than 7°C (12.6°F) by the end of this century, compared with only a less than one percent chance (...) that warming would be limited to below 3°C (5.4°F).

[Note by me, Gaia: remember: 2°C is considered to be the 'danger limit':
We feel compelled to note that even a "moderate" warming of 2°C stands a strong chance of provoking drought and storm responses that could challenge civilized society, leading potentially to the conflict and suffering that go with failed states and mass migrations. Global warming of 2°C would leave the Earth warmer than it has been in millions of years, a disruption of climate conditions that have been stable for longer than the history of human agriculture. Given the drought that already afflicts Australia, the crumbling of the sea ice in the Arctic, and the increasing storm damage after only 0.8°C of warming so far, calling 2°C a danger limit seems to us pretty cavalier.
Also, there are dangers to CO₂ emission other than the peak, such as the long tail of the CO₂ perturbation which will dominate the ultimate sea level response
, and the acidification of the ocean. A building may be safe from earthquakes but if it is susceptible to fires it is still considered unsafe.

Zie ook:

Global warming of 7°C 'could kill billions this century'
By Louise Gray, Telegraph.co.uk, May 20, 2009

Global warming could be twice as bad as forecast
Reuters, May 19, 2009