Sat Dec 12th, 2009 at 01:15:29 PM EST
From Jeff Masters on Weather Underground.
The dramatic loss of Arctic sea ice in recent years has created a fundamental new change in the atmospheric circulation in the Northern Hemisphere that has sped up sea ice loss and is affecting fall and winter weather across most of the Northern Hemisphere, according to several recent studies. Arctic sea ice loss peaks in September and October, exposing a large area of open water that heats the air above it. This extra heat has helped drive September - November air temperatures in the Arctic to 1°C (1.8°F) or more above average over about half of the depth of the lower atmosphere (Figure 1). This deep layer of warm air has grown less dense and expanded, pushing the top of the troposphere (the lower atmosphere) higher. The result has been a decrease in the pressure gradient (the difference in pressure) between the North Pole and mid-latitudes. With not as much difference in pressure to try and equalize, the jet stream has slowed down in the Arctic, creating a major change in the atmospheric circulation for the Northern Hemisphere.
the extreme loss of Arctic sea ice since 2001 has been accompanied by a radical shift of the Arctic atmospheric circulation patterns, into a new mode they call the Arctic Rapid change Pattern. The new atmospheric circulation pattern has also been recognized by other researchers, who refer to it as the Arctic Dipole ...
The old atmospheric patterns that controlled Arctic weather--the North Atlantic Oscillation (NAO) and Arctic Oscillation (AO), which featured air flow that tended to circle the pole, now alternate with the new Arctic Dipole pattern. The Arctic Dipole pattern features anomalous high pressure on the North American side of the Arctic, and low pressure on the Eurasian side. This results in winds blowing more from south to north, increasing transport of heat into the central Arctic Ocean.
It turns out that the new Arctic circulation patterns help to intensify the Siberian High, a large semi-permanent region of surface high pressure prevalent in winter over Siberia ... resulting in colder than average temperatures from East Asia to Europe.
Low arctic ice has also been associated with drier winters in Northern Europe.
Arctic sea ice loss appears to have created a new atmospheric circulation pattern that brings more warm air in the Arctic, creating a positive feedback loop that causes even more sea ice loss. This feedback loop increases the likelihood that an ice-free Arctic in the summer will indeed come by 2030, as many Arctic experts are predicting.
We Are Here. (Somewhere)
Based on 30 years of working with dynamic, non-linear, dynamic non-linear, Chaotic dynamic non-linear, and Complex Chaotic dynamic non-linear Systems (to quote Drew, "Wheeeeeeeeeeee!") I can confidently say: I have no clue as to when Global Climate Change will become apparent to politicians, journalists, NCE economists, and the other intellectually negligible and neither does anybody else. What can be said is:
- Global Climate Change is happening
- It will happen quicker than the IPCC predicts
- Ain't Gonna Stop It
The time for halting the Change is past. Once a Complex Chaotic dynamic non-linear System moves it continues to move until it finds a stable relationship between all
it's attractors and all
4. The Effects Will Be Profound
We're talking a Global population loss of 30 to 60 percent based on the exact nature of the Change and the preparatory work done to alleviate the Change by national governments, international organizations, and NGOs.