Potsdam Institute - As Warming Grows, So Do Odds Of Colder N. Hemisphere Winters - Reuters

[hatrack]

Climate change could lead to colder winters in northern regions, according to a study by the Potsdam Institute for Climate Impact Research on Tuesday.

Vladimir Petoukhov, lead author of the study, said a shrinking of sea ice in the eastern Arctic causes some regional warming of lower air levels and may lead to anomalies in atmospheric airstreams, triggering an overall cooling of the northern continents. "These anomalies could triple the probability of cold winter extremes in Europe and northern Asia," he said. "Recent severe winters like last year's or the one of 2005/06 do not conflict with the global warming picture but rather supplement it."

Petoukhov, whose study is entitled "A link between reduced Barents-Kara sea ice and cold winter extremes over northern continents," said in a statement a warming of the air over the Barents-Kara Sea appeared to bring cold winter winds to Europe.

"This is not what one would expect," Petoukhov said. "Whoever thinks that the shrinking of some far away sea ice won't bother him could be wrong."

EDIT

http://planetark.org/enviro-news/item/60251

[knitter4democracy]

1. Is it like when the Lakes don't freeze over all the way and there's more snow?

That's where our lake effect comes from, so I could see a lot more snow if there's more water surface for the air to pick moisture up from.

[Celefin]

2. Here's the abstract of the study

The recent overall Northern Hemisphere warming was accompanied by several severe
northern continental winters, as for example, extremely cold winter 2005–2006 in Europe
and northern Asia. Here we show that anomalous decrease of wintertime sea ice
concentration in the Barents‐Kara (B‐K) seas could bring about extreme cold events like
winter 2005–2006. Our simulations with the ECHAM5 general circulation model
demonstrate that lower‐troposphere heating over the B‐K seas in the Eastern Arctic
caused by the sea ice reduction may result in strong anticyclonic anomaly over the
Polar Ocean and anomalous easterly advection over northern continents. This causes a
continental‐scale winter cooling reaching −1.5°C, with more than 3 times increased
probability of cold winter extremes over large areas including Europe. Our results imply
that several recent severe winters do not conflict the global warming picture but rather
supplement it, being in qualitative agreement with the simulated large‐scale atmospheric
circulation realignment. Furthermore, our results suggest that high‐latitude atmospheric
circulation response to the B‐K sea ice decrease is highly nonlinear and characterized
by transition from anomalous cyclonic circulation to anticyclonic one and then back again
to cyclonic type of circulation as the B‐K sea ice concentration gradually reduces from
100% to ice free conditions. We present a conceptual model that may explain the nonlinear
local atmospheric response in the B‐K seas region by counter play between convection
over the surface heat source and baroclinic effect due to modified temperature gradients
in the vicinity of the heating area.
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So much for for the people shouting about all the snow the saw 'looking out of their windows' last year and how it proved the earth was cooling.
While the arctic had the warmest winter ever.
The big picture seems soooo difficult to grasp. *sigh*

[Celefin]

3. Link to PIK Potsdam press release

http://www.pik-potsdam.de/news/press-releases/global-warming-could-cool-down-temperatures-in-winter

[NickB79]

4. I wonder if that applies to N. America too?

One of the few positive aspects of global warming is that it could allow me to grow some otherwise non-hardy species of fruit trees and shrubs here in Minnesota. If global warming gives us hotter, more humid summers AND colder winters, that just sucks.