Climate Change

TCS has a good article about climate change. (Not something Gore would want to read; he wants reality to follow his bidding...that comes from his education...influenced by John Dewey...influenced by Immanuel Kant, who said 'reality is a social construct.')

Snowfall here in the Northeast and across much of the Hemisphere relate to decadal scale cycles in the Atlantic and Arctic. Two atmospheric oscillations which generally operate in tandem -- the North Atlantic and Arctic Oscillations -- have significant control over the weather pattern including storm tracks and temperatures in both Europe and the eastern United States.

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Over the last decade the behavior of the NAO/AO has been similar to the 1930s and 1940s (Taylor, 2005) when the NAO moved from a positive to increasingly negative state. Interestingly, that was the last time the Polar Regions were this warm and the summer polar ice this thin and reduced in coverage (Polyakov et al, 2004). Unlike Antarctica where the ice sits on land, in the arctic it is floating on water and the water from one ocean (the Atlantic) can readily flow beneath the ice and if unusually warm, melt more of the ice from beneath.

As George Taylor summarized on this site in his story "Arctic Sea Ice -- Is It Disappearing?"

"A number of researchers have suggested that inflows of Atlantic water into the Arctic profoundly affect temperatures and sea ice trends in the latter ocean. Polyakov, et al (2004) are among these. The first sentence of their paper states 'Exchanges between the Arctic and North Atlantic Ocean have a profound influence on the circulation and thermodynamics of each basin.' The authors attributed most of the variability to multidecadal variations on time scales of 50-80 years, with warm periods in the 1930s-40s and in recent decades, and cool periods in the 1960s-70s and early in the twentieth century. These are associated with changes in ice extent and thickness (as well as air and sea temperature and ocean salinity). The most likely causative factor involves changes in atmospheric circulation, including but not limited to the Arctic Oscillation"

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By the way, this latest mode of the North Atlantic Oscillation is the one that Dr .William Gray talks about that favored the sudden increase in Atlantic hurricane activity since the middle 1990s. Last year, Atlantic temperatures were the warmest on record, helping contribute to the record 28 named storms.

Snowfall has been on the increase in parts of the United States and the world to record proportions in recent years even as summer snow and ice levels reach multi-decadal lows. The changes relate to natural cyclical changes in the Atlantic Ocean and atmosphere that favor both more tropical activity in summer and more snowfall in winters.

The whole article is worth reading. It has some good graphics to help grasp the NAO/AO phenomenon.

Environment Posted by Cyrano at June 6, 2006 10:53 AM