Top climate story of 2008: Arctic sea ice loss

cnc66 · Jan 13, 2009

Dr. Masters over at weather underground has posted a blog about artic sea ice.

Top climate story of 2008: Arctic sea ice loss

Dr.Jeff Masters said:

The top climate story of 2008, as it was in 2007, was the extraordinary summertime sea ice retreat in the Arctic. For the second consecutive year, we experienced the opening of the fabled Northwest Passage through the Canadian Arctic waters. Explorers have been attempting to sail the Northwest Passage since 1497, and 2007 and 2008 are the only known years the passage has been ice-free. In addition, 2008 saw the simultaneous opening of the Northeast Passage along the coast of Russia. This meant that for the first time in recorded history, the Arctic ice cap was an island--one could completely circumnavigate the Arctic Ocean in ice-free waters. Although the summer ice extent in 2008 finished 9% higher than 2007's record minimum, it was still an extraordinary 34% below average, according to the National Snow and Ice Data Center. Furthermore, the ice was thinner at the September 2008 minimum compared to 2007, so the total ice volume (thickness times area) was probably at its lowest point in recorded history in 2008.
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Heck of a statement. There are some graphs and such to peruse, with many links to more info.

Dr. Masters said:

The future of arctic sea ice
Climate models have done a poor job predicting the recent record loss of arctic sea ice (Figure 3). None of the models used to formulate the official word on climate, the 2007 United Nations IPCC report, foresaw the shocking drop of 2007-2008.

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The year 1941 still ranks as the warmest year in the Arctic, though 2007 was virtually tied with it. However, the warmth of the 1930s and 1940s was different than the current warming, and was caused by the Siberian High moving unusually far east over Europe, driving warm, southerly winds over Greenland. The warmth in the past decade, in contrast, is associated with a warming of the entire planet, and is not due to an unusual pressure pattern driving warm air into the region.
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more graphs and pictures about this

The impact on sea level rise
The loss of arctic sea ice will have little impact on sea level rise over the next few decades. Since the ice is already floating in the ocean, melting it does not change sea level much--just like when ice melting in a glass of water will not change the level of liquid in the glass. In the case of sea ice, there is a slight sea level rise, since the fresh melt water is less dense than the salty ocean water it displaces. If all the world's sea ice melted, it would raise global sea level by only 4 mm. This is a tiny figure compared to the 20 feet of sea level rise that would occur from complete melting of the Greenland ice sheet--which is on land.

The impact on melting of the Greenland Ice Sheet
The big concern with arctic sea ice melt is the warmer temperatures it will bring to the Arctic, which will bring about an accelerated melting of the Greenland Ice Sheet.

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The IPCC estimates were also made before the shocking and unexpected loss of arctic sea ice of the past two summers. In light of these factors, a large number of climate scientists now believe the IPCC estimates of sea level rise this century are much too low. The most recent major paper on sea level rise, published this month by Grinsted et al., concluded that there was a "low probability" that sea level rise would be in the range forecast by the IPCC, and predicted a 0.9 - 1.3 meter (3 - 4.3 feet) rise by 2100. Pfeffer et al. last month concluded that a "most likely" range of sea level rise by 2100 is 2.6 - 6.6 feet (0.8 - 2.0 meters). Their estimates came from a detailed analysis of the processes the IPCC said were understood too poorly to model--the ice flow dynamics of glaciers in Greenland and Antarctica. The authors caution that "substantial uncertainties" exist in their estimates, and that the cost of building higher levees to protect against sea level rise is not trivial. Other recent estimates of sea level rise include 1.6 - 4.6 feet (0.5 - 1.4 meters) by Rahhmstorf (2007).

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What would 3 feet of sea level rise mean?
Rising sea levels will lead to permanent and intermittent flooding in low-lying coastal areas across the world. A global sea level rise of .9 meters (3 feet) would affect 100 million people worldwide, mostly in Asia. The impact of hurricane storm surges will significantly increase as a result of sea level rise. Given a 3 foot rise in sea level, Hurricane Ike's storm surge would have overwhelmed the levees in Port Arthur, Texas, flooding the city and its important oil refineries. Galveston's sea wall would have been overtopped and possibly destroyed, allowing destruction of large portions of Galveston. Levees in New Orleans would have been overtopped, resulting in widespread flooding there, as well. I'll have a full analysis of who's at risk, and what the risks are, in a series of forthcoming blog posts this year.
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Scary stuff.. but as I keep harping, a great opportinity for forward thinking investors and inventors.

jdang307 · Jan 14, 2009

Although the summer ice extent in 2008 finished 9% higher than 2007's record minimum ...
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That's what I read. At least.

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