I found these articles on DU:
http://www.washingtonpost.com/wp-dyn/content/article/2005/09/15/AR2005091502234.htmlHurricane Severity Increasing Thanks To Water Temps - ScienceA new study concludes that rising sea temperatures have been accompanied by a significant global increase in the most destructive hurricanes, adding fuel to an international debate over whether global warming contributed to the devastation wrought by Hurricane Katrina. The study, published today in the journal Science, is the second in six weeks to draw this conclusion, but other climatologists dispute the findings and argue that a recent spate of severe storms reflects nothing more than normal weather variability.
Katrina's destructiveness has given a sharp new edge to the ongoing debate over whether the United States should do more to curb greenhouse gas emissions linked to global warming. Domestic and European critics have pointed to Katrina as a reason to take action, while skeptics say climate activists are capitalizing on a national disaster to further their own agenda. According to data gathered by researchers at the School of Earth and Atmospheric Sciences at Georgia Tech and the National Center for Atmospheric Research, the number of major Category 4 and 5 hurricanes worldwide has nearly doubled over the past 35 years, even though the total number of hurricanes, including weaker ones, has dropped since the 1990s. Katrina was a Category 4 storm when it made landfall.
Using satellite data, the four researchers found that the average number of Category 4 and 5 hurricanes -- those with winds of 131 mph or higher -- rose from 10 a year in the 1970s to 18 a year since 1990. Average tropical sea surface temperatures have increased as much as 1 degree Fahrenheit during the same period, after remaining stable between 1900 and the mid-1960s.
Georgia Tech atmospheric scientist Judith A. Curry -- co-author of the study with colleagues Peter J. Webster and Hai-Ru Chang, and NCAR's Greg J. Holland -- said in an interview that their survey, coupled with computer models and scientists' understanding of how hurricanes work, has given the researchers a better sense of how rising sea temperatures are linked to more-intense storms. "There is increasing confidence, as the result of our study, that there's some level of greenhouse warming in what we're seeing," Curry said. "Is it the whole story? We don't know."
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http://news.independent.co.uk/world/science_technology/article312997.eceGlobal warming 'past the point of no return'By Steve Connor, Science Editor
Published: 16 September 2005
A record loss of sea ice in the Arctic this summer has convinced scientists that the northern hemisphere may have crossed a critical threshold beyond which the climate may never recover. Scientists fear that the Arctic has now entered an irreversible phase of warming which will accelerate the loss of the polar sea ice that has helped to keep the climate stable for thousands of years.
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Experts believe that such a loss of Arctic sea ice in summer has not occurred in hundreds and possibly thousands of years. It is the fourth year in a row that the sea ice in August has fallen below the monthly downward trend - a clear sign that melting has accelerated.
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Such lows have normally been followed the next year by a rebound to more normal levels, but this did not occur in the summers of either 2003 or 2004. This summer has been even worse. The surface area covered by sea ice was at a record monthly minimum for each of the summer months - June, July and now August.
Scientists analysing the latest satellite data for September - the traditional minimum extent for each summer - are preparing to announce a significant shift in the stability of the Arctic sea ice, the northern hemisphere's major "heat sink" that moderates climatic extremes.
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Sea ice reflects up to 80 per cent of sunlight hitting it but this "albedo effect" is mostly lost when the sea is uncovered. "We've exposed all this dark ocean to the sun's heat so that the overall heat content increases," he explained.
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Sea ice keeps a cap on frigid water, keeping it cold and protecting it from heating up. Losing the sea ice of the Arctic is likely to have major repercussions for the climate, he said. "There could be dramatic changes to the climate of the northern region due to the creation of a vast expanse of open water where there was once effectively land,"
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