Weird Weather in a Warming World

[groovedaddy]

GIVEN the weather of late, extremes seem to have become the norm. New York City just had its hottest June-to-August stretch on record. Moscow, suffering from a once-in-a-millennium heat wave, tallied thousands of deaths, a toll that included hundreds of inebriated, overheated citizens who stumbled into rivers and lakes and didn’t come out. Pakistan is reeling from flooding that inundated close to a fifth of the country.

For decades, scientists have predicted that disastrous weather, including heat, drought and deluges, would occur with increasing frequency in a world heated by the rising concentrations of greenhouse gases. While some may be tempted to label this summer’s extremes the manifestation of our climate meddling, there’s just not a clear-cut link — yet.

Martin Hoerling, a research meteorologist who investigates extreme weather for the National Oceanic and Atmospheric Administration, calls any such impression “subjective validation.” He and other climate scientists insist there’s still no way to point to any particular meteorological calamity and firmly finger human-caused global warming, despite high confidence that such warming is already well under way.

One reason is that extreme weather, while by definition rare, is almost never truly unprecedented. Oklahoma City and Nashville had astonishing downpours this year, but a large area of Vermont was devastated by a 36-hour deluge in November 1927. The late-season tropical storm killed more than 80 people, including the state’s lieutenant governor, drowned thousands of dairy cows and destroyed 1,200 bridges.

http://www.nytimes.com/2010/09/08/opinion/08revkin.html?th&emc=th

[hedgehog]

1. On the other hand, some scientists trace global climate change

back to the discovery of agriculture. In other words, we've been changing the climate for millennia; the difference now is that we've accelerated the changes. The anomalous events on record may simply have been early indicators of what's happening.