Tuesday, January 27, 2009

Global Warming Irreversible, Study Says


Not only is global warming most likely inevitable, it is also not easily reversed, says a new study. The press release is here, but I could not locate the actual study at the website listed. Full text of study here.

If CO2 is allowed to peak at 450-600 parts per million, the results would include persistent decreases in dry-season rainfall that are comparable to the 1930s North American Dust Bowl in zones including southern Europe, northern Africa, southwestern North America, southern Africa and western Australia.

The study notes that decreases in rainfall that last not just for a few decades but over centuries are expected to have a range of impacts that differ by region. Such regional impacts include decreasing human water supplies, increased fire frequency, ecosystem change and expanded deserts. Dry-season wheat and maize agriculture in regions of rain-fed farming, such as Africa, would also be affected.

...

The scientists emphasize that increases in CO2 that occur in this century “lock in” sea level rise that would slowly follow in the next 1,000 years. Considering just the expansion of warming ocean waters—without melting glaciers and polar ice sheets—the authors find that the irreversible global average sea level rise by the year 3000 would be at least 1.3–3.2 feet (0.4–1.0 meter) if CO2 peaks at 600 parts per million, and double that amount if CO2 peaks at 1,000 parts per million.


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