Thursday, April 30, 2009

WHAT A WORST CASE CLIMATE SCENARIO MIGHT LOOK LIKE

Doyle Rice, USA Today - Professor Stephen Schneider of Stanford University . . . in an opinion piece in this week's journal Nature, [looks] at the absolute "worst-case" climate-change scenario, based on an atmosphere with 1,000 parts of carbon dioxide per million by the year 2100. (Current levels are about 380 ppm.) . . .

Under this scary scenario, the Earth's average temperature would likely skyrocket by as much as 11 degrees over the next 90 years. Some of the most notable effects would be: Many unique or rare systems would probably be lost, including Arctic sea ice, mountaintop glaciers, most threatened and endangered species, coral-reef communities, and many high-latitude and high-altitude indigenous human cultures.

- Extinction of some half of known plant and animal species on Earth would become much more likely.

- A sea-level rise of up to 10 meters after many centuries from the melting of the Greenland and West Antarctic ice sheets would be possible.

"People would be vulnerable in other ways too," writes Schneider. "Asian mega-delta cities would face rising sea levels and rapidly intensifying tropical cyclones, creating hundreds of millions of refugees; valuable infrastructure such as the London or New York underground systems could be damaged or lost; the elderly would be at risk from unprecedented heat waves; and children, who are especially vulnerable to malnutrition in poor areas, would face food shortages.". . .

He does admit that the likelihood of this worst-case scenario is small, on the order of about 5-10%.