Earth-solar cycle spurs greenhouse gases -
05-24-2006, 08:00 AM
Greenhouse gases are known to spur global warming, but scientists said on Monday that global warming in turn spurs greenhouse gas emissions -- which means Earth could get hotter faster than climate models predict.
Two scientific teams, one in Europe and another in California, reached the same basic conclusion: when Earth has warmed up in the past, due to the sun's natural cycles, more greenhouse gases have been spewed into the atmosphere.
As greenhouse gas levels rose, so did Earth's temperature, the scientists reported.
Earth has not endlessly warmed up, though, because these natural solar cycles ended, letting the planet cool down and prompting a corresponding drop in greenhouse gas emissions, the scientists reported.
But these previous periods of heating and cooling were not influenced by the burning of fossil fuels, and the current resulting trend toward higher global average temperatures, according to Margaret Torn of Lawrence Berkeley National Laboratory.
"It means the warming is happening faster, each decade is actually warming faster than it would have," Torn said in a telephone interview. "It's the pace of change that will be one of the big problems. It's how humans adapt and the cost that will depend on the rate of change of climate."