A Daily news digest by Jasper van Santen

Clouds’ Effect on Climate Change Is Last Bastion for Dissenters – NYTimes.com

In News on May 1, 2012 at 10:05

Clouds’ Effect on Climate Change Is Last Bastion for Dissenters 

For decades, a small group of scientific dissenters has been trying to shoot holes in the prevailing science of climate change, offering one reason after another why the outlook simply must be wrong.

Over time, nearly every one of their arguments has been knocked down by accumulating evidence, and polls say 97 percent of working climate scientists now see global warming as a serious risk.

Yet in recent years, the climate change skeptics have seized on one last argument that cannot be so readily dismissed. Their theory is that clouds will save us.

They acknowledge that the human release of greenhouse gases will cause the planet to warm. But they assert that clouds — which can either warm or cool the earth, depending on the type and location — will shift in such a way as to counter much of the expected temperature rise and preserve the equable climate on which civilization depends.

Their theory exploits the greatest remaining mystery in climate science, the difficulty that researchers have had in predicting how clouds will change. The scientific majority believes that clouds will most likely have a neutral effect or will even amplify the warming, perhaps strongly, but the lack of unambiguous proof has left room for dissent.

“Clouds really are the biggest uncertainty,” said Andrew E. Dessler, a climate researcher at Texas A&M. “If you listen to the credible climate skeptics, they’ve really pushed all their chips onto clouds.”

Richard S. Lindzen, a professor of meteorology at the Massachusetts Institute of Technology, is the leading proponent of the view that clouds will save the day. His stature in the field — he has been making seminal contributions to climate science since the 1960s — has amplified his influence.

Dr. Lindzen says the earth is not especially sensitive to greenhouse gases because clouds will react to counter them, and he believes he has identified a specific mechanism. On a warming planet, he says, less coverage by high clouds in the tropics will allow more heat to escape to space, countering the temperature increase.

His idea has drawn withering criticism from other scientists, who cite errors in his papers and say proof is lacking. Enough evidence is already in hand, they say, to rule out the powerful cooling effect from clouds that would be needed to offset the increase of greenhouse gases.

 

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s