Global Warming might lead to wetter Earth

[n2doc]

Warmer Earth might be wetter, scientists find
Keay Davidson, Chronicle Science Writer
Friday, June 1, 2007

In a report that challenges conventional wisdom, Earth might become much rainier if planetary warming continues unabated, a Santa Rosa team of experts on climate change announced today.
Over the next 100 years, global rainfall could increase by about 20 percent -- three times as fast as the rate projected previously by global-warming scientists -- if greenhouse gases in the atmosphere continue unabated, said physicist Frank Wentz and colleagues at Remote Sensing Systems in Santa Rosa. Their report appears in today's issue of Science Express, an online publication associated with Science magazine.
Their study is not precise enough to forecast how increasing global warming will affect rainfall in specific regions such as California, Wentz said. Still, his team's analysis of 19 years of planetary rainfall and humidity data hints that global warming might portend "a general tendency to make the wetter areas wetter and the drier areas drier -- which, when it comes to climate change, is a pretty gloomy scenario," he told The Chronicle on Thursday.
Kelly T. Redmond, deputy director of the Western Regional Climate Center at the Desert Research Institute in Reno, called the report a very interesting paper.
"It's the kind of subject we need to be investigating," said Redmond, who is not connected with the Santa Rosa team. "It's a very fundamental issue: What is rainfall on Earth going to do (during) climate change?"
As everyone knows from childhood, the sun evaporates water, causing it to rise into the sky, where it eventually cools and falls back to Earth. The humidity scale reveals how much evaporated water is in the air at any given time.
In the past, climate modelers have generally assumed that as global warming evaporates water and makes the planet more humid, the rainfall rate will rise more slowly. In other words, precipitation won't intensify as fast as the humidity. Initially, the reason seems obvious: Warmer air can hold more water vapor, delaying its eventual cooling and falling back to Earth as raindrops, snow, sleet or hail.
However, when members of the Santa Rosa team analyzed satellite measurements of planetary changes in humidity and rainfall from 1987 to 2006, they were surprised by what they found: Over that period, the global rainfall rate rose at almost exactly the same rate as humidity, like two race NASCAR drivers racing neck and neck. The difference between the rise in rainfall and the rise in humidity was about 1 percent, Wentz said.
"We were very startled by the fact that our absolute numbers are as close to each other," Wentz said. "It casts some doubt on the (earlier computer) models" for how global warming affects precipitation.

http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2007/06/01/BAGD4Q5TM91.DTL&type=science

[Buzz Clik]

1. You can accomplish the same thing by putting Mother Earth's hand in a bucket of warm water.

;)

This one's been done:

http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=115x98404

[ananda]

2. Well, I thought..

that it was going to be wetter in some areas
and dryer in others..

.. which has already started to happen..

.. with climate extremes also already occurring.

GW aint nuthin nice.

[kestrel91316]

3. All GW seems to have given us here in SoCal so far is 119 degrees in

summer and NO RAIN AT ALL in the past year (well, ok, 2 1/2 inches...).