Fewer Clouds Found In Tropics: NASA Scientists Discover New Evidence Of Climate Change

After examining 22 years of satellite measurements, NASA researchers find that more sunlight entered the tropics and more heat escaped to space in the 1990s than in the 1980s. Their findings indicate less cloud cover blocked incoming radiation and trapped outgoing heat. "Since clouds were thought to be the weakest link in predicting future climate change from greenhouse gases, these new results are unsettling," said Dr. Bruce Wielicki of NASA Langley Research Center, Hampton, Va. Wielicki is the lead author of the first of two papers about this research appearing in the Feb. 1, issue of "Science."

"It suggests that current climate models may, in fact, be more uncertain than we had thought," Wielicki added. "Climate change might be either larger or smaller than the current range of predictions."

The observations capture changes in the radiation budget-the balance between Earth's incoming and outgoing energy-that controls the planet's temperature and climate.

The previously unknown changes in the radiation budget are two to four times larger than scientists had believed possible. The reason why and the degree to which it changed are surprising scientists and create a powerful new test for climate models.

Inspired by this puzzle, a research group at NASA Goddard Institute for Space Studies (GISS) developed a new method of comparing the satellite observed changes to other meteorological data.

"The new method is a conceptual breakthrough in how we analyze data," said Anthony Del Genio, a scientist at GISS and co-author of the companion paper.

"What it shows is remarkable," said Wielicki. "The rising and descending motions of air that cover the entire tropics, known as the Hadley and Walker circulation cells, appear to increase in strength from the 1980s to the 1990s. This suggests that the tropical heat engine increased its speed."

The faster circulation dried out the water vapor that is needed for cloud formation in the upper regions of the lower atmosphere over the most northern and southern tropical areas. Less cloudiness formed allowing more sunlight to enter and more heat to leave the tropics.

In response, several of the world's top climate modeling research groups agreed to take on the challenge of reproducing the tropical cloud changes. But the climate models failed the test, predicting smaller than observed variability by factors of two to four. "It's as if the heat engine in the tropics has become less efficient using more fuel in the 90s than in the 80s," said Wielicki. "We tracked the changes to a decrease in tropical cloudiness that allowed more sunlight to reach the Earth's surface. But what we want to know is why the clouds would change."

The results also indicate the tropics are much more variable and dynamic than previously thought.

"The question is, if this fluctuation is due to global climate change or to natural variability," said Del Genio. "We think this is a natural fluctuation, but there is no way to tell yet."

While the current 22-year radiation budget record--the longest and most accurate ever compiled--is still too short to pinpoint a cause, the newly discovered change acts as a standard by which to measure future improvements in cloud modeling.

"A value of this research is it provides a documented change in climate and a target for climate models to simulate," said Del Genio.

Editor's Note: The original news release can be found at http://earthobservatory.nasa.gov/Newsroom/NasaNews/2002/200201317366.html

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Note: This story has been adapted from a news release issued by NASA/Goddard Space Flight Center for journalists and other members of the public. If you wish to quote from any part of this story, please credit NASA/Goddard Space Flight Center as the original source. You may also wish to include the following link in any citation:

Their findings indicate less cloud cover blocked incoming radiation and trapped outgoing heat.

HUH?

Perhaps the reporter meant to write, "Their findings indicate there was less cloud cover blocking incoming solar radiation and a reduced trapping of re-radiated heat (AKA "Greenhouse Effect")

But then the political agenda would fall apart so it's better to confuse you.

"A value of this research is it provides a documented change in climate and a target for climate models to simulate," said Del Genio

And it provides more data for "The Skeptical Environmentalist" to look at too. For pete's sake, scientist's know that the climate changes, always has, likely always will. Man is not a master of this one. So study it another 22 years and get a longer term trend line please. Just don't give this data to greenpeace or the sierra club, there is no doubt what this data will say in their slimy hands.

Sounds like these scientists are competing with Pauxatauny Phil on seeing his shadow.

The real issue they're failing to define is whether or not my boating season is affected here in Western N.Y. That's all that really matters.

Huh?

I think it's a very roundabout way of them saying the satellite measurements indicated a decrease in tropical temperatures from the 1980s through the 1990s. The presumed lack of clouds and increased radiational cooling is their excuse.

It all has to do with a drop in temperature but they won't say that. Instead "their findings indicate less cloud cover blocking incoming radiation and trapped outgoing heat". I.e., an excuse for atmospheric cooling.

My confusion is in how that sentence is written. Read it again:

Their findings indicate less cloud cover blocked incoming radiation and trapped outgoing heat.

That sentence says that clouds allow incoming radiation and allow heat to escape the atmosphere, which is wrong. I think they meant to say:

Their findings indicate less cloud cover blocking incoming radiation and trapping outgoing heat.

No doubt a natural phenomena which will be turned into the next Greenpiss fund raising effort. If approached, ask them "why" the temperature of Mars is rising.

I'm sure the answer is that it is a direct result of all the exhaust from retro rockets fired off while trying to explore Mars.

I'm referring to atmospheric temperature measurements, not ground temperature measurements. I believe the article is too. By having less clouds less heat will be collected and preserved in the atmosphere, hence there will be lower observed atmospheric temperatures. The key I believe is where they say the measurements "indicate" and then go into their cloud hypothesis. Iow, it seems their whole cloud hypothesis is an attempt to explain what the satellite measurements show. They just don't want to say what those measurements are. Nope, they'll let us know what the secret measurements indicate without letting us know what the measurements show.

Their argument seems to be: less clouds = less heat retained by the atmosphere which = the atmospheric satellite data gathered from the 1980s - 1990s [i.e., lower atmospheric temperatures reported by the satellite]. They just want to leave out what the satellite data actually shows and jump to a hypothesis to account for it.

"The observations capture changes in the radiation budget-the balance between Earth's incoming and outgoing energy-that controls the planet's temperature and climate."

A fancy way of saying these are nothing more than atmospheric temperature measurements. So, since "more heat went out of the atmosphere in the 1990s" simply means atmospheric temperatures in the tropics dropped in the 1990s.

Water vapour in the atmosphere (clouds) is the strongest green house gas. Or the green-house gas with the biggest effect on the global climate. This is rarely mentioned in the GW debate.

Water is very hard to model and can cause drastic warming or cooling depending upon the type and altitude of the clouds formed. Adding water to the climate prediction models could either suppress warming predictions or it is simply too compilcated to add to the current models.

"It suggests that current climate models may, in fact, be more uncertain than we had thought," Wielicki added. "Climate change might be either larger or smaller than the current range of predictions."

The climate people are gradually preparing to tell us the models are wrong and warming won't be serious. Earlier this month they said Antartica is cooling in contradiction to the models. Ice there is growing in contradiction to the models. The middle atmosphere is not warming in contradiction to the models. Next they will be saying the land warming is caused by urban heat islands after all.

The theory is in big trouble and the scientists are desparately trying to escape being associated with it before their reputations are totally destroyed.

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