November 16, 2010

Earth’s Troposphere Is Heating Up

U.S. and British meteorologists said on Monday that not only is Earth's surface warming, but the troposphere is heating up also.

The scientists found that warming in this key atmospheric layer was occurring, just as many researchers expected as more greenhouse gases build up and trap heat close to the Earth.

This study put to rest a controversy that began 20 years ago when a 1990 scientific report raised questions about whether the troposphere was warming, even as Earth's surface temperatures climbed.

According to Dan Seidel, research meteorologist for the U.S. National Oceanic and Atmospheric Administration (NOAA), the original discrepancy between what the climate models predicted and what satellites and weather balloons measured had to do with how the observations were made.

Seidel told Reuters that it was relatively easy to track surface temperatures, since most weather stations sat on or close to the ground.

Measuring temperature in the troposphere is more complicated.  Scientists dangled weather instruments from big balloons, with data sent back to researchers by radio transmission as the balloons rose through the six miles of the troposphere.

Seidel said that the first satellite data on troposphere temperature was gathered in 1979, but neither weather balloons nor these early satellite weather observations were accurate measures of climate change.

"They're weather balloons and weather satellites, they're not climate balloons and climate satellites," she said. "They're not calibrated precisely enough to monitor small changes in climate that we expect to see."

NOAA said in a statement that when the 1990 study was published, it prompted some to question the reality of surface warming and whether climate models could be relied upon.

The new study reviewed 195 cited papers, climate model results and atmospheric data sets, and found no fundamental discrepancy between what was predicted and what is happening in the troposphere.  The study found that it is warming.

Scientists at NOAA, the United Kingdom Met Office and the University of Reading contributed to the paper, which was published in Wiley Interdisciplinary Reviews - Climate Change.

International climate change talks are expected to take place on November 29 in Cancun, Mexico.  However, prospects for a global deal to curb greenhouse emissions are considered slim.


Image Caption: A view of Earth's troposphere from an airplane. Credit: Nick Juhasz/Wikipedia   


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