Troposphere is warming too, decades of data show
Not only is Earth's surface warming, but the troposphere -- the lowest level of the atmosphere, where weather occurs -- is heating up too, U.S. and British meteorologists reported on Monday.
In a review of four decades of data on troposphere temperatures, the scientists found that warming in this key atmospheric layer was occurring, just as many researchers expected it would as more greenhouse gases built up and trapped heat close to the Earth.
This study aims to put to rest a controversy that began 20 years ago, when a 1990 scientific report based on satellite observations raised questions about whether the troposphere was warming, even as Earth's surface temperatures climbed.
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, according to Dian Seidel, research meteorologist for the U.S. National Oceanic and Atmospheric Administration.
It was relatively easy to track surface temperatures, since most weather stations sat on or close to the ground, Seidel said by telephone from NOAA's Air Resources Laboratory in Silver Spring, Maryland, outside Washington.
Measuring temperature in the troposphere is more complicated. Starting in the late 1950s, scientists dangled weather instruments from big balloons, with the data sent back to researchers by radio transmission as the balloons rose through the six miles of the troposphere.
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