Lower Atmosphere is Warming

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Contact: Jana Goldman *FOR IMMEDIATE RELEASE*

301-734-1123, jana.goldman@noaa.gov
jana.goldman@noaa.gov                            Nov. 15, 2010

*Review of Four Decades of Scientific Literature Concludes Lower Atmosphere is Warming*

             The troposphere, the lower part of the atmosphere closest
to the Earth, is warming and this warming is broadly consistent with
both theoretical expectations and climate models, according to a new
scientific study that reviews the history of understanding of
temperature changes and their causes in this key atmospheric layer.

             Scientists at NOAA, the NOAA-funded Cooperative Institute
for Climate and Satellites (CICS), the United Kingdom Met Office, and
the University of Reading in the United Kingdom contributed to the
paper, "Tropospheric Temperature Trends: History of an Ongoing
Controversy," a review of four decades of data and scientific papers to
be published today by Wiley Interdisciplinary Reviews - Climate Change
http://onlinelibrary.wiley.com/doi/10.1002/wcc.80/abstract, a
peer-reviewed journal.

             The paper documents how, since the development of the very
first climate models in the early 1960s, the troposphere has been
projected to warm along with the Earth's surface because of the
increasing amounts of greenhouse gases in the atmosphere. This
expectation has not significantly changed even with major advances in
climate models and is in accord with our basic physical understanding of
atmospheric processes.

             In the 1990s, observations did not show the troposphere,
particularly in the tropics, to be warming, even though surface
temperatures were rapidly warming. This lack of tropospheric warming was
used by some to question both the reality of the surface warming trend
and the reliability of climate models as tools. This new paper
extensively reviews the relevant scientific analyses --- 195 cited
papers, model results and atmospheric data sets --- and finds that there
is no longer evidence for a fundamental discrepancy and that the
troposphere is warming.

             "Looking at observed changes in tropospheric temperature
and climate model expectations over time, the current evidence indicates
that no fundamental discrepancy exists, after accounting for
uncertainties in both the models and observations," said Peter Thorne, a
senior scientist with CICS in Asheville, N.C and a senior researcher at
North Carolina State University. CICS is a consortium jointly led by the
University of Maryland and North Carolina State University.

             This paper demonstrates the value of having various types
of measurements --- from surface stations to weather balloons to
satellites --- as well as multiple independent analyses of data from
these observation systems.

             "There is an old saying that a person with one watch always
knows what time it is, but with two watches one is never sure," said
Thomas Peterson, lead scientist at NOAA's National Climatic Data Center.
"The controversy started with the production of the first upper-air
temperature 'watch' in 1990, and it was only later when multiple
additional 'watches' were made by different 'manufacturers' that we
learned that they were each a few minutes off. Although -researchers all
agree the temperature is increasing, they disagree how much."

             And while this is the first comprehensive review of the
scientific literature on this topic, it is not the last word on the
tropospheric temperature trend.

             "Looking to the future, it is only through robust and
varied observations and data analyses that we can hope to adequately
understand the tropospheric temperature trend," said Dian Seidel, a NOAA
scientist at the Air Resources Laboratory, in Silver Spring, Md.

             The study was funded by UK Department of Energy and Climate
Change, the UK Department of Environment, Food and Rural Affairs and NOAA.

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