Tropopause Rises 200 Meters 1979-1999 - PhysicsWeb

[hatrack]

"Scientists have shown that human activity is having an impact on the height of the tropopause - the boundary between the troposphere (the lowest layer of the atmosphere) and the stratosphere. The height of the tropopause increased by about 200 metres between 1979 and 1999, and Benjamin Santer of the Lawrence Livermore National Laboratory in the US and colleagues in Germany, the UK and the US have used computer models to show that about 80% of this increase was directly caused by human activity (B Santer et al. 2003 Science 301 479).

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Santer and colleagues modelled climate changes caused both by man-made factors such as greenhouse gases, atmospheric ozone and sulphate aerosols, and by natural phenomena such as changes in solar activity and volcanic eruptions. 'We examine the output from the models and compare this with observations,' Santer told PhysicsWeb. 'In the model world we can change one factor at a time, while holding the others constant. This allows us to isolate and quantify the effect of individual factors.'"

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http://physicsweb.org/article/news/7/7/18