Earthsky Interviews
Private: Don’t blame the sun for recent climate change, says expert
August 17, 2008 - Earth
We’re speaking with Caspar Ammann, climate scientist at “NCAR”:http://www.ncar.ucar.edu/ – the National Center for Atmospheric Research in Boulder.
_Caspar Ammann_: The naturally driven world that seemed to have, in our understanding, when we try to model it, or try to understand it in reconstructions, it seems to work with solar variability, volcanoes that go off. It seems to work quite well. But when we come to the last 30, 50 years, something else is going on.
Like most climate scientists, Ammann believes that ’something’ is not the sun.
_Caspar Ammann_: And when we look at the sun, if the sun could be increasing, well, there’s not a single measure of solar variability, be it sunspots, be it flares, be it cosmic rays. There is no trend whatsoever over the last 50 years. Yet it is this period that we identify as having the fingerprint of greenhouse gas changes._
He said a warmer sun would cause warming high in Earth’s stratosphere. But this isn’t happening, according to Ammann.
_Caspar Ammann_: What our satellites and radiosondes and rockets are telling us is that above the tropopause, temperatures are dropping, and a drop in temperatures, that does not fit with a change in solar radiation. But it fits very nicely with an increase in greenhouse gases.