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Wednesday, February 18, 2009

Cherry-Picked Facts Heat Up Climate Debate

By John Fleck
Of the Journal
      There is an old canard of the political debate around climate change that goes something like this: How can scientists be believed about global warming today when back in the 1970s they predicted global cooling?
    The argument, reprised in Sunday's Journal by syndicated columnist George Will, sounds reasonable, and gets good traction in the political debate.
    It is wrong.
    There was no widespread belief among scientists in the 1970s about a coming ice age. Will engages in an egregious case of cherry-picking, plucking quotes that seem to support his assertion while ignoring a vast body of literature that does not.
    To give but one example: Will quotes a 1975 Science News article as predicting "a full-blown 10,000-year ice age".
    The 1970s were an interesting time in climate science. Global temperatures were cooling at the time, and some scientists were struggling to understand why. Was it variations in solar radiation caused by oscillations in Earth's orbit? Could aerosol pollution be blocking the sun?
    Meanwhile other researchers were piecing together the story of greenhouse gases being emitted by fossil fuel burning, and considering the possibility that they could warm the planet.
    If you read the full 1975 Science News article, rather than Will's hand-picked quote, you get a different picture. "The cooling trend observed since 1940 is real enough, (C.C. Wallen of the World Meteorological Organization) says, but not enough is known about the underlying causes to justify any sort of extrapolation."
    The article goes on to say: "Stephen H. Schneider of the National Center for Atmospheric Research says that by the turn of the century, enough carbon dioxide will have been put into the atmosphere to raise the temperature of earth half a degree."
    In other words, the 1975 Science News article, rather than predicting a coming ice age, summarizes the uncertainty of the day.
    But it is important to go beyond any single article. If Will and the others who make the "global cooling" argument take it seriously, it seems incumbent on those interested in the climate change debate, to go back and look as broadly as possible at what scientists were really saying in the 1970s. If they got it wrong, we should understand how, so we can learn from and avoid their mistakes.
    The result of that exercise? The notion of widespread scientific belief in the 1970s in "global cooling" is a myth, according to a peer-reviewed paper published last fall in the Bulletin of the American Meteorological Society. I am one of the authors of the paper, a scholarly project carried out separate from my newspaper duties. The other authors were Tom Peterson of the National Climatic Data Center and William Connolley, formerly of the British Antarctic Survey.
    The paper involved a thorough review of the scientific literature of the day, in an attempt to move beyond the anecdotes cited by Will and others.
    We found that, rather than predicting a coming ice age, the majority of researchers working in the 1970s thought greenhouse warming was likely to quickly dominate any factors that might be contributing to the short-term cooling then underway.
    When George Will last wrote about this subject, in May 2008, I sent him a copy of the 1975 Science News article, hoping he might get a fuller picture of what was going on at the time. I got a nice note back from him thanking me for sharing it. It doesn't seem as if he read it, which would have been nicer.
    This is not the only factual error Will mustered in Sunday's column.
    "According to the University of Illinois' Arctic Climate Research Center," Will wrote, "global sea ice levels now equal those of 1979.
    Here's what the folks at the University of Illinois had to say in response: "We do not know where George Will is getting his information, but our data shows that on February 15, 1979, global sea ice area was 16.79 million sq. km and on February 15, 2009, global sea ice area was 15.45 million sq. km.
    Therefore, global sea ice levels are 1.34 million sq. km less in February 2009 than in February 1979. This decrease in sea ice area is roughly equal to the area of Texas, California, and Oklahoma combined."
    George Will is entitled to his own opinions. He is not entitled to his own facts.
    John Fleck's covers science for the Journal. Visit his blog at abqjournal.com/weblogs/fleck.htm