STORY: Jan Curtis doesn't consider himself a pariah among his peers in the scientific community. Rather, he thinks of himself as a healthy skeptic when it comes to blaming people for a warmer global climate.
CURTIS: "There just isn't enough information available to come to any kind of conclusion."
Curtis is a climatologist at the University of Alaska Fairbanks. He sees his role in the debate not as one who researches climate but as one who tests the results and questions the conclusions of others.
CURTIS: "Our perspective is to take the available data, apply statistical methodology to it and to determine what is good and bad about the data, and then come up with conclusions that we can feel pretty confident about."
Curtis agrees with his colleagues that the world's climate has gotten warmer during the last century. But it's the causes of this warming he finds elusive. He says the computer models scientists use to predict the ability of greenhouse gases like carbon dioxide to warm the climate are flawed.
CURTIS: "The general circulation model is a theoretical basis model that takes into account various weather elements. The problem with the model is that the spatial resolution of the data is too coarse. The separation between data points is far wider than in any of the forecasting models that look at weather on a daily or weekly basis. So we're missing a lot of data. The models make the earth very simplified where you have land and water and they don't take into account the topography of mountain ranges."
Curtis says water vapor is the wild card in climate change models.
CUTRIS: "Water vapor is far more important because just a one-percent change in water vapor can have the same effect as doubling the amount of carbon dioxide. So, if we are warming, which we are, in all likelihood that will increase the amount of evaporation off oceans and lakes, and therefore you get more clouds in the sky. And clouds work both ways. They can either reflect sunlight back into space or trap the heat near the earth's surface."
Beyond the fallibility of the computer models, Curtis says scientists have largely ignored the many natural cycles that drive the world's climate.
CURTIS: "We know that in the past that there have been temperatures considerably warmer than they are now, and considerably colder. So there's obviously a natural signature that may be much more of an influence than human impacts on climate. The last real warm winter we had that was record-setting was 70 or 80 years ago. We certainly didn't have the same issues with carbon dioxide and the like then."
In factand this is sure to raise some eyebrowsCurtis says there's some evidence to suggest that the climate, rather than getting warmer, may actually be cooling.
CUTRIS: "In 1976, at least in the Northern Hemisphere, there was a shift in the weather patterns such that the temperatures for the next 20 years were increasing. However, in the last two or three years, despite the warm winter we had here last year, temperatures have actually been decreasing. Whether or not that's because of more cloudiness in the summer and less cloudiness in the winter or a half dozen other possibilities, climate and weather are always changing."
OUTRO: This is Arctic Science Journeys Radio, a production of the Alaska Sea Grant Program and the University of Alaska Fairbanks. I'm Doug Schneider.
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Thanks to the following individual for help preparing this script:
Jan Curtis, climatologist
Arctic Science Journeys is a radio service highlighting science, culture, and the environment of the circumpolar north. Produced by the Alaska Sea Grant College Program and the University of Alaska Fairbanks.
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Related Web sites
A Closer Look at Global Warming, National Research Council Report on Climate Change