When dealing with the latest hysterical claims about global warming, it's essential to keep in mind a fundamental principle of science: Theories must be testable. A scientific theory describes a predicted outcome and one or more means by which the theory can be tested.
Far from supporting a sound scientific theory that humans are creating a global warming crisis, the recent assertion by prominent global warming alarmists that Antarctica is getting warmer illustrates the flip-flopping nature of global warming predictions.
Antarctica was first inserted into the debate when Al Gore, in his movie An Inconvenient Truth, referred to Antarctica as a ''canary in the coal mine'' indicating human-induced climate change. After Gore asserted icebergs breaking off the West Antarctic ice sheet proved Antarctica was feeling the effects of human-induced global warming, real scientists pointed out that most of Antarctica has been getting colder for decades. Although a small portion of West Antarctica is warming, scientists noted this was the exception to an overall Antarctic cooling pattern.
Embarrassed that their most high-profile spokesperson had been caught cherry-picking the data and misrepresenting temperature trends, the global warming crowd rolled out Plan B. In February 2008 a Web site administered by prominent global warming alarmist Michael Mann featured an article acknowledging that indeed Antarctica has been getting colder, but asserting, ''a cold Antarctica is just what calculations predict ... and have predicted for the past quarter century. ... Bottom line: A cold Antarctica and Southern Ocean do not contradict our models of global warming. For a long time the models have predicted just that.''
So the party line in 2008 was, ''Of course Antarctica is cooling. This is what our global warming theory predicts. This is what our global warming theory has always predicted. A cooling Antarctica is therefore more evidence that humans are causing a global warming crisis.''
The 2008 party line was weak, and the American public knew it. Significantly, the alarmists could not point to previously published predictions of human-induced global warming causing Antarctica to cool.
Enter, once again, Michael Mann.
Disregarding his own Web site's 2008 assertion that human- induced global warming would cause Antarctica to cool, Mann and colleagues on January 22 published an article in Nature claiming Antarctica is warming. Mann's Web site now speculates that humans may be causing Antarctic warming.
Despite the claims of Mann and company in their Nature article, NASA satellite instruments and most Antarctic ground temperature stations show Antarctica has been cooling. Mann and his colleagues rely on highly subjective, controversial, and self-serving ''data-smoothing'' to assert that all the other temperature reports are wrong.
Beyond the dispute over the alarmists' blatant manipulation of data, the larger and more important issue is that global warming theory is no longer a testable scientific theory - assuming it ever was one. The alarmists claimed Antarctica was warming because of a human-induced climate crisis. When it was shown Antarctica is cooling, the alarmists flip-flopped and claimed Antarctic cooling indicated a human-induced climate crisis. When that party line was no longer convenient, they flip-flopped again.
Sound science dictates that a theory be testable and conform to known facts. When it is asserted that anything and everything that could possibly happen is consistent with, and indeed affirmative evidence for, a certain set of beliefs, that is not science. That is religion, and nothing more.
James M. Taylor (firstname.lastname@example.org) is senior fellow for environment policy at The Heartland Institute.