That’s what the casual reader must take from the December 3 issue of Science, and the same day’sWashington Post, citing the work of University of Maryland’s Konstantin Ya Vinnikov. Who claims that the well-known (but slight) recession of Arctic sea ice that has occurred in the last five decades is caused by human-induced climate change. The reason, Vinnikov says, is that computer models using greenhouse gas warming and sulfate aerosol cooling melt only about as much summer arctic sea ice as has already been lost. When run without human influence, the computer models melt this much ice only 2 percent of the time. We don’t worry about winter ice because everything is frozen up there in that season.
To be fair to the Post, science writer Curt Suplee went out of his way to point out the highly controversial nature of the finding, and that there’s a reasonable argument that Vinnikov’s finding isn’t as solid as it is cracked up to be. But Suplee didn’t have the space to go into the gory details. The problem lies in the “logic” of the study, in which a computer model is used to “prove” something. That requires that the model be correct. But every global warming model has gotten the behavior of 80 percent of the lower atmosphere wrong over the last quarter century, predicting warming where there was none. Because the atmosphere is a stirred fluid, correctly predicting the warming that occurred in the remaining 20 percent can only mean that the right answer was arrived at for the wrong reason.
Welcome to 21st century science! Perhaps, instead of comparing two computer models, it might be better to see if warming is human induced by looking at the actual temperature history.
Let’s stipulate that the decline in Arctic sea-ice is real. But is it a consequence of the largely unknown behavior of the world’s largest natural highball glass? The Arctic Ocean contains the largest mass of floating ice on earth. Lest folks worry that melting this ice will inundate Miami, they might pour a scotch and soda and watch the ice melt. The “sea level” remains the same, even as the drink goes stale. I’ll drink to the notion that a lot of the observed melting is simply a continuation of a long-term process that initially had nothing to do with people.
We have a pretty decent history of Arctic temperatures, thanks to the Cold War. That history begins in 1958–about the time we realized we had to know a lot about the Arctic atmosphere, owing to a long-standing dispute with our nuclear-armed adversaries across the pole. The temperature history has been summarized and is continually updated by Department of Commerce scientist James Angell. What it shows certainly complicates Vinnikov’s computer-based analysis.
As is plain and clear, there is no warming at all in the first three decades of these measurements. Then a trend sets in, beginning in 1988, a mere decade ago. How can one melt the ice from 1950 through 1988 when there is no regional warming? In fact, it looks like the ice was in the process of melting long before the initiation of putative human greenhouse warming. Even worse, the period from 1950 to 1975 was one of cooling in the Northern Hemisphere, and still the ice melted.
A more logical explanation than what appears in Science is that the ice has been responding to a rapid and dramatic 2 degree centigrade warming of the Arctic that took place from 1920 to 1940. In other words, it takes many decades for the sea and the ice to adjust to past thermal imbalance. Is this Arctic warming really such a terrible thing? Scientists are pretty sure that the earth was about 1.5ºC warmer 4000 to 7000 years ago than it is now (although there is uncertainty as to why). That means that the summer Arctic ice had to have receded considerably beyond its current position. That era, known as the “hypsithermal period,” was also called the “climatic optimum” in previous generations of textbooks (written before the current “hysterical period”), because it accompanied the rise of agriculture and civilization.
Maybe it’s not an accident after all that crops are growing better than ever and people are getting rich.
