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HomeMy WebLinkAbout2006/08/01 Special Orders -===-~c'<.'~\ o~v, UNION TRIBUNE Cold, hard facts about global warming By Peter Doran July 28, 2006 In the debate on global warming, the data on the climate of Antarctica have been distorted, at different times, by both sides. As a polar researcher caught in the middle, I'd like to set the record straight. In January 2002, a research paper on Antarctic temperatures, of which I was the lead author, appeared in the journal Nature. At the time, the Antarctic Peninsula was warming, and many people assumed that meant the climate on the entire continent was heating up, as the Arctic was. But the Antarctic Peninsula represents only about 15 percent of the continent's land mass, so it could not tell the whole story of Antarctic climate. Our paper made the continental picture more clear. My research colleagues and I found that from 1996 to 2000, one small, ice-free area of the Antarctic mainland had actually cooled. Our report also analY2ed temperatures for the mainland in such a way as to remove the influence of the peninsula warming and found that, from 1966 to 2000, more of the continent had cooled than had warmed. Our summary statement pointed out how the cooling trend posed challenges to models of Antarctic climate and ecosystem change. Newspaper and television reports focused on this part ofthe paper. And many news and opinion writers linked our study with another bit of polar research published that month, in Science, showing that part of Antarctica's ice sheet had been thickening - and erroneously concluded that the Earth was not warming at all. "Scientific findings run counter to theory of global warming," said a headline on an opinion column in The San Diego Union-Tribune. One conservative commentator wrote, "It's ironic that two studies suggesting that a new Ice Age may be under way may end the global warming debate." In a rebuttal in The Providence Journal, in Rhode Island, the lead author of the Science paper and I explained that our studies offered no evidence that the earth was cooling. But the misinterpretation had already become legend, and in the four-and-one-half years since, it has only grown. Our results have been misused as "evidence" against global warming by Michael Crichton in his novel "State of Fear" and by Ann Coulter in her latest book, "Godless: The Church of Liberalism." Search my name on the Web, and you will find pages of links to everything from climate discussion groups to Senate policy committee documents - all citing my 2002 study as reason to doubt that the Earth is warming. One recent Web column even put words in my mouth. I have never said "the unexpected colder climate in Antarctica may possibly be signaling a lessening of the current global warming cycle." I have never thought such a thing either. Our study did find that 58 percent of Antarctica cooled from 1966 to 2000. But during that period, the rest of the continent was warming. And climate models created since our paper was published have suggested a link between th'e lack of significant warming in Antarctica and the ozone hole over that continent. These models, conspicuously missing from the warming-skeptic literature, suggest that as the ozone hole heals - thanks to worldwide bans on ozone-destroying chemicals - all of Antarctica is likely to warm with the rest of the planet. An inconvenient truth? Also missing from the skeptics' arguments is the debate over our conclusions. Another group of researchers who took a'different approach found no clear cooling trend in Antarctica. We still stand by 011r rpsl1lts for tne nerion we ;1n<11vZf~rl. hnt ]lnhiasecl renortine- W0111i1 adrnowlf':cle-p ciifferenc.ps of scientific opinion. The disappointing thing is that we are even debating the direction of climate change on this globally important continent. And it may not end until we have more weather stations on Antarctica and longer-term data that demonstrate a clear trend. In the meantime, I would like to remove my name from the list of scientists who dispute global warming. I know my coauthors would as well. . Doran is an associate professor of earth and environmental sciences at the University of Illinois at Chicago. Copyright Union- Tribune Publishing Co. Ju/12, 2006 Richard C.J. Somerville As a climate scientist, I am often asked, "Do you believe in global warming?" Climate change, however, is not a matter of personal belief Instead, among experts, it's just settled science that peopie are changing the climate. The intergovemmentai Panel on Climate Change, or IPCC, reported in 2001 that, "There is new and stronger evidence that most of the warming observed over the iast 50 years is attributable to human activities." Every reputable scientific organization that has studied the IPCC conclusion has endorsed it. Recent research (http:// realclimate.org) reinforces this assessment. The next major IPCC report, due in 2007, is iikely to cite more supporting evidence. AI Gore's film and book, "An Inconvenient Truth," do a fine job of summarizing the science. You may agree or disagree with Gore politically, but nobody can deny that he has maintained a serious interest in climate change for some two decades and has become quite knowledgeable about it. For San Diegans, it's a fascinating bit of history that Gore first learned about this issue as a Harvard student in the 1960s. His teacher was our own Roger Revelle. Before moving to Harvard, Revelle had been director of Scripps Institution of Oceanography and a founder of the University of California San Diego. The Earth as a whole is always in approximate energy balance, absorbing energy from sunlight and emitting an equivalent amount of energy to space as infrared radiation. Some infrared energy is emitted directly from the surface of the Earth. The rest is emitted from the atmosphere, by clouds and particles and the gases (chiefly water vapor and carbon dioxide) that contribute to the greenhouse effect. Incidentally, we know that the amount of carbon dioxide in the atmosphere has increased substantially in recent decades, because this increase has been measured very accurately. The measurements were initiated by Charles David Keeling (1928~ 2005) whom Revelle brought to Scripps institution of Oceanography in the 1950s. Keeling, who spent his entire career at Scripps, discovered that human activities are changing the chemical composition of the global atmosphere. Carbon dioxide is produced by burning fossil fuels. Adding carbon dioxide to the atmosphere means that more of the energy emitted to space must come from higher (hence colder) levels of the atmosphere. The Earth will respond to this new situation by warming up, thus emitting more infrared energy, until the equilibrium is restored. That's our fundamental scientific understanding. It comes from rock-solid, well-understood physics. Everything else, from heat waves to hurricanes, is fascinating and important, but that is really just the details, scientifically speaking. Working out all the detaiis will take a long time. But a promising start has been made, and climate science can already usefuily inform policy. In a similar way, you might say that an ultimate goal of medical science is to eliminate ail disease. That this task is incomplete is no reason to treat your physician with disdain. A group of people dispute the scientific consensus. They like to call themselves skeptics. A healthy skepticism, however, is part of being a good scientist, so I am unwilling to surrender this label to them. Instead, I cail them denialists. You don't get any1hing iike a balanced view from climate deniaiists. Their only goal is finding ways why the climate might be resistant to human activities. By and large, these denialists have convinced very few knowledgeable scientists to agree with them. Experience shows that in science, it tends to be the exception rather than the rule when a lone genius eventually prevails over conventional wisdom. An occasional Galileo does come along, but not often, and nearly all the people who think they are a Galileo are actuaily just wrong. Science is very much a cooperative process and is largely self- correcting. We publish our research methods and our findings in detail and invite other scientists to confirm or disprove them. Incorrect science ultimately gets rooted out and rejected. What of the future? I can imagine both an optimistic and a pessimistic scenario. In my optimistic scenario, climate science informs the making of wise public policy. Technological creativity then leads to rapid development of practical energy aiternatives to fossil fueis. We stabilize the Earth's greenhouse effect before it gets too strong. My pessimistic scenario is a different planet, with sea level much higher and dangerously altered weather patterns. You cannot fool nature. Climate science warns us that strengthening the greenhouse effect must eventually produce serious consequences. That's not radical environmental alarmism. It's physics. For me, the issue then becomes one of guessing whether we get wise before that day, or whether we must wait for some shocking and unpleasant climate surprise that wakes us all up. For my children's sake, I hope that the optimistic scenario is the one that develops. The choice is ours to make.