Here's an in-depth look at both sides of the global warming debate from the Casper Star Tribune. From the article, "The words 'global warming' provoke a sharp retort from Colorado State University meteorology professor emeritus William Gray: 'It's a big scam.' And the name of climate researcher Kevin Trenberth elicits a sputtered 'opportunist.' At the National Center for Atmospheric Research, where Trenberth works, Gray's name prompts dismay. "Bill Gray is completely unreasonable," Trenberth says. 'He has a mind block on this.' Only 55 miles separate NCAR's headquarters, nestled in the Front Range foothills, from CSU in Fort Collins. But when it comes to climate change, the gap is as big as any in the scientific community...
"Science by its nature is disputatious -- with every idea challenged, tested and retested. It's always been that way. In the 18th century, Sir Isaac Newton and Gottfried Leibniz sparred over claims to the discovery of calculus. About 140 years later, Charles Darwin's theory of evolution was challenged -- based on the science of the day -- by Harvard University professor Louis Agassiz and the British Museum's Sir Richard Owen. Now the battle is over global warming, or more accurately over myriad details -- like temperature readings and the thickness of sea ice -- upon which the larger idea is based. On one hand, the fight is a natural part of the scientific process. But it also creates dissonance and uncertainty...
"Still, a broad scientific consensus has emerged that human activity is contributing to climate change. Findings by panels created by the National Academy of Science to resolve disputes -- such as conflicting satellite and ground temperature records -- have supported the trends in global climate change. And things that the NCAR models predict -- such as thinning sea ice and melting glaciers -- are coming to pass, although scientists say more data are needed to verify those trends.
"After more than two decades of research, scientists, even most skeptics, agree that: Since 1750, the amount of carbon dioxide in the atmosphere, mainly from burning fossil fuels, has risen to about 380 parts per million from 286 parts per million; It doesn't appear carbon dioxide levels have been that high in the past 650,000 years; Carbon dioxide is continuing to build in the atmosphere by about 1.5 parts per million a year, and as a so-called greenhouse gas, it traps the sun's heat; The Earth's average temperature has warmed about 1 degree Fahrenheit since 1880 and is now warmer than it has been in the past 400 years; Average global temperatures are likely to rise -- this is where the debate begins -- somewhere between 2 and 10 degrees Fahrenheit by 2100; The heat will cause global ocean levels to rise 3 to 39 inches this century...
"While [Roger Pielke Sr.] agrees carbon dioxide is forcing changes in the climate, he says, 'It is not the only forcing.' Man-made changes to the land, in addition to about 30 other greenhouse gases -- some man-made, some natural -- may play an even bigger role, he said. 'The public likes simple answers,' Pielke said. 'But there isn't any simple answer here.' Simplicity is hard to come by because Earth is a giant, complex heat-moving machine. The sun's rays strike full force at Earth's middle and glance off the ends -- making the equator hotter than the poles. Ocean currents, winds, the jet stream and hurricanes are forces trying to balance out the Earth's heat. Efforts to calculate what is going on in the oceans, the land and the atmosphere are an unparalleled exercise...
"Efforts to calculate what is going on in the oceans, the land and the atmosphere are an unparalleled exercise. The task falls to mathematical models run by supercomputers like the one in NCAR's basement. These 'general circulation models' attempt to keep track of a multitude of variables around the globe -- such as ocean currents, air and sea temperatures, rainfall and the composition of the atmosphere. 'This is a unique exercise in science and a very difficult one,' said Christopher Essex, a mathematician at the University of Western Ontario in Canada. The models are trying to project a future world, Essex said, without a complete theoretical base on how climate works and the risk of small errors being amplified. Another problem, Essex said, is in the inability to do controlled experiments -- one of science's key tools. 'There's only one atmosphere, so you can't hold everything steady and change just one variable to see what happens,' he said...
"There are other phenomena affecting global temperatures over time, such as El Nino, a Pacific Ocean warm-water mass that appears in roughly five-year cycles and changes world weather patterns. And there is the Atlantic thermohaline current, a conveyor belt moving heat north on the surface and then dropping it to the ocean floor and heading back to the equator -- a 1,200-year trip. Changes in the current lead to changes in temperature. Somehow the models have to account for these natural variations, too. Gray believes that the warmer temperatures in the Northern Hemisphere are linked to a natural slowing in the thermohaline current, not the carbon dioxide. Some of the models also show the current is slowing and that, along with warming oceans, adds to hurricane risks."
"2008 pres"
8:07:58 AM 
|
|
