Changes in global temperature and sea levels reflect natural fluctuations that have occurred throughout history and are not caused by pollution, according to an environmental professor who spoke at a UNM forum Thursday.
Fred Singer of the University of Virginia, is an atmospheric physicist who has worked on satellite weather studies for several government agencies. He said that while sea levels are rising, the temperature is not and recent concern that human activity will lead to climate change is unfounded. His presentation, "Global Warming: Fact or Fiction," was part of an annual series of talks sponsored by Sigma Xi, an interdisciplinary science honor society.
"Scientists ignore data," he said, as he presented temperature study results that showed natural fluctuations over several centuries. "If you have a hypothesis that you strongly believe in, you tend to ignore data that contradicts it."
According to Singer's data, which came from various entities, including the U.N.-based Intergovernmental Panel on Climate Change, temperatures did warm from about 1850 until 1940, but have dropped ever since despite the spike in industry after World War II.
Based on studies of ocean sediments, the temperature has been gradually cooling for about 3,000 years.
During the last 20 years, a period in which many have suggested evidence of warming from the greenhouse effect, various methods of measurement have provided conflicting data, Singer said. Sensors that measure surface and ocean temperature have recorded temperature increases, while satellite and balloon weather equipment have showed no warming.
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"With increasing greenhouse gasses, you would expect the atmosphere to get warmer," he said.
Singer said urban encroachment on weather-measuring instruments, which are often located near airports, has resulted in some of the disagreement.
"Where people live, it is getting warmer," he said.
Ocean temperatures are measured by ships, often at inlets for engine cooling water, which measure at inconsistent depths, he said.
One American Meteorological Society study of California showed an increase of temperatures in the urban areas, but none in the rural areas, he said.
"We all know the center of a city is always warmer than the suburbs," he said.
Singer showed several examples of data retrieved by what he called proxy measurements - measuring something related to temperature and deducing that temperature. Scientists have used tree rings, ice cores, coral, cave stalactites and other geological formations to get proxy measurements of temperatures from 100,000 years ago, he said.
Proxy data shows a warm period at about 1,000 A.D., which Singer said corresponded historically with a fertile era, followed by a little ice age until the mid-19th century, which was characterized by increased starvation and disease.
The last ice age was about 20,000 years ago and temperatures have remained relatively the same since then.
"Proxy data have not found any data showing any warming trend after 1940," Singer said. "Before that, yes."
Recorded sea level changes have shown a linear increase of about seven inches per century, Singer said. But since a steep rise between four and 5,000 years ago, corresponding to the warm period, the ocean has risen at about the same rate, irrespective of whether or not the climate has warmed or cooled, he said.
Melting glaciers and expansion from warming plays a small role in the rising sea level, he said, but the real culprit is the slowly melting western ice sheet of Antarctica, a phenomenon that has taken place for thousands of years.
"This is on a millennial scale - it's not affected by the climate now," he said. "The sea level will keep rising at the same rate no matter what we do."
As for what can be done about global warming, he said, "the answer is: very little."
He said though he didn't believe the temperature was changing, even if it did, scientists were in disagreement over whether or not that would be a bad thing.
He compared a 1999 study by the U.N. panel that found a 200 percent increase in carbon dioxide would lower the gross domestic product of countries due to agricultural problems caused by climate change to one by Yale professor Robert Mendelsohn that found the opposite. Some predict carbon dioxide will double within 50 years, he said.
"(The Yale study) assumes farmers are smart; that they will adapt before the climate change," he said.
In support of President Bush's decision to abandon the Kyoto Treaty, which would limit carbon dioxide emissions, he said the problem lies in developing countries, not the United States and Europe.
He said countries such as India, China and Mexico would dominate increased trends in carbon dioxide production.
"The Kyoto Treaty is completely ineffective - it only involves a small decrease in emission from a small fraction of the world's developed countries," he said. "By 2050 it would result in a 1/20 degree temperature lowering - that's absolutely negligible. We would need 10 or 20 Kyoto's to make an impact.
"I believe the human effect is there, but it's being washed out by natural processes."
