David S. Chapman, a University of Utah geologist who has taken the Earth's temperature and discovered a record of climatic changes, says global warming is here and it's bound to get worse before it improves.
"I think it's very clear to everyone who looks at this that the Earth's warming," said Chapman, a geology professor and interim dean of the Graduate School. He spoke Wednesday in the Gould Lecture series, held yearly in the U.'s Marriott Library.
The talk drew hundreds of students and faculty. They filled the lecture hall and stood in the rear and entrances.
Chapman and his students drilled bore holes in Utah, where they discovered that temperature fluctuations left a record in the ground. Studying bore holes worldwide, he can trace warming and cooling episodes on Earth's surface over the past 400 years.
This century, the average air temperature has gone up one degree, amounting to a small and gradual, but significant, change.
Greenhouse gases released by burning fossil fuel are widely blamed for the changes. Chapman said he thinks the evidence for that is "reasonable but not conclusive." Further studies could improve our understanding, he said.
Regardless of the cause, Chapman said, "We're now in a different ball game from where we've been in the last, probably, million years" in terms of climatic change.
Other evidence of global warming is found in bore holes in Antarctic ice, where air bubbles preserve a record of atmospheric contents reaching to 245,000 years ago.
Greenhouse gases in the atmosphere, like carbon dioxide and methane, fluctuate over time. But never before have they shot up as they have this century. In 100 years, concentrations of some greenhouse gases have gone up at least 100 percent.
Global warming will mean that agriculture will shift, because particular plant communities depend on climate. In 2050, if the trend continues, St. George residents may have to contend with malarial mosquitoes because with hotter weather these insects will migrate north.
As the ice sheets melt and ocean water expands because of warmer temperatures, sea levels will rise. That will cause terrible problems for residents of low-lying atolls in the Pacific.
While all this is going on, the Earth's population will increase, he said. People from developing countries will want to improve their lifestyles, which seems to mean using more fossil fuel. That would add to the greenhouse problem, unless they have an alternative way to improve their standard of living.
Chapman called for developed countries to improve energy conservation and efficiency. If the world relies more on renewable, nonpolluting energy like wind and solar power, that would reduce polluting emissions.
Perhaps developing countries can skip the stage of industrialization and go directly into use of better sources of energy. In that case, Chapman said, global warming might be serving as a "smoke alarm" that will result in improvements.
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