September 9, 2011
Study Casts Doubts On Natural Gas’s Impact On Global Warming
Despite the reduced amount of carbon dioxide given off by the burning of natural gas, increasing use of it and decreasing our reliance on coal would do little to slow down global climate change, claims a new study set for publication in the journal Climatic Change Letters.
The research, led by Tom Wigley, a senior research associate at the National Center for Atmospheric Research (NCAR), "underscores...the complex and sometimes conflicting ways in which fossil fuel burning affects Earth's climate," the organization said in a September 8 press release.
According to the NCAR, while burning coal causes emissions that trap carbon dioxide, trapping heat and leading to warming, it also releases sulfates and other particles in very large amounts. Those particles cool the planet by blocking incoming sunlight. Furthermore, burning natural gas would release methane, described as "an especially potent greenhouse gas," into the atmosphere.
As part of his research, Wigley created computer simulations that included "a worldwide, partial shift from coal to natural gas." That shift, the NCAR press release noted, would "slightly accelerate" global warming through at least 2050 (provided no methane was leaked in the process) and possibly until 2140 (if there were "substantial" methane leaks). After that point, the average global temperature would begin to decrease, but only by a few tenths of a degree per year.
"Relying more on natural gas would reduce emissions of carbon dioxide, but it would do little to help solve the climate problem," Wigley, who also works as an adjunct professor at Australia's University of Adelaide, said in a statement. "It would be many decades before it would slow down global warming at all, and even then it would just be making a difference around the edges."
"Whatever the methane leakage rate, you can´t get away from the additional warming that will occur initially because, by not burning coal, you´re not having the cooling effect of sulfates and other particles," he added. "This particle effect is a double-edged sword because reducing them is a good thing in terms of lessening air pollution and acid rain. But the paradox is when we clean up these particles, it slows down efforts to reduce global warming."
The study, entitled " Coal to Gas: The Influence of Methane Leakage," will be published next month in the journal Climatic Change Letters.
Image 2: Shifting from coal to natural gas would have limited impacts on climate, new research indicates. If methane leaks from natural gas operations could be kept to 2.5% or less, the increase in global temperatures would be reduced by about 0.1 degree Celsius by 2100. The reduction in global temperatures would be more minor with higher methane leakage rates. (Courtesy Springer, modified by UCAR.)
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