Some experts say the wind seems to be dying down across the United States, which could be a result of global warming, The Associated Press reported.
But while many scientists disagree on the idea that winds may be slowing at all, a revolutionary new study suggests that average and peak wind speeds, particularly in the Midwest and the East, have been noticeably slowing since 1973.
Eugene Takle, a professor of atmospheric science at Iowa State University and the study’s co-author, said in some places in the Midwest, the trend shows a 10 percent drop or more over a decade.
The study’s lead author, Sara Pryor, an atmospheric scientist at Indiana University, noted there has been a jump in the number of low or no wind days in the Midwest.
Pryor plotted out wind measurements on U.S. maps that show wind speeds falling mostly along and east of the Mississippi River. While other areas such as west Texas and parts of the Northern Plains do not show winds slowing nearly as much.
However, some of the biggest drops in wind speeds were noted in states such as Ohio, Indiana, Michigan, Illinois, Kansas, Virginia, Louisiana, Georgia, northern Maine and western Montana.
Pryor said the stations bordering the Great Lakes do seem to have experienced the greatest changes, likely because there’s less ice on the lakes and wind travels faster across ice than it does over water.
She acknowledged that the study is still in the preliminary stages and it’s still too early to know if this is a real trend or not. However, she suggests the study raises a new side effect of global warming that has yet to be explored.
According to Pryor, whose study will be published in August in the peer-reviewed Journal of Geophysical Research, the ambiguity of the results is due to changes in wind-measuring instruments over the years. She said that while actual measurements found diminished winds, some climate computer models – which are not direct observations – did not.
Both Pryor and Takle said a couple of earlier studies also found wind reductions in Australia and Europe, offering more comfort that the U.S. findings are legitimate.
Takle also noted that the research makes sense based on how weather and climate work: In global warming, the poles warm more and faster than the rest of the globe, and temperature records, especially in the Arctic, show this””meaning the temperature difference between the poles and the equator shrinks and with it the difference in air pressure in the two regions. Differences in barometric pressure are a main driver in strong winds. Lower pressure difference means less wind.
The authors agree that information alone doesn’t provide the definitive proof that science requires to connect reduced wind speeds to global warming.
There is a rigorous and specific method in climate change science that looks at all possible causes and charts their specific effects to attribute an effect to global warming. Scientists say that should eventually be done with wind.
But other experts in the field, like Jeff Freedman, an atmospheric scientist with AWS Truewind, an Albany, N.Y. renewable energy consulting firm, said his research has found no definitive trend of reduced surface wind speed.
Pryor agreed that changing conditions near wind-measuring devices can skew data, and if trees grow or buildings are erected near wind gauges, that could reduce speed measurements.
But many outside experts agree there are signs that wind speed is decreasing and that global warming is the likely cause.
Michael Mann, director of the Earth System Science Center at Penn State University, said the new study demonstrates, rather conclusively, that average and peak wind speeds have decreased over the U.S. in recent decades.
However, the study’s results conflict with climate models that show no effect from global warming, according to naysayer Gavin Schmidt, a NASA climate scientist in New York. He believes any decline in the winds that might be occurring won’t have much of an effect on wind power.
But a 10 percent reduction in wind speeds over a decade would have an enormous effect on power production, according to another expert, Jonathan Miles of James Madison University.
Pryor said it would be premature to modify wind energy development plans at this point, but she believes a 10 percent change in peak winds would translate into a 30 percent change in how much energy is reaped.
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