Researchers sorting through muddy sediment at the bottom of 10 Pacific Northwest lakes conclude that droughts match natural regional warming for various periods over the past 2,000 years.
Scientists took cores from the lake bottoms that penetrated into the lake mud as much as 30 feet. They measured the sediments that contain limestone for two oxygen isotopes—Oxygen 16 and Oxygen 18. Oxygen 18, the heavier of the two, is known to be present in greater abundance during periods of drought.
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The team argues in a paper published in Geophysical Research Letters that tying long-ago droughts to protracted natural climate change may show us what can be expected as human-caused climate change warms the Earth.
“This work contributes to our understanding of how the climate system has worked in the past with the goal of improving our ability to predict future droughts,” says Mark Abbott, professor and chair of University of Pittsburgh’s department of geology and planetary science. “And this knowledge should give us a better idea of how often droughts might occur in the future as the climate system changes.”
He also notes that the United Nations Intergovernmental Panel on Climate Change recently released its 2014 report, which predicts dire consequences, including drought, as a consequence of rapidly advancing anthropogenic climate change.
Additional scientists from Northern Illinois University, Indiana University-Purdue University Indianapolis, Penn State, Kent State University, the University of Arkansas, and the US Geological Survey contributed to the study.
The National Science Foundation supported the work.
Source: University of Pittsburgh
