BOULDER, Colo., Oct. 22 (UPI) — A U.S. study of a 200,000-year-old sediment core from an arctic lake indicates ongoing biological and chemical changes are likely caused by human activities.
The University of Colorado-Boulder-led study shows that while environmental changes at the Baffin Island lake during the past millennia have been tightly linked with natural causes of climate change — like periodic wobbles in the Earth’s orbit — changes seen in the sediment cores since about 1950 indicate expected climate cooling is being overridden by results of human activity, such as greenhouse gas emissions.
“The past few decades have been unique in the past 200,000 years in terms of the changes we see in the biology and chemistry recorded in the cores,” said lead study Yarrow Axford of the university’s Institute of Arctic and Alpine Research. “We see clear evidence for warming in one of the most remote places on Earth at a time when the arctic should be cooling because of natural processes.”
The study that included researchers from the State University of New York, the University at Buffalo, the University of Alberta, the University of Massachusetts and Queen’s University in Kingston, Ontario appears in the Proceedings of the National Academy of Sciences.
Copyright 2009 by United Press International