Arctic, Antarctic Melting May Raise Sea Levels Faster Than Expected

BOULDER, Colo., March 23 (AScribe Newswire) -- Ice sheets across both the Arctic and Antarctic could melt more quickly than expected this century, according to two studies that blend computer modeling with paleoclimate records. The studies, led by scientists at the National Center for Atmospheric Research (NCAR) and the University of Arizona, show that Arctic summers by 2100 may be as warm as they were nearly 130,000 years ago, when sea levels eventually rose up to 20 feet (6 meters) higher than today.

Bette Otto-Bliesner (NCAR) and Jonathan Overpeck (University of Arizona) report on their new work in two papers appearing in the March 24 issue of Science. The research was funded by the National Science Foundation, NCAR's primary sponsor. The study also involved researchers from the universities of Calgary and Colorado, the U.S. Geological Survey, and The Pennsylvania State University.

Otto-Bliesner and Overpeck base their findings on data from ancient coral reefs, ice cores, and other natural climate records, as well as output from the NCAR-based Community Climate System Model (CCSM), a powerful tool for simulating past, present, and future climates.

"Although the focus of our work is polar, the implications are global," says Otto-Bliesner. "These ice sheets have melted before and sea levels rose. The warmth needed isn't that much above present conditions."

The two studies show that greenhouse gas increases over the next century could warm the Arctic by 5-8 degrees Fahrenheit (3-5 degrees Celsius) in summertime. This is roughly as warm as it was 130,000 years ago, between the most recent ice age and the previous one. The warm Arctic summers during the last interglacial period were caused by changes in Earth's tilt and orbit. The CCSM accurately captured that warming, which is mirrored in data from paleoclimate records.

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