Expanding Antarctic sea ice linked to natural variability

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The recent trend of increasing Antarctic sea ice extent -- seemingly at odds with climate model projections -- can largely be explained by a natural climate fluctuation, according to a new study led by the National Center for Atmospheric Research (NCAR).

The study offers evidence that the negative phase of the Interdecadal Pacific Oscillation (IPO), which is characterized by cooler-than-average sea surface temperatures in the tropical eastern Pacific, has created favorable conditions for additional Antarctic sea ice growth since 2000.

The findings, published in the journal Nature Geoscience, may resolve a longstanding mystery: Why is Antarctic sea ice expanding when climate change is causing the world to warm?

The recent trend of increasing Antarctic sea ice extent -- seemingly at odds with climate model projections -- can largely be explained by a natural climate fluctuation, according to a new study led by the National Center for Atmospheric Research (NCAR).

The study offers evidence that the negative phase of the Interdecadal Pacific Oscillation (IPO), which is characterized by cooler-than-average sea surface temperatures in the tropical eastern Pacific, has created favorable conditions for additional Antarctic sea ice growth since 2000.

The findings, published in the journal Nature Geoscience, may resolve a longstanding mystery: Why is Antarctic sea ice expanding when climate change is causing the world to warm?

The study's authors also suggest that sea ice may begin to shrink as the IPO switches to a positive phase.

"The climate we experience during any given decade is some combination of naturally occurring variability and the planet's response to increasing greenhouse gases," said NCAR scientist Gerald Meehl, lead author of the study. "It's never all one or the other, but the combination, that is important to understand."

Study co-authors include Julie Arblaster of NCAR and Monash University in Australia, Cecilia Bitz of the University of Washington, Christine Chung of the Australian Bureau of Meteorology, and NCAR scientist Haiyan Teng. The study was funded by the U.S. Department of Energy and by the National Science Foundation, which sponsors NCAR.

Read more at ScienceDaily

Image: Antarctic sea ice via NASA