Antarctica's Atmosphere Warming Dramatically, Study Finds

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Snowfall records of the past three decades show no change, Turner said. "But measuring snowfall is hard. Measuring temperature is obviously easier," he added.

Scientists expect the warming to create a small increase in snowfall over Antarctica, as the warmer, moister air blows over the continent and is cooled to form snow.

This in turn could mitigate, to a small extent, sea-level rise by "locking up" meltwater in the form of snow.

Since the atmospheric warming is greatest three miles (five kilometers) up in the atmosphere, Turner said it is unlikely to result in extensive melting of ice on the surface. The continent's tallest mountains are 2.5 miles (4 kilometers) high.

Complex Signals

Turner and his colleagues are now trying to understand why the atmosphere warming is disconnected from surface temperatures.

One possibility, he said, is that the region is showing a greater than expected sensitivity to greenhouse gases in the winter.

Antarctica is dark during the winter months, which means there is no sunlight to heat the surface.

However, the heat that is on the surface continues to radiate into the atmosphere, where it is trapped by the blanket of greenhouse gases, Turner explained.

Alternatively, the warming may reflect a change in air circulation patterns, though data collected at Antarctic weather stations suggest this has not happened, he said.

Bromwich, of the Byrd Center, said the findings fit the emerging picture of Earth experiencing the effects of global warming, such as the widely reported melting in the Arctic.

(Read "Arctic Ice Levels at Record Low, May Keep Melting, Study Warns.")

"To understand what is happening to our world, we also need to understand what is happening in Antarctica," Bromwich said.

"This [research] deepens the mystery rather than solves it, but it shows us the direction we should be looking."

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