The darker, the warmer: the illustration shows that the western Antarctic has warmed up considerably in the last 50 years. Image: Eric Steig
Read aloud Global warming does not stop at the Antarctic. Above all, the West Antarctic, the South America and the Pacific-facing part of the continent, has warmed by 0.5 degrees Celsius in the past 50 years, report Eric Steig and colleagues. The researchers first included satellite data in a statistical analysis to get information about the interior of the continent. The few weather stations in the Antarctic had so far drawn a reassuring picture: On the Antarctic Peninsula, a projecting toward Tierra del Fuego land, recorded the meteorologists, although a strong warming. But the remaining stations, which are almost all on the coast, reported no temperature changes. So far, climate scientists have concluded that the interior of the Antarctic does not warm up or even cool down.

Steig and his colleagues are now coming to a different conclusion. Indeed, the temperatures in the eastern Antarctic, the largest part of the southern continent, actually drop slightly. But west of the Transantarctic Mountains, which once crosses the continent, the climate heated up significantly since 1957. The average temperature for the entire Antarctic has therefore increased slightly. "The overall picture is very complex, " says Steig. "The Antarctic does not warm up everywhere at the same rate. Some regions are getting colder for a long time, but the continent as a whole is warming up. "

So far, climate researchers have assumed that the ozone hole is responsible for the cooling of the Antarctic. Steig and his colleagues now conclude that warm seawater temperatures and altered ice cover are reversing this effect in the west of the continent. The ice sheet in West Antarctica, where temperatures are especially high, is considered to be relatively unstable as much of the base is below sea level. If the ice sheets dissipate, the sea level would rise by seven meters.

Eric Steig (University of Washington, Seattle): Nature, Vol. 457, p. 459 Ute Kehse advertisement


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