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Air over Antarctica is Warming, British Scientists Say

MELISSA BLOCK, host:

From NPR News, this is ALL THINGS CONSIDERED. I'm Melissa Block.

I'm Melissa Block.

MICHELE NORRIS, host:

And I'm Michele Norris.

Scientists studying air temperature over Antarctica are making a startling claim today. They say the air over that frozen continent has heated up faster than anywhere else on earth over the past 30 years. If it's true, the finding would challenge some basic understandings about how the earth's climate is behaving. That's if it's true.

Here's NPR's Richard Harris.

RICHARD HARRIS reporting:

All sorts of scientific outposts are dotted around Antarctica. Some researchers even brave brutal conditions to gather data throughout the year.

John Turner, from the British Antarctic Survey, says the most important data include air temperature readings as measured by weather balloons.

Mr. JOHN TURNER (British Antarctic Survey): But a lot of this data was just in hardcopy form. It was just written down and, especially all the Russian data, it was very difficult to access. So we had a big project working with the Russians to get the data digitized and getting it into a computer form.

HARRIS: Turner and his colleagues put together temperature records from nine different research stations run by five different countries, and their analysis of air temperature measurements taken a few miles over Antarctica, gives an astounding result.

Mr. TURNER: The whole world is warming at a rate of about, maybe a quarter of a degree a decade. But it's three times larger in the Antarctic.

HARRIS: So that suggests a difference of four degrees Fahrenheit since the 1970's. The result is surprising for a number of reasons. First, temperatures on the ground for most of Antarctica have not been climbing over these recent decades. Turner also looked at the computer models of the earth's atmosphere to see what they had to say about air temperatures over Antarctica.

Mr. TURNER: They don't show this warming. That could either be because the warming we see is being caused by a process which isn't represented in those models, or it could be because what we're seeing is natural climate variability. So the jury's out at the moment on what's causing this.

HARRIS: Again, the ground, well the ice in most of Antarctica, hasn't warmed up. So Dan Kirk-Davidoff, at the University of Maryland, says if the air above the ground is warmer, it must be blowing in from other parts of the globe. He says that would probably be the result of an unusual weather pattern, not a long-term change to the Antarctic climate.

Mr. DAN KIRK-DAVIDOFF (University of Maryland): Just like the weather changes from one day to the next, decades are a little bit different from one decade to the next. And when you look at climate models, this kind of variability is large, but not completely outside of the realm of things that happen.

HARRIS: If that's the case, it shouldn't be surprising to see a cooling trend in future decades. But other climate scientists suspect that the data are just plain wrong for some reason. Steven Sherwood from Yale University says he's quite skeptical that there's been a dramatic warming trend.

Mr. STEVEN SHERWOOD (Yale University): If that were the case, you should be able to look at the satellite records that we have and see similarly sort of hot spot over the South Pole. But it doesn't show that. In fact it shows that the South Pole is about the only place that doesn't seem to be warming.

HARRIS: Other scientists have also analyzed weather balloon data from Antarctica, and nobody before now has seen a dramatic warming trend. But assuming the new finding holds up to the scrutiny that has already begun, what does it mean?

Dan Kirk-Davidoff says it's not a near-term threat to the vast volumes of ice locked up in Antarctica.

Mr. KIRK-DAVIDOFF: We don't worry so much about the core part of Antarctic ice melting, because it's just so cold there. The average temperatures in the South Pole are many degrees below zero, so warming things up a little bit mostly has the effect of adding a little bit more snowfall and maybe adding a bit of ice to the core of Antarctica. If we're going to worry about ice melting in Antarctica, it's more around the edges, where warming sea surface temperatures would tend to interact with the ice that's right near the surface. And we do worry about increasing ice in those situations, and we've seen these big rafts of ice breaking off from the Antarctic Peninsula.

HARRIS: And the temperature of seawater is a very different story, not closely linked to air temperatures high over Antarctica. So the biggest issue for climate scientists really is having an observation that doesn't fit neatly into the world as they think they understand it.

Richard Harris, NPR News. Transcript provided by NPR, Copyright NPR.

Award-winning journalist Richard Harris has reported on a wide range of topics in science, medicine and the environment since he joined NPR in 1986. In early 2014, his focus shifted from an emphasis on climate change and the environment to biomedical research.