Siberian Winters See Temp Uptick

时间 : 2015-02-11 09:50来源 : VOA官网 收听下载次数 :
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The old-timers are right: Siberia is just not as cold as it used to be. In fact, wintertime temperatures in the vast, frigid region have been rising for the last 7,000 years.

That's according to new research from the Alfred Wegener Institute in Germany. Russian and German researchers studied ice wedges, a kind of underground glacier formed by long cycles of freezing and thawing. Ice cores taken from such a wedge can reveal winter temperatures over years, decades, centuries and even millennia. The research is in the journal Nature Geoscience. [Hanno Meyer, Long-term winter warming trend in the Siberian Arctic during the mid- to late Holocene]

The data are not precise enough to say exactly how much Siberia has warmed, only that it has definitely heated up. The ice wedge record from the Lena River Delta also shows that the winter temperature rise accelerated around 1850—in keeping with the worldwide warming trend due to greenhouse gas emissions from fossil fuel burning.

The research team will probe ice wedges in other parts of the tundra to confirm their finding.

The new information does not mean that residents of Oymyakon, the coldest town on Earth, will get a reprieve from wintertime temperatures that plunge as low as minus 68 degrees Celsius. But thawing permafrost will mean the release of not just frozen mammoths but also more methane and carbon dioxide, further exacerbating global warming. And accelerating climate change means that newly appearing mysterious craters in Russia and other signs of the permafrost meltdown are just the beginning of Arctic surprises.

—David Biello