Tibet is warming at twice global average

NewScientist.com news service
Phil McKenna

The Tibetan plateau is heating up by 0.3°C each decade, more than twice the worldwide average, according to a new study from the Tibet Meteorological Bureau.

The findings, reported by the official Chinese news agency Xinhua, underscore a growing understanding that high elevations in tropical regions are experiencing dramatic temperature increases similar to those seen at the poles.

"Whether you are in the Himalayas, the Andes, or Africa, the temperature is rising highest at the highest elevations," says Lonnie Thompson, a glaciologist at the Ohio State University (See Interview: The Ice Man cometh). "They are seeing an acceleration in temperature rise that is very consistent with the high-elevation glacial retreat we are seeing."

Over the last 50 years, temperatures in the Arctic and Antarctica have risen by 0.2°C and approximately 0.5°C per decade, respectively, according to data from the Intergovernmental Panel on Climate Change.

Warming waters
The reason surface temperatures at the poles are warming so quickly is because the seawater temperature around them has risen faster there than anywhere else on Earth.

In the tropics, warming waters also play a role. When the already warm tropical waters heat up further, due to global warming, they evaporate even more moisture, which rises straight to the upper atmosphere.

"That is latent heat that is rising from the sea and released back to the atmosphere in the mid to upper troposphere," says Thompson. "And that's where the Tibetan plateau weather stations are located."

In 2000, researchers published a study looking at temperature changes on the Tibetan plateau since the 1950s. They found that temperature was not only increasing with time, but also with elevation across the plateau, concluding the data suggests the plateau is "one of the most sensitive areas" in the world in its response to global climate change.

A study published in 2006 in Science found similar increases in air temperature at high-elevation weather stations in the Andes.

Previous studies have found that all glaciers in the central and eastern Himalayas could disappear by 2035 at their present rate of decline. The melting glaciers threaten to unleash massive flooding followed by severe droughts across South Asia.