Glaciers in southwest China feel the brunt of climate change

In a study published Oct. 25, 2011, in IOP Publishing's Environmental Research Letters, scientists examined data from 111 weather stations across south-western China and have shown that temperature patterns were consistent with warming, at a statistically significant level, between 1961 and 2008.

Of the 111 stations examined, 77 per cent displayed statistically significant increases in annual temperature.

Collating a broad range of research on glaciers during this time period, the researchers, from the Chinese Academy of Sciences, identified three characteristics that were consistent with the increasing trend in temperature; drastic retreats were observed in the glacial regions, along with large losses of mass and an increase in the area of glacial lakes.

In the Pengqu basin of the Himalayas, for example, the 999 glaciers had a combined area loss of 131 km² between 1970 and 2001, whilst the Yalong glacier in the Gangrigabu Mountains retreated over 1500 meters from 1980 to 2001.

The implications of these changes are far more serious than simply altering the landscape; glaciers are an integral part of thousands of ecosystems and play a crucial role in sustaining human populations.

Continued widespread melting of glaciers, caused by increasing temperatures, could potentially lead to floods, mudflows and rock falls, affecting traffic, tourism and wider economic development.

South-western China has 23,488 glaciers, covering an area of 29,523 km² across the Himalayas and the Nyainqntanglha, Tanggula and Hengduan mountains.

As well as temperature, the researchers also investigated precipitation; however the results were less marked. Annual increasing precipitation is consistent with climate change and was observed in 53 per cent of the stations. A decrease in annual precipitation can also influence glacial retreat and this was observed in central regions of the Himalayas.

The lead author of this study, Dr Zongxing Li, said, "I think glacial loss is caused mainly by rises in temperature, especially in the high altitude regions. From the 14 weather stations above 4000 m, there was an annual mean temperature increase of 1.73 ^°C from 1961 to 2008.

"It is imperative we determine the relationship between climate change and glacier variations, particularly the role of precipitation, as the consequences of glacial retreat are far reaching."