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White out! The great Xinjiang blizzards of 2010

XINJIANG was hit by four devastating blizzards and its worst cold spell in 60 years. But it isn't all a bad thing since the region is warming and the weather brought much-needed water to the arid land. Wei Wenshou reports.

Between January 17 and 20 this year, the northwestern Xinjiang Uygur Autonomous Region was hit by the strongest cold wave in 10 years, with temperatures in Altay Prefecture plummeting to minus 40 degrees Celsius. Could this be the effect of global climate change?

The truth is that the temperature and precipitation in Xinjiang are generally on the rise. When viewed within a period of 25 years, the situation in northern Xinjiang is actually quite normal.

Although overall temperatures in Xinjiang for 2009-2010 winter were around 0.5 degree Celsius lower than the same period in preceding years, the entire region is actually warming up.

The latest winter also saw record levels of precipitation in Xinjiang. Most stations in the north recorded figures in excess of 80 millimeters - more than one and a half times greater than the previous year - and there was even an all-time high of 153.7 millimeters in Altay's Fuyun County. Based on current trends, meteorologists predict that the precipitation will continue to increase.

One-off storm?

What about the rest of China? Is the climate also going awry?

There has been a remarkable warming trend in northern China in the last 50 years. The year 2009 was the fourth warmest year on record, and for the past 13 consecutive years the annual average temperature in China was higher than the long-term average.

In the last 50 years, precipitation in western China has increased by 15 to 50 percent, while eastern China tended to experience flooding in the south and droughts in the north.

Precipitation has increased by 5 to 10 percent in southern China, while dropping by 10 to 30 percent in northern and northeastern China. The drought that hit Yunnan Province this past spring was an extreme event.

As weather and climate processes are inherently complex, no scientist has yet been able to provide a clear explanation of such "abnormal" events within the context of global climate change.

Bright side

Xinjiang is located in the hinterland of the Eurasian continent, with the Altai Mountains to the north, the Tianshan Mountains in its middle and the Kunlun Mountains to the south. Encircled by these mountains are the vast Junggar and Tarim basins. Xinjiang lies far away from any ocean, and its mountains block any warm air masses from the sea, leading to arid and semi-arid climates.

With such a dry climate, it is no surprise that water is a precious resource in the region. Historically, human settlements were only able to flourish in oases; it is virtually impossible to live in the barren desert.

Xinjiang is home to some 570 rivers, most of which are short with small flow volumes. The majority are fed by melting glaciers from the mountains, and thus the flow fluctuates greatly with the seasons.

The freshwater resources available in Xinjiang - be it groundwater, surface rivers or glaciers in the mountains - have a direct influence on the ecosystem and human activities.

The glaciers in Xinjiang cover 40.7 percent of the total glacial area in China, and account for 42.7 percent of the total glacial volume in China. Every year, meltwater makes up 22.6 percent of the total river flow in Xinjiang, where the snow and ice cover of its mountains represent a vital solid reservoir.

In the last 50 years, temperatures have increased by 0.2 degree Celsius every 10 years in northwestern China. The height of the 0-degree isotherm has risen significantly since 1993. This has greatly affected the melting of the glaciers.

As the snow line is pushed upward, the volume of meltwater produced is also accelerated. The effects of a changing climate are far-reaching, and the impact on the water resources and ecological environment in Xinjiang is still not fully understood.

However, the abundant snow and increased precipitation is essential for irrigating crops and nourishing the fragile ecosystem in the desert. It also helps in the accumulation of more snow in the mountains. Viewed from this perspective, the recent blizzards could do Xinjiang more good than harm.




 

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