Connecting Arctic Sea Ice and Tibetan Plateau Snow Cover
07 Jun 2006 - Articles, Water & Oceans, Ice & Snow, Arctic
View of the Tibetan plateau
© FAO / FAO
Rising global temperatures are melting glaciers on the Tibetan Plateau at an increasingly rapid rate. This may have caused many serious flooding occurrences in the past decade and could contribute to future serious water shortages (and other ecological problems). In response to this growing problem, the Polar Research Institute of China (PRIC) is to launch a major scientific program to study possible associations between Polar climate systems and the Tibetan Plateau and broader East Asian climate.
Roof of the world:
About 55 million years ago, after breaking up from the super-continent of Gondwana and drifting North, India collided directly into the Eurasian tectonic plate. The resulting uplift created the Tibetan Plateau, sometimes also referred to as the 'roof of the world': an immense upland, some 3500 by 1500 kilometers in size, that averages more than 5000 meters in elevation and includes almost all of the world's territory higher than 4000 meters.
Tibet plateau - satellite view
© NASA / NASA
The Tibetan Plateau contains not just Mount Everest and all 13 other peaks higher than 8000 meters, but hundreds of 7000-meter peaks each higher than anywhere else on Earth. Beneath it, the Earth's continental crust is also at its thickest, reaching 100 kilometres in some areas. Today, the Indian plate continues to move Northward at around 150 millimeters per year, making it the fastest moving plate on Earth.
The Plateau is also home to over 46,000 glaciers covering nearly 60,000 square kilometres of the region - a smaller version of the snow and ice-locked Polar Regions. The glaciers' melt-water is the source of many major Asian rivers, including the Yangtze, the Huang He (or Yellow) River, the Indus, the Ganges, the Mekong and the Irrawaddy.
Warming temperatures:
According to the Chinese Academy of Meteorological Sciences (CAMS), the 2003 average temperature of the Plateau, was a whole degree centigrade higher than the average temperature of the previous 30 years. Snow accumulation has been rapidly declining in recent years, with a snowfall of only 9 centimeters in 2004, down from a peak of 70 centimeters in 1994.
According to the Academy, the Plateau's glaciers have been melting at a rate of 7% annually since 2000, as warming trends have accelerated. If, as expected, the rate of melt continues at this high figure, glacial coverage of the Plateau will be reduced by 50% over the next ten years.
Glaciers serve as regulators of regional ecosystems, storing up snow and ice in the winter months when precipitation is at its peak, then releasing it during the drier summer as melting occurs. Any decrease in glacial volume will have a direct negative impact, with more serious droughts in summer as a result of reduced melt-water, and more floods in winter as less water is retained as ice.
As an indication of the potential human cost of this change, the Independent newspaper in the UK recently published figures stating that in China alone, 300 million people depend on water from the Plateau glaciers for their survival, that already 400 cities are short of water, and that for 100 of them (including Beijing) the shortages are becoming critical.
Rising temperatures across the region are starting to thaw out the Plateau's tundra, turning it into a desert, triggering more droughts and increasing the frequency and extent of sandstorms. Already in the first half of 2006, 13 sandstorms have hit Northern China and one in particular dumped over 330,000 tons of dust on Beijing, causing dangerous air pollution and forcing the authorities to consider a system of "dust forecast".
Science searches for connections:
Responding to the alarming changes occurring on the Tibetan Plateau, PRIC and CAMS, are launching, during the International Polar Year (IPY) 2007-2008, an integrated research program to study how Polar sea-ice and atmosphere interactions link with Plateau temperatures, snow cover and the broader East Asian climate.
Previous Chinese research by PRIC's Dr Zanhai Zhang and others has investigated such possible linkages. It suggests that linked variations in Plateau snow cover, and Arctic sea-ice, particularly in the Barents Sea, have important impacts on summer rainfall in China. The next phase of research will seek to improve scientists' understanding of the mechanisms and processes at work, especially where they relate to sea ice variability and atmospheric processes.
Although led by PRIC, the research will be carried out in collaboration with the International Arctic Research Centre (IARC), the Australian Antarctic Division (ANARE), the Finnish Institute of Marine Research (FIMR) and the Japan National Institute of Polar Research (JNIPR). As part of the programme, the Chinese polar research vessel, Xuelong, will be deployed to both the Arctic and the Antarctic, and an array of automatic weather stations will be deployed on the Plateau.
By: Jean de Pomereu
