Climate Change Racing On Tibetan Plateau - 10% Of Permafrost Degraded In 10 Yrs, 4/5 Glaciers Shrink

[hatrack]

The Tibetan plateau gets a lot less attention than the Arctic or Antarctic, but after them it is Earth's largest store of ice. And the store is melting fast. In the past half-century, 82% of the plateau's glaciers have retreated. In the past decade, 10% of its permafrost has degraded. As the changes continue, or even accelerate, their effects will resonate far beyond the isolated plateau, changing the water supply for billions of people and altering the atmospheric circulation over half the planet.

The plateau's pivotal role is due almost entirely to its height. Being an average of 4 kilometres above sea level makes it peculiarly cold for its latitude — colder than anywhere else outside the polar regions. Lhasa, capital of the Tibet Autonomous Region, is by Tibetan standards relatively low-lying, at 3,650 metres — yet it is higher even than La Paz, Bolivia, the highest capital city of a country. Lhasa's year-round average temperature is 8 °C; at the same latitude Houston, Texas, has an average temperature of 21°C. The altitude makes Tibet cold, especially in winter; its snow and ice cover, by reflecting sunlight, make it colder still. The very bulk of the plateau affects how winds circulate above it, and its altitude also places the surface simply closer to the stratosphere than is normal.

The proximate cause of the changes now being felt on the plateau is a rise in temperature of up to 0.3 °C a decade that has been going on for fifty years — approximately three times the global warming rate. The questions are how much more change to expect in the future, and how severe the effects will be on the planet's climate as a whole. “Our understanding of global climate change would be incomplete without taking into consideration what's happening to the Tibetan plateau,” says Veerabhadran Ramanathan, an atmospheric scientist at the Scripps Institution of Oceanography in La Jolla, California.

EDIT

The melting glaciers are starting to leave behind dangerous glacial lakes, in which meltwater ponds behind a dam of debris left by the retreating ice tongue. Scientists have identified 34 such glacial lakes on the northern slopes of the Himalayas, and 20 outburst floods have been recorded in the past 50 years. The risk of floods, though, is but a short-term danger far exceeded by long-term issues with water supplies atop the plateau. Runoff from the region's mountains feeds the largest rivers across Southeast Asia, including the Yangtze, Yellow, Mekong, Ganges and Indus rivers. If glaciers continue to retreat and snowpack shrinks atop the plateau, the water supplies of billions of people will be in danger6.

EDIT

http://www.nature.com/news/2008/080723/full/454393a.html

[hogwyld]

1. So, what's going to happen

when 2+ BILLION people go on the move in search of water? And what's going to happen if someone else is already there?

[phantom power]

2. Nothing good.