Friday, 13 November 2009

The Tibetan Plateau

The Tibetan Plateau is a large elevated plateau in Asia, most of which is located in China. It has an average elevation of 4.5 kilometres and has a total area of 2.5 million square kilometres (four times the size of Texas), giving rise to the nickname "The roof of the world". It is the third largest frozen store of freshwater in the world, and is the source for 10 major rivers in Asia. Almost half (47 percent) of the world's population depends on rivers that originate here. Unfortunately, according to a 2007 IPCC report, the ice in these glaciers is melting faster than anywhere else in the world.

It is difficult to overstate the important of the glaciers in the Tibetan Plateau. When considering the significance of their status as the third largest store of ice in the world, it is important to remember that the largest store, in Antarctica, provides water for none of the world's population, and the second largest, in Greenland, provides water for only a small number of people. This means that the glaciers in Tibet are the single most important store of ice in the world, in terms of supplying water for human needs.

In the short term, the accelerated melting may provide additional flows of freshwater. However, according to a 2007 report by the IPCC, the glaciers could completely disappear by 2035. This leads to the double impact of flooding in the short term, with some villages having already been washed away, with dwindling supplies leading to shortages in the medium term.

China has the world's largest population, with roughly 1.3 billion people, and has often had difficulty trying to feed its people. Over a quarter of China's land is desert, and the country is suffering from increasing desertification. Currently, about 2500 square kilometres are being converted to desert every year, and the rate has been rapidly increasing over the past decades. This has also led to an increase in dust storms, which prevent travel by blocking roads and railways, and cause significant casualties. Around 50 years ago, these occurred only every eight years or so, but now happen annually.

In addition to desertification, which obviously limits where crops can be grown, many existing rivers in China have become unusable because of pollution, and other rivers have begun to run dry. China has a great need for freshwater, and these problems, along with a growing population, are just making this need more acute. In order to meet their demand, China has been building dams and redirecting water from the Tibetan Plateau, and has plans to increase this activity.

The Ganges, fed from the plateau, is one of the most important sources of water to India and Bangladesh, and is considered a holy river by many Hindus. Shortages of water have already affected millions in Bangladesh, which has led to a mass migration to northeast India. This has led to demographic changes in the area and an increase in ethnic conflict. China is currently planning to divert the Brahmaputra River, as well, which could impact many millions more. This is creating significant political tension between China and India.

Many other countries depend on rivers sourced from the plateau, and are impacted by water diversion, including Vietnam, Laos, Cambodia, Thailand, Pakistan, and others. There are already many people in these areas that do not have access to a safe supply of drinking water, or who do not have a sufficient supply for irrigation. Clearly, as water supplies diminish, contention over the remaining supplies will only increase. This has the potential to cause significant political instability in the region, as well as an increase in starvation.
Unfortunately, even if all carbon emissions were eliminated today, many of these problems could not be prevented. The carbon already in the atmosphere means we are committed to a certain level of warming, and a certain amount of melting. However, we still have time to try to reduce the impact and scope of the problem as much as possible. This another reason why a very strong agreement is needed at Copenhagen. The fact that it is too late to fix all the problems caused by global warming is not a reason to give up, but, if anything, it is a warning of how much worse it could get if we fail to prevent global warming from accelerating even more.

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