In order to understand the issues of climate change in Central Asia, one has to understand the nature of water distribution in the region. First of all, Asia is a large continent, with less shoreline per land mass than other continents. This has profound effects on its ability to obtain water, particularly in the Central regions. The map below shows relative water scarcity across Eurasia and Africa:
The pale area shows regions of relative water scarcity; the Northeastern portion of this pale area covers the Central Asian region, from the east side of the Caspian into Mongolia and China's Xinjiang province. This relatively arid terrain has both mountains and deserts. The mountains of Kyrgyzstan and Tajikistan hold glaciers, which feed the two river systems of Central Asia, the Amu Darya and Syr Darya (Darya=river), both of which feed the Aral Sea. The Amu and Syr Darya watersheds are called exotic watersheds, because they descend from a water-rich upstream to a water-poor downstream. The 680-mile long (1100 km) Kara-Kum canal through Turkmenistan, though not a river, diverts sufficient water from the Amu Darya to be included as part of the water resources of Central Asia.
A slightly larger picture of Central Asian water systems uses the Aral Sea Basin as a system. The Aral Sea, between Kazakhstan and Uzbekistan, is also fed by water from Iran and Afghanistan. Watershed initiatives between Central Asian states have thus far tended to exclude these minor contributors. As water becomes scarce, this may no longer be possible.
A third way of looking at watersheds in Central Asia includes mountain precipitation, geology, and geography. At the western limit of the mountain ranges, precipitation averages 1500 mm per year (60 inches) ; at the east, 150 mm per year (6 inches). The Pamir and Tien Shan mountain ranges hold approximately 20,000 glaciers. These mountain ranges are seismically active, and earthquakes such as the one this week are not uncommon. (See previous post). In 1911, an earthquake in the Pamirs created a naturally-formed dam and 
new lake in Tajikistan, the 61-km long Lake Sarez, pictured here. But just as earthquakes can make dams, they can destroy them, leaving Central Asia liable to flooding, mudslides, and redefinition of watercourses. Likewise, global warming presents the prospect of increased seismic activity. It also suggests that glaciers will melt at a faster rate, meaning that water runoff from glaciers is liable to create floods at first, and then severely curtail these water sources for Central Asia's people in the future.
At the same time, rainfall patterns are expected to change: boreal Asia (e.g., Siberia) is expected to gain waterfall, while arid sections of Asia are expected to have less rainfall.
Looking at climate change with respect to Central Asia underscores many of the statements made on the news. First and foremost, regions that will be most affected by global warming are regions already in some water distress. Second, Central Asian states do not have sufficient development in water infrastructure already. The politics of water distribution in exotic watersheds such as Central Asia do not lend themselves to easy political or economic answers for development. Furthermore, a system that is patched together for today may well not answer in the floods, earthquakes, and human distress of tomorrow.
Upcoming:
Central Asian water issues are fundamental to understanding the political and economic challenges in this region–check back for more on Central Asian Hydropolitics.
Also, the Aral Sea, one of the world's largest environmental disasters, represents a worst-case future for Central Asia as a whole. Check back for an Aral Sea update next week.
Biodiversity Hotspots.org Central Asia page for rainfall and mountain information;
Aral Sea Basin information from Oregon State University's Transboundary Freshwater Dispute Database .
UNEP/GRID-Arendal climate change group-its 2001 report,
the Central Asia pages
Great book on Central Asian water issues: Phillip Micklin's Managing Water in Central Asia (see Worth Reading page-Central Asia).
My colleague Bill Hewitt, who has a lot of experience in climate change issue advocacy, is writing for FPA Climate Change blog; he has links to other blogs and newsources on this vital issue.
Maps: United Nations University; University of Indiana, Bloomington
Photo: NASA Earth Observatory
