State of the Planet

News from the Columbia Climate School


Shriveling Rivers

The ramifications of climate change are often discussed in terms of rising sea levels, atmospheric changes, desertification, and worsening, more frequent natural disasters. Another impact of climate change could have immediate and disastrous effects on water availability both here in the US and abroad. Recent research increasingly suggests that the world’s major rivers are essentially drying up. In China, where water resources are already incredibly scarce, the Yellow River is overtaxed by agricultural use, not to mention the effects of climate change.

Researchers from the National Center for Atmospheric Research analyzed data on water supply between 1948 and 2004 in 925 rivers, and used computer models to assess flows and predict future changes. They found that many of the world’s major rivers (about 1/3) have registered flow changes and are essentially drying up, and while this can partly be attributed to dam construction and agricultural use, it is also very clearly linked to climate change, which is altering rainfall patterns and increasing evaporation due to higher temperatures.

India’s Ganges has already been affected, as has the Colorado River in the US. This should have major impacts on water planning, which typically assumes that flows for the next century will match those of the last century. While researchers found that flow change is generally gradual, the problem will be much compounded in drought years. Researchers from the Scripps Institution of Oceanography have determined that scheduled deliveries from the Colorado River will be missed 60-90 percent of the time by the middle of this century.

Of course, it should be noted that climate change can also have the opposite effect on rivers. The Yangtzee River’s flow, for example, has been sustained by melting Himalayan glaciers. This effect can be compared to a bandaid on a big wound; once the glaciers are gone, detrimental effects on the rivers will eventually be compounded.

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Dan Stellar
15 years ago

This really shows how the effects of climate change go far beyond generally warming temperatures. The intersection of climate and water is a very important, and still poorly understood, area. As this post points out, the world’s major rivers are already massively overstressed, just from human use. When climate change further aggravates the situation, the results may well be disastrous.