Deserts of the Future - A View From Moscow

Deserts of the Future - A View From Moscow

-Stephen Shenfield, The Moscow Times: May 23, 2001

In a previous article for The Moscow Times, I considered the long-term impact of global warming in Russia's Far North. In the north, the permafrost will melt and be transformed into a sea of mud. The long-term impact of global warming in the southern parts of the formerly Soviet region promises to be no less catastrophic.

Let us start with the steppe zone of southern Russia, Ukraine and northern Kazakhstan. This zone already suffers badly from lack of moisture, which exacerbates the erosion and salinization of the soil. Thus of Kazakhstan's 35 million hectares of arable land, 18 million are already dangerously eroded and 8 million are saline. In the worst affected areas, such as the republic of Kalmykia, desertification is far advanced. Lack of moisture is even more acute in central and western Kazakhstan and in Uzbekistan and Turkmenistan, where 3 million to four million hectares are lost to the desert each year. Historically, these processes have been primarily due to extremely poor management of land and water resources - inefficient irrigation, deforestation, overgrazing, the tilling of marginal land and so on. However, climate change is already making matters much worse and will continue to do so in the future.

Global warming, by definition, means higher temperatures. The hot and dry summer of 1999 - when in southern Russia temperatures topped 40 degrees Celsius - that wreaked havoc on the harvest was a harbinger of things to come. But heat is not the only problem. Even more serious is drought. In 2000, Karakalpakstan and Mongolia suffered their most devastating droughts in living memory. Global warming in the former Soviet Union is accompanied by a redistribution of precipitation: The south gets drier and the north gets wetter.

That, of course, is a general tendency. Water will not be receding everywhere in the south. The Caspian Sea is a major exception to the overall pattern. Nobody understands just what makes the Caspian tick. Until recently, the level of the sea was rising, threatening to flood low-lying coastal areas, especially in Turkmenistan. Scientists cannot exclude the possibility that this tendency may resume and worsen. The Caspian thus stands in sharp contrast to its neighbor to the east, the Aral Sea, which is fast drying up - a fate that also awaits other inland water bodies of the south, such as Lake Balkhash in eastern Kazakhstan and Armenia's Lake Sevan. The Caspian is protected from desiccation by the Volga River, which empties into it water originating in areas of higher precipitation to the north.

Nevertheless, almost all of Central Asia's water comes not from the north or west, but from the east and south-east - from the rain, snow and ice of the high mountains of Kyrgyzstan, Tajikistan, Afghanistan, Xinjiang and southeastern Kazakhstan. The mountain waters flow through tributaries to the great twin rivers, the Amu Darya and the Syr Darya, and these rivers in turn - or what little is left of them after evaporation and cotton and rice irrigation have taken their toll - feed the Aral.

How does global warming affect this hydrological system? It might be expected that the flow of water would progressively decrease, but that is not what has been happening. On the contrary, the 1990s saw a rate of flow well above the average for the preceding three decades. We can resolve the paradox if we look closely at what is going on up in the mountains. According to observations taken by Kyrgyz meteorologists in the Alatau range of the Tien Shan (Mountains of Heaven), the flow in those rivers that are fed by summer rain and the melting of winter snow has decreased significantly in recent decades, but this effect has been more than compensated for by increased flow in those rivers that are fed by runoff from glaciers. Thus average summer temperatures have risen and year-round precipitation has decreased, while ice melt has accelerated. And the glaciers are shrinking accordingly: The area covered by them is steadily contracting, and they are increasingly restricted to the highest altitudes.

As the glaciers go on melting, the total flow from the mountains into the rivers of the Aral Sea basin will remain high. It may even rise further, and places downstream from big glaciers may find themselves in peril from summer flooding. But eventually, certainly by mid-century, the mountains will be bare and the glaciers will be gone. Then Central Asia will face the drought to end all droughts - for it is by no means clear what, if anything, can bring it to an end.

So in the south as in the Far North, the worst effect of global warming is that it makes the ice - the ice of the permafrost and the ice of the glaciers - melt. We never realized it, but as it turns out we can't get on without ice. Is there anything that can be done to avert this future? In view of the inertia inherent in global warming, it may already be too late. More detailed calculations are needed to judge that. Perhaps sufficiently radical action at the global level would make a difference. With George W. Bush in the White House, the question seems simply rhetorical.