|The Regional Impacts of Climate Change|
|Other reports in this collection|
18.104.22.168. Climate Change and Desertification
Desertification may occur in any area where the potential evapotranspiration is greater than 70% of the total precipitation-as is the case for parts of this region. It is feasible that desertification itself can exacerbate climate change. Changes in land-use practices can affect surface temperatures through boundary changes in vegetation cover, which lead to differences in albedo and thus to temperature differences (IPCC 1996, WG II, Chapters 3 and 4). It has been suggested that where these changes occur over large areas, they could affect global mean temperatures. The effect is mediated in the short term by surface soil moisture and in the longer term by changes in soil conditions and in carbon sequestration, which lead to changed emissions of N2O and methane. There are no specific data from this region to support or refute this possibility.
There also is a great deal of variation in assessments of the nature and severity of the desertification problem, mainly because of the lack of adequate data. Many large-scale studies have suggested that the annual rate of expansion of desertified lands in central Asia ranges from 0.5% to 0.7% of the arid zone. Approximately 570 million ha in the region are classified as arid land. Assuming a conservative rate of expansion of 0.5% per annum, 3 million ha of land are becoming desertified every year. Arid-land desertification could occur faster if human and livestock populations continue to increase and particularly if the resilience of arid regions is negatively affected by climate change. Some recent research, however, has not supported the expanding-desert hypothesis. During favorable or "wet" years, there is little evidence to suggest that the desertification front has expanded. The different views regarding the importance of human abuse versus adverse climatic conditions in causing desertification and the lack of agreement on the scale of the problem point to the need for a better understanding of the problem and, in particular, better and more comprehensive data on its nature and extent. There is little doubt that desertification is an important environmental problem that needs to be addressed urgently-and that climate change will have an impact on it (IPCC 1996, WG II, Chapter 4), with environmental and economic repercussions.
Some of the Middle Eastern countries recently have launched action plans to reduce the effects of desertification (UNEP, 1997), though the results of these actions remain to be seen. There also are many technical programs in the Middle East to assist in desertification problems (UNEP, 1997).
Seven of the 21 countries in the region are landlocked; the others have a total of 21,000 km of coastline, mainly on the Mediterranean Sea and the Gulf of Oman. Coastal zones in this region are not identified as significantly affected by sea-level changes (IPCC 1996, WG II, Chapter 12). The major pressures on them will be related to development rather than the direct result of climate change.
Part of the Mediterranean Sea, the northWestern part of the Gulf of Oman, the southern part of the Caspian Sea, and the coast of Karachi are classified as coastlines under high potential threat from development (WRI, 1996; McMichael et al., 1996). This development includes large cities (>100,000 people), major ports, roads, and pipelines-all of which contribute to pollution in coastal areas.
Many countries in the region are major oil producers. Oil production is mostly land-based and is not as vulnerable to the impacts of climate change as offshore oil production in other regions. Transportation of oil also is less likely to be affected than some higher-latitude areas, which are projected to experience an increase in storm activity and icebergs (IPCC 1996, WG II, Section 8.2). However, coastal oil production areas are likely to be affected by storm surges (IPCC 1996, WG II, Sections 8.3.1 and 9.3.1).
Coastal pollution is a major problem in some countries of the Middle East. Some countries (e.g., Syria, Lebanon) have integrated coastal management programs to overcome some of these problems (UNEP, 1997). Despite such programs, the Red Sea and the Kuwait/Oman areas sustain more oil pollution than anywhere else in the world. In addition, coastal zones of the Middle Eastern countries experience oil spills from ships and pipelines, as well as land-based pollution discharges (UNEP, 1997)-all of which lead to the deterioration of coastal areas.
Fishery industries are important in some countries (e.g., the Persian Gulf countries in the Middle East). Overfishing and marine pollution have led to a decrease in fish catches. The loss of mangroves and intertidal areas (e.g., from dredging/infilling) probably has added to the problem by affecting breeding grounds (UNEP, 1997).
Preliminary studies and estimates show that if climate change were to cause an increase in flow from the Volga river, the resulting rise in the level of the Caspian Sea would significantly increase the vulnerability of its coastal zone, requiring some adaptation measures (Golubtsov and Lee, 1995).
Other reports in this collection