The Regional Impacts of Climate Change


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7.3.2. Ecosystems

  • The region is characterized by arid and semi-arid lands, on which it depends for much of its economic activity (e.g., agriculture and livestock grazing in rangelands). These ecosystems are under extreme pressure from human activities and current climatic conditions (e.g., high temperatures and prolonged droughts). Because of the current marginality of soil-water and nutrient reserves, some ecosystems in semi-arid regions may be among the first to show the effects of climate change. However, a number of management options (e.g., better stock management, more-integrated agroecosystems) could improve land conditions.
  • The relatively hospitable mountain regions are under particular pressure from human settlements and commercial cultivation, which have led to land degradation and adverse effects on water supply. Glacial melt is forecast to increase under climate change, which would lead to increased summer flows in some river systems for a few decades, followed by a reduction in flow as the glaciers disappear.
  • A tenth of the world's known species of higher plants and animals occurs in this region. Some countries (particularly Turkey and Tajikistan) are centers of origin for many crop and fruit-tree species; as such, they are important sources of genes for the wild relatives. Few studies are available to assess the impact of climate change on the biodiversity of the region; given its importance, however, there is a need for such studies. Biodiversity is being lost in the region because of human activities, especially land degradation and the overuse of resources.

7.3.2.1. Grasslands, Rangelands, Woodlands, and Deserts

Half of the region (see Table 7-1) is classified as arid land, much of which is true desert (i.e., extremely arid, as defined in IPCC 1996, WG II, Chapter 3). Another tenth of the region is classified as semi-arid rangeland, dominated by grasslands or shrublands. About 10% of the arid and semi-arid land is classified as having some soil constraints, indicating either that it shows significant soil degradation or that it is desertified (see Table 7-1). The region's major deserts and some of their characteristics are listed in Table 7-2, along with their classification (i.e., semi-arid, arid, or extremely arid, as defined in IPCC 1996, WG II, Chapter 3). For comparative purposes, deserts in adjoining regions (e.g., the Gobi desert from the Temperate Asia region) are included. Deserts are classified as cold deserts (e.g., upland deserts of Middle Asia that are 1,200 m above sea level) or hot deserts (e.g., those in the Middle East). The seasonality of the deserts' rainfall varies; some receive predominantly winter rain, whereas others receive mostly summer rain. Deserts with very sporadic rain events are classified as aseasonal.


Table 7-2: Geophysical characteristics of deserts in the Middle East and Arid Asia region.

Desert (Country) Aridity Main Rainy Season Temperature of Coldest Month/ Absolute Min (C) Temperature of Warmest Month/ Absolute Max (C) Latitude Elevation (m) Precipitation (mm/yr) Area (000s km2)

Arabian Desert Extreme Arid/ Aseasonal 0-10/10-20/ 20-0/>30 15-31N 0-1,200 25-150 800
(includes Rub al Khali and Nafud) Arid/Semi-Arid Winter 20-30
 
Iranian Desert Extreme Arid Winter 0-10/-10 20-30/+45 27-36N 200-800 50-100 135
(includes Dasht-i-Margo, Dasht-e-Naomid, Dasht-e-Kavir, Dasht-e-Lut) Semi-Arid/Arid
 
Negev (Israel) Arid Winter 10-20 20-30/>30
 
Syria, Iraq, N. Arabian, Jordanian Deserts Arid Winter 0-10/-11 20-0/+470 31-37N 200-800 100-150
 
Registan (Afghanistan) Extreme Arid Winter /-19 /+42 29-32N 500-1,500 50-100 40
 
Middle Asia (1) and Kazakstan
Garagum Extreme Arid/Arid Biseasonal/Spring -5-10/-35 +27 +30/+ 50 37-42N 100-500 70-100 350
Ustjurt and Mangyshlak Arid/Semi-Arid Biseasonal/Spring -5-10/-40 +26+28/+42 42-45N 200-300 80-150 200
Qizilkum Extreme Arid/ Arid/Semi-Arid Biseasonal/ Spring -4-8/-32 +28+30/+45 42-44N 50-300 70-180 300
Priaralski Garagum Arid Biseasonal/Spring -11-14/-42 +26+28/+42 46-48N 400 130-200 35
Betpaqdala Arid Biseasonal/Spring -12-13/-38 +26+28/+43 44-46N 300-350 100-150 75
Mujunkum Arid/Semi-Arid Biseasonal -2-3/-45 +24+28/+40 43-44N 100-660 170-300 40
Moinkum Semi-Arid Biseasonal/Spring -7-11 +25+27 43-45N 300-700 250-300 80
Saryesik-Atyrau Arid Biseasonal -14-15 +23+25 45-46N 300-500 150-200
Bolshie and Malye Barsuki Arid Biseasonal/Spring -12-15 +25+27 46-48N 100-200 150-200 40
Naryn-Peski Semi-Arid Biseasonal -9-12 +23+25 46-50N 0-50 250 200
 
Others Adjacent to the Region
Gobi (China, Mongolia) (2) Semi-Arid/Extreme Arid Biseasonal /-40 /+45 42-47N 900-1,200 50-200 1050
Ordos (China, Mongolia) Arid/Semi-Arid Summer /-21 /+42 38-40N 1,100-1,500 150-300 95
Sinai (Egypt) Extreme Arid/Arid Aseasonal 10-20 20-30
Takla Makan (China) (2) Semi-Arid/Extreme Arid Biseasonal -10-20 /-27 /+37 36-43N 800-1,500 50-75 271
Thar (India, Pakistan) (2) Arid/Semi-Arid Summer/Aseasonal 10-20/-1 >30/+48 24-31N 0-800 150-500 300
Thal (Pakistan) Arid Summer /-2 /+49 30-32N 100-200 50-200 26

Sources: McGinnies et al., 1968; Wilson, 1976; Walter et al., 1983; Evenari et al., 1985; Babaev et al., 1986.

(1) Includes FSU.
(2) Not in this region.

 

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