The Regional Impacts of Climate Change

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Arid Western Asia (Middle East and Arid Asia)

This region includes the predominantly arid and semi-arid areas of the Middle East and central Asia. The region extends from Turkey in the west to Kazakstan in the east, and from Yemen in the south to Kazakstan in the north. The eastern part of the region has a large area dominated by mountains.

Ecosystems: Vegetation models project little change in most arid or desert vegetation types under climate change projections-i.e., most lands that are deserts are expected to remain deserts. Greater changes in the composition and distribution of vegetation types of semi-arid areas-for example, grasslands, rangelands, and woodlands-are anticipated. Small increases in precipitation are projected, but these increases are likely to be countered by increased temperature and evaporation. Improved water-use efficiency by some plants under elevated CO2 conditions may lead to some improvement in plant productivity and changes in ecosystem composition. Grasslands, livestock, and water resources are likely to be the most vulnerable to climate change in this region because they are located mostly in marginal areas. Appropriate land-use management, including urban planning, could reduce some of the pressures on land degradation. Management options, such as better stock management and more integrated agro-ecosystems, could improve land conditions and counteract pressures arising from climate change. The region is an important refuge for wild relatives of many important crop species; with appropriate conservation measures it may continue to provide a source of genetic material for future climatic conditions.

Hydrology and Water Resources: Water shortage, already a problem in many countries of this arid region, is unlikely to be reduced, and may be exacerbated, by climate change. Changes in cropping practices and improved irrigation practices could significantly improve the efficiency of water use in some countries. Glacial melt is projected to increase under climate change-leading to increased flows in some river systems for a few decades, followed by a reduction in flow as the glaciers disappear.

Food and Fiber Production: Land degradation problems and limited water supplies restrict present agricultural productivity and threaten the food security of some countries. There are few projections of the impacts of climate change on food and fiber production for the region. The adverse impacts that may result in the region are suggested by the results of studies that estimate that wheat production in Kazakstan and Pakistan would decline under selected scenarios of climate change. The studies, however, are too few to draw strong conclusions regarding agriculture across the entire region. Many of the options available to combat existing problems would contribute to reducing the anticipated impacts of climate change. Food and fiber production, concentrated on more intensively managed land, could lead to greater reliability in food production and reduce the detrimental impacts of extreme climatic events. Countries of the former Soviet Union are undergoing major economic changes, particularly in agricultural systems and management. This transition is likely to provide opportunities to change crop types and introduce more efficient irrigation-providing significant win-win options for conservation of resources to offset the projected impacts of climate change.

Human Health: Heat stress, affecting human comfort levels, and possible spread in vector-borne diseases are likely to result from changes in climate. Decreases in water availability and food production would lead to indirect impacts on human health.

Conclusions: Water is an important limiting factor for ecosystems, food and fiber production, human settlements, and human health in this arid region of the world. Climate change is anticipated to alter the hydrological cycle, and is unlikely to relieve the limitations placed by water scarcity upon the region. Climate change and human activities may further influence the levels of the Caspian and Aral Seas, which will affect associated ecosystems, agriculture, and human health in the surrounding areas. Win-win opportunities exist which offer the potential to reduce current pressures on resources and human welfare in the region and also offer the potential to reduce their vulnerability to adverse impacts from climate change.


Australasia includes Australia, New Zealand, and their outlying islands. The region spans the tropics to mid-latitudes and has varied climates and ecosystems, ranging from interior deserts to mountain rainforests. The climate is strongly affected by the oceanic environment and the ENSO phenomenon.

Ecosystems: Some of the region's ecosystems appear to be very vulnerable to climate change, at least in the long term, because alterations to soils, plants, and ecosystems are very likely, and there may be increases in fire occurrence and insect outbreaks. Many species will be able to adapt, but in some instances, a reduction of species diversity is highly likely. Any changes will occur in a landscape already fragmented by agricultural and urban development; such changes will add to existing problems such as land degradation, weeds, and pest infestations. Impacts on aquatic ecosystems from changes in river flow, flood frequency, and nutrient and sediment inputs are likely to be greatest in the drier parts of the region. Coastal ecosystems are vulnerable to the impacts of sea-level rise and possible changes in local meteorology. Tropical coral reefs, including the Great Barrier Reef, may be able to keep pace with sea-level rise-but will be vulnerable to bleaching and death of corals induced by episodes of higher sea temperatures and other stresses. Measures to facilitate adaptation include better rangeland management; plantings along waterways; and research, monitoring, and prediction. Active manipulation of species generally will not be feasible in the region's extensive natural and lightly managed ecosystems.

Hydrology and Water Resources: Vulnerability appears to be potentially high. Any reduction of water availability, especially in Australia's extensive drought-prone areas, would sharpen competition among uses, including agriculture and wetland ecosystem needs. Freshwater supplies on low-lying islands are also vulnerable. More frequent high-rainfall events may enhance groundwater recharge and dam-filling events, but they also may increase the impacts of flooding, landslides, and erosion, with flood-prone urban areas being heavily exposed to financial loss. Reduced snowpack and a shorter snow season appear likely, and New Zealand's glaciers are likely to shrink further. Some adaptation options are available, but the cost involved would be high.

Food and Fiber Production: Vulnerability appears to be low, at least in the next few decades (potentially high sensitivity coupled with high adaptability). Agriculture in the region is adaptable, and production increases are likely in some cases. However, there may be a trend toward increased vulnerability in the longer term-especially in warmer and more water-limited parts of Australia, where initial gains for some crops are eroded later as the delayed full effects of climate change (e.g., changes in temperature and precipitation) tend to outweigh the more immediate benefits of increased atmospheric CO2 concentrations. Impacts will vary widely from district to district and crop to crop. There will be changes in growth and quality of crops and pastures; shifts in the suitability of districts for particular crops; and possibly increased problems with weeds, pests, and diseases. Rangeland pastoralism and irrigated agriculture will be especially affected where rainfall changes occur. Changes in food production elsewhere in the world, which affect prices, would have major economic impacts on the region. With regard to forestry, the longer time to maturity results in a relatively large exposure to financial loss from extreme events, fire, or any locally rapid change in climate conditions.

Coastal Systems: Parts of the region's coasts and rapidly growing coastal settlements and infrastructure are very vulnerable to any increase in coastal flooding and erosion arising from sea-level rise and meteorological changes. Indigenous coastal and island communities in the Torres Strait and in New Zealand's Pacific island territories are especially vulnerable. Many adaptation options exist, although these measures are not easily implemented on low-lying islands. Moreover, climate change and sea-level rise generally are not well accommodated in current coastal management planning frameworks.

Human Settlements: In addition to hydrological and coastal risks, moderate vulnerability is present from a variety of impacts on air quality, drainage, waste disposal, mining, transport, insurance, and tourism. Overall, these effects are likely to be small relative to other economic influences, but they still may represent significant costs for large industries.

Human Health: Some degree of vulnerability is apparent. Indigenous communities and the economically disadvantaged may be more at risk. Increases are expected in heat-stress mortality, vector-borne diseases such as dengue, water and sewage-related diseases, and urban pollution-related respiratory problems. Though small compared with the total burden of ill health, these impacts have the potential to cause considerable community impact and cost.

Conclusions: Australia's relatively low latitude makes it particularly vulnerable to impacts on its scarce water resources and on crops growing near or above their optimum temperatures, whereas New Zealand's cooler, wetter, mid-latitude location may lead to some benefit through the ready availability of suitable crops and likely increases in agricultural production. In both countries, however, there is a wide range of situations where vulnerability is thought to be moderate to high-particularly in ecosystems, hydrology, coastal zones, human settlements, and human health.


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