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Climate Change and Water Resources Management in Arid and Semi-arid Regions : Prospective and Challenges for the 21 st Century
| Content Provider | Semantic Scholar |
|---|---|
| Author | Ragab, R. Prudhomme, Christel |
| Copyright Year | 2002 |
| Abstract | The overgrowing population and the recent droughts are putting water resources under pressure and calling for new approaches for water planning and management if escalating con#icts are to be avoided and environmental degradation is to be reversed. As countries are using their water resources with growing intensity, poor rainfall increasingly leads to national water crises as water tables fall and reservoirs, wetlands and rivers empty. Global warming could cause further changes, further variability and further uncertainty. The UK Hadley Centre's global climate model was run at a spatial scale of 2)5 by 3)753 (latitude and longitude) grid squares to simulate the global climate according to scenarios of greenhouse gas concentration emission. Runs of the model assuming the emission scenario proposed by the Intergovernmental Panel on Climate Change in 1995 are analysed here for the 2050s time horizon. Outputs provide estimations of climate variables, such as precipitation and temperature, at a monthly time step. Those results, assumed representative of future climatic conditions, are compared to mean monthly values representative of the current climate and expressed in terms of percentage change. The results show that, for the dry season (April}September), by the 2050s, North Africa and some parts of Egypt, Saudi Arabia, Iran, Syria, Jordan and Israel, are expected to have reduced rainfall amounts of 20}25% less than the present mean values. This decrease in rainfall is accompanied by a temperature rise in those areas of between 2 and 2)753C. For the same period, the temperature in the coastal areas of the Mediterranean countries will rise by about 1)53C. In wintertime, the rainfall will decrease by about 10}15% but would increase over the Sahara by about 25%. Given the low rainfall rate over the Sahara, the increase by 25% will not bring any signi"cant amount of rain to the region. In wintertime, the temperature in the coastal areas will also increase but by only 1)53C on average, while inside the region it will increase by 1)75}2)53C. In southern Africa (Angola, Namibia, Mozambique, Zimbabwe, Zambia, Botswana and South Africa), results suggest an increase of the annual average temperature ranging between 1)5 and 2)53C in the south to between 2)5 and 33C in the north. The summer range is between 1)75 and 2)253C in the south, and increases towards the north to between 2)75 and 3)03C while the winter range is between 1)25 and 23C in the south, and increases towards the north to between 2)5 and 2)753C. On the other hand, the annual average will decrease by 10}15% in the south and by 5}10% in the north. The annual average decrease is 10%. However, some places will have an increase i.e. by 5}20% in South Africa in wintertime. In the Taklimakan region (Tarim Basin) west of China, the annual average temperature is shown to increase by 1)75}2)53C. Annual average rainfall should increase by 5}'25% in most of the region but decrease by 5}10% in some small parts. In summer, an increase by 5}15% is indicated in most of the region, and an increase by up to 25% or more during the wintertime. In the Thar Desert (India}Pakistan}Afghanistan), estimations suggest that the annual average increase in temperature ranges from 1)75 to 2)53C, ranging from 1)5 to 2)253C in winter and from 2 to 2)53C in summer. Annual average precipitation is shown to decrease by 5}25% in the region. The winter will have values closer to the annual average but the summer will have more decrease and most of the region will see a decrease closer to 25%. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.southwestnrm.org.au/sites/default/files/uploads/ihub/ragab-r-prudhomme-c-2002-climate-change-and-water-resources-management.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
