Variantes  estructurales

Finally, despite the assumptions and uncertainties associated with the climate models and crop water simulation, this paper presents where and how agricultural water use (both irrigation requirements for irrigated crops and water deficits for rainfed crops) will likely be affected by climate change from a biophysical perspective. The predicted impacts display high heterogeneity spatially and vary with crop. The broad-scale analysis presented here aims to identify the regions where concerns may arise with relatively high likelihood: further studies at finer scales are needed for water resources planning and management. In particular, the predicted changes of WD for some countries or regions are sensitive to the emission and model scenarios. This uncertainty needs to be addressed through downscaling processes and/or the improvement of GCMs. It should also be noted that extreme weather events associated with climate change, such as heat waves and droughts, will affect irrigation at the local scale and the extent to which these events will affect the regional, long-term estimation of water use needs additional investigation. Other factors, such as seasonal variability and monsoonal climates, may also affect the accuracy of the estimates and can be addressed with more refined data and more sophisticated climatic and agronomic models.

Furthermore, studies investigating related issues, including agricultural water use efficiency and drought tolerant crops, would help provide a more comprehensive assessment of future agricultural

43

water situation. The actual water requirement will finally be influenced by adaptation measures at the local level, most likely in a positive direction.

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