Climate change impacts on water for irrigating paddy rice in South Korea

Abstract

AbstractThe spatial and temporal impacts of climate change on paddy irrigation water demands in South Korea have been modelled and mapped. The outputs from a general circulation model (HadCM3) for two selected scenarios (A2, B2) of the Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios (IPCC SRES) and for two time periods (2050s and 2080s) have been downscaled and applied to a baseline climatology (1961–1990) developed by the International Water Management Institute. A GIS was used to map spatial changes in irrigation water requirements.The simulations showed that although future average rainfall is expected to increase substantially (25–53%), average effective rainfall will only increase slightly (2–8%), leading to only slight reductions in paddy irrigation requirements (−1 to −8%). Assuming cropping patterns and farming practices remain unchanged, total volumetric irrigation water demand decreases by 4–10%. However, the spatial variations are substantial.Combining these results with previously forecast increases in the available water resources under the SRES A2 scenario, the ratio between available water resources and volumetric irrigation demand would increase significantly. However, most of the increased rainfall falls after the peak demand period. Potential adaptation strategies such as constructing more storage reservoirs can be considered where water shortages still occur. Copyright © 2010 John Wiley & Sons, Ltd.