Impact of Climate Change on Ground Water

Groundwater is an important resource for livelihoods and food security of billions of people, especially in developing countries of Asia. Although trends on abstraction and use in each country are not available, globally groundwater is estimated to provide approximately 50 per cent of current potable water supplies, 40 per cent of the water demand of self-supplied industry and 20 per cent of water use in irrigation. In Asia and the Pacific, about 32 per cent of the population uses groundwater as a drinking water source. Global climate change is expected to have negative effects on water resources as a result of increased variability in extreme events such as droughts and floods. Compared with surface water resources, there has been less research into the impacts of climate change on groundwater both in terms of the effects on quantity and quality and also linkages within the hydrological cycle. Climate change impacts may add to existing pressure on groundwater resources by (i) impeding recharge capacities in some areas; and (ii) being called on to fill eventual gaps in surface water availability due to increased variability of precipitation. Groundwater contamination is also expected in low elevation coastal zones due to sea level rise. In some vulnerable areas, such impacts on groundwater resources may render the only available freshwater reserve unavailable or unsuitable for use in the near future. This paper presents an over view of possible climate change impacts on groundwater using evidence from previous presented papers.