The impact of climate change on water resources

Abstract

Water resources are a crucial resource for the well being of mankind. Water supports human life not only from a personal hygiene or drinking point of view but also from the food it enables to support for human consumption. It is in this context that the availability of freshwater resources is always under review. The impact of climate change on water resources has raised concerns on the dynamics of freshwater resources in response to projected changes in climatic parameters. Many studies have been conducted both at an international, regional and local scenario. The IPCC Fourth Assessment Report 2007 (FAR) clearly states that warming of the climate system is unequivocal as evidenced from observations of increases in global average air and ocean temperatures and average sea level amongst other parameters. The report states that eleven of the last twelve years (1995-2006) rank among the twelve warmest years in the instrumental record of global surface temperature (since 1850) with a 100- year linear trend (1906-2005) of 0.74 [0.56 to 0.92] °C which is larger than the corresponding trend of 0.6 [0.4 to 0.8]°C (1901-2000) given in the Third Assessment Report (TAR). Global average sea level has risen since 1961 at an average rate of 1.8 [1.3 to 2.3] mm/yr and since 1993 at 3.1 [2.4 to 3.8] mm/yr, with contributions from thermal expansion, melting glaciers and ice caps, and the polar ice sheets. Whether the faster rate for 1993 to 2003 reflects decadal variation or an increase in the longer-term trend is unclear (Gatt, 2009). [Excerpt]