Chapter 3 - Impact of climate change on water quality and its assessment

Abstract

Worldwide changes in climatic conditions are encouraged by increase in the concentration of Green House Gases (GHGs), are widely perceptible in terms of continuous changing patterns of superficial temperature, rainfall pattern, wind-flow patterns, radiations, and other life-threatening weather conditions. With a wider consent from the regional and global scientific communities, Intergovernmental Panel on Climate Change (IPCC) has indisputably summarized that kind of fact. Therefore, in this ongoing era of global climate-change, the assessment of probable impact on water and its quality, being the most prominent and reliable resource for human existence, become a significant task. Lots of assessment and review study have been reported on the possible impact of climate-change on water cycling and precipitation pattern. Recently, in-situ quality assessment, satellite observational assessment, and modeling simulation studies are in progress to assess the possible impact of climate change on the quality of available water. These studies mostly reported that the rising temperature and hence changing climatic conditions are capable of varying the ecological balance of water as well its qualitative contents either by its indirect impact or by direct impact by performing various biochemical alternations, as the rise in the water temperature and changes in extremes like flash-flood worsen various reasons of pollution caused in water bodies. In a natural water system, sediment load, nutrients availability, dissolved organic carbon, and essential zoo planktonic community are found to be in a delicate balance. Change in the flow pattern and thus augmentation in nutrients concentration, predictable variation in climatic phenomenon leads to periodic phytoplankton blossoms and alteration of the ecological tropical balance. The resultant dissolved oxygen (DO) level is varied constantly and algal-blooms may range to the perilous level to affect negatively. In addition, melting glaciers and consequent rising levels of the sea are expected to encompass the zones of salinization toward freshwater resources, which results in the reduction in available freshwater resources in the coastal areas. Additionally, variations in the qualitative value of water are predictable to affect nutriment accessibility, steadiness, access, and consumption. All these detrimental effects of changing climate hence water quality can adversely impact food security and hence enhancing the vulnerability of the agriculturalists and civilizations of our rural culture surviving in arid regions like Asian and African deltas (IPCC, Technical report on climate change and water, June 2008).