Impact of Climate change on Water Resources
Introduction:
No one can deny the effect of climate change as a phenomenon, which is increasingly becoming evident to affect the food, water and energy security worldwide. With increase in temperature, there has been a significant impact on the fresh water supplies. Rise in temperature results in increase in evaporation, which could result in droughts. This could also result in melting of glaciers, thus resulting in disappearance of one of the important sources of fresh water. Snow and ice in the high altitudes and Polar Regions store water in the form of glaciers that gets released slowly when they melt during the warmer seasons.More than 50% of the world’s freshwater comes from the mountain runoff and snow melts. But increased melting of glaciers and reduction of precipitation in the form of snow, results in water shortages as water runoff happens more quickly.
Heavy precipitation events will become more frequent over most regions in the 21st century, resulting in increased risk of flash flooding and urban flooding (IPCC, 2007). This increased run off also means that there will be reduced groundwater recharges and decreased levels of soil moisture, which can result in reduced agricultural productivity as well.
There are more concerns that climate change raises with respect to it’s impact on water resources. Large amounts of energy are required to find water supplies and to treat them, which also contributes to the climate change. The filtering units, bottled water also contribute to greenhouse gas emissions with the increased energy requirements to produce them as well as to transport.
IPCC (2007) during their studies had observed the following changes specific to water resources due to climate change in last two centuries all around the world(IPCC, 2007):
Situation in India:
Climate change is expected to result in intensification on global hydrological cycle and with respect to India, this will have a severe impact on per capita availability of water as well. Just by taking into consideration the population as per the 2001 census, the per capita availability is calculated as:
Thus at a macro level, clearly India is in a water stressed state. In local/regional level it could be even starker, considering the high variations in water availability across the country. When we apply the impact of climate change, the per capita availability is bound to decrease further more in future.
Also out of the 22 river basins mentioned by CWC(Central Water Commission), eight river basins (Cauvery, Pennar, Mahi, Sabarmati, Tapi, East flowing rivers between Mahanadi and Pennar, and East Flowing rivers from Pennar to Kanniyakumari, West flowing rivers from Kutch and Saurashtra are already regarded to be water scarce with water availability of less than 1000 m3/year. It is also projected that Ganga, Subranarekha and Krishna will also get added to the list by 2025.
The way forward:
Rational adaptation strategies need to be developed to minimize the adverse impacts of climate change on water resources and for sustainable management. With respect to India, the National Action Plan on Climate Change was formed with eight missions. National Water Mission is one of those missions and has the objective to ensure integrated water resource management and conserve water resources, reduce the wastage, increase efficiency and ensure equitable distribution across and within states.
But in spite of these policies, there is a need for institutional arrangements, political will and action from both state and citizen actors so that the implementation of these policies results in a sustainable and positive impact on the water resource management. Climate change thus provides an opportunity to revisit our water resources in terms of understanding, planning and management (SANDRP, 2012).
Promotion of Adaptation Strategies:
While planning, designing and operation of water resources projects, proper assessment of water resources as well as effects due to climate change should be done.Moreover local strategies for water resource planning should be devised based on the natural boundary of surface water asthe hydrological boundary – the river basin. There is a need to focus on the protection of the vulnerable sections of the society who are severely impacted due to climate change and to make them resilient through awareness on the climate change impacts and strategies in general and with respect to water resources in particular.
Decentralized Decision making and Planning:
There is a need to come up with decentralized approach taking into consideration the local impacts and also strengthening of the local level state institutions and citizen groups in devising the adaptation and mitigation strategies and implementing them. There is a need to marry traditional and modern knowledge while planning strategies, to bridge the knowledge gaps and making decision-making process participatory and through knowledge exchanges.
Multi-sectoral, trans-disciplinary approaches:
Multi-sectoral, trans-disciplinary approaches should be devised with protection strategy for the rivers, forests, wetlands, ground water resources and ecology. When it comes to planning of water resources, rather than looking in from a silo approach which looks into sectors as domestic, industries, agriculture, environment or as drinking water, waste water, industrial water or as surface water and ground water etc. there is a need to develop strategies which looks into the inter linkages between the various sectors, sources and usages.