Assessing the Impact of Population Growth, Climate Change, and Land Use Change on Water Resources in India

Abstract:

India is poised to become the most populous country in the world by 2019 and reach a population of over 2 billion by 2050 based on current growth rates. It is also a region which will be under severe socio-economic and environmental stress if mitigation efforts are not adapted. In the past 10 years the population of India has grown by an average rate of 17 million people per year. In addition to unprecedented population growth, rapid urbanization and industrialization are straining the overburdened environmental system. This rapid growth in population, urbanization and industrialized will result in increased demand for food, requiring expansion of agricultural resources. Since total agricultural land in India has been relatively constant over the past 10 years the demand for additional food has to be partly met by enhanced production on existing land. Arable land in India has declined by around 3% according to FAOSTAT while the total agricultural area under irrigation has increased by about 9% thus further straining its water resources. In addition projections for future climate indicate that India is one of the regions where water resources are expected to be negatively impacted. Total agriculture water withdrawal in India increased by approximately 18 % from 2000-2010 while the total per capita water withdrawal increased by over 9% from 2000-2010. Total freshwater withdrawal as percentage of renewable water resources was around 40% in 2010. In addition, recent mandates of biofuel policies in India are also expected to impact its water resources. The combined impact of these various factors on future water availability in India could be one of the most severe globally due its unprecedented increase in population, food production and industrialization. In this study we assess the impact of land use and climate change on water resources over southern India in the face of a growing population and interest in development of national biofuel supplies. We use observational data on historical climate and land use, and future climate projections to drive a coupled hydrological-crop simulation model to quantify these changes and asses their impacts.