To combat the impact of global warming, it is vital to improve innovation in providing support for new technologies in the water sector, in devising innovative instruments for enhancing groundwater storage and ensuring active participation of various stakeholders, including the private sector
The disastrous effects of human-induced climate change are now a reality. Across the world, there is an effort to maintain global warming below 2°C over the century relative to pre-industrial level. The impacts of climate change on water are predicted to be many: Extended summer season causing less rainy days, late onset of the monsoon season, intense precipitation, the recurring occurrence of drought and flash floods, glacier melts and heavy snowfall during winters. Each of these phenomena influences the water resources on Earth.
Glaciers form an integral part of India’s water resource system. Over 9,000 glaciers are the sources of major Indian rivers like the Indus, the Ganga and the Brahmaputra and thousands of their tributaries. Meltwater from glaciers sustains river flows during the summer and ensures year-round water availability in these river basins. With increasing temperature, enhanced melting of glaciers has been recorded and over the last four decades they have been reduced by 0.2–0.7 per cent annually.
According to the Indian Meteorological Department (IMD), the normal rainfall pattern in the country has changed from 1951-2010. There is an increase in total rainfall in western and eastern India while it has decreased in States in central and northern India. Major States showing a decrease in annual rainfall are Uttar Pradesh (UP), Maharashtra, Madhya Pradesh and Karnataka, while West Bengal, Gujarat and Bihar are showing an increasing trend in annual rainfall. UP, the most populous State of India, is now receiving reduced rainfall in all seasons while Bihar and West Bengal, two of the most densely-populated States of the country are receiving increased rainfall in almost all the seasons.
Although India has 1.91 km3/year of total freshwater resources, it ranks 132 in per capita water availability in the world. The per capita annual availability at 1,545 cubic metres is touching the water-stressed benchmark in India.
The spatial and temporal distribution of water resources is highly uneven with per capita water resource availability varying from basin to basin. In the Brahmaputra river basin, it is 17,000 m3, while it is 240 m3 in the Sabarmati basin in western India.
The impact of climate change on India’s water resources presents a major challenge for the success of Government schemes like Jal Jeevan Mission and achievement of the United Nation’s (UN’s) Sustainable Development Goals of ensuring universal access to safe drinking water. Changes in precipitation will have a significant influence on the design of hydrological structures, flood and drought management and urban planning and development. India’s agrarian economy, which relies heavily on the monsoon and available water for production, is particularly vulnerable to the projected climate changes.
For mitigating the impact of climate change on water vulnerability, the storage of water in many forms is highly desirable. India’s per capita water storage capacity is one of the lowest in the world. It is also not always a sustainable option. In that case, enhancing the groundwater storage should be a viable option.
Interestingly, technologies play a significant role in minimising water variability to climate change impacts. The UN recognises that technologies for adaptation could be either in the “hard” form, involving materials or equipment, or in the “soft” form, like diverse forms of knowledge, new insurance schemes or crop rotation patterns.
Also, for efficient adaptation to climate change, a combination of technologies is required — “traditional”, like conventional methods of water conservation; “modern”, like drip and sprinkler irrigation systems; as well as “high” technologies like remote sensing and Geographical Information System.
The “three Rs” — reduce, reuse and recycle — concept still holds tremendous opportunities not just for ensuring water security but also for the adaptation to climate change impacts. The entire spectrum of adaptation technologies in the water sector in India needs to focus on these “three Rs”. To reduce the wastage of water, the efficiency of water usage needs to be improved —especially in the agriculture sector (water use efficiency in this sector is about 38 per cent), which is the biggest consumer of water. Changes in cropping patterns, crop rotation as well as efficient drip and sprinkler technologies, need to be adopted on a much wider scale than the present. Rather than trying to transfer water from distant sources, the focus should be to exploit local resources by harvesting rain or stormwater and treat wastewater locally, using “green infrastructure” such as sand filters and wetlands.
Similarly, technologies like “Air to Water”, condensing atmospheric moisture to provide drinking quality water, need to be provided the strong impetus, which has the potential to provide sustainable water sources at the local level. This technology also saves groundwater resources. Also, for the success of programmes like Jal Jeevan Mission, the focus should be on conservation and utilisation of “green water”, which is the precipitation that is absorbed by soil and plants and subsequently returned to the atmosphere through plant transpiration.
For climate change adaptations, it is essential to improve innovation in providing support for new technologies in the water sector, in devising new instruments for enhancing groundwater storage, financing water sector projects and ensuring active participation of various stakeholders including the private sector.
(Sarkar is distinguished fellow, Water Resources and Tayal is senior fellow, Water Resources Division, TERI)