Need for integrated water and climate agenda

There is a need for India to undertake planned efforts to address climate change mitigation and adaptation. Improving water-use efficiency, strengthening early water-warning systems with precision for flood forecast, adopting climate-proofing of cities and resilience measures, increasing groundwater storage, well-managed effluents and other wastewater should be initiated as major steps. Groundwater has to be used in a sustainable way.

threat: Human-induced climate change is now a stark reality. PTI

SK Sarkar

Distinguished Fellow, The Energy and Resources Institute, New Delhi

THE UN World Water Day in 2020 dealt with the critical theme of ‘Water and Climate Change’, aimed at drawing attention to the complex relationship between water and climate change and understanding their impact on society. However, no such climate discussions have taken place in the water sector since 2020, although various UN climate negotiations were held. It was so until the recently concluded UN climate negotiations — COP27 held in Egypt — where global pathways to achieve an integrated water and climate agenda were suggested.

Human-induced climate change is now a stark reality. The Intergovernmental Panel on Climate Change (IPCC) report (2015) predicts that global warming is likely to reach a range of 1.4 to 2.6°C between 2046 and 2065, if it continues to increase at the current rate.

A warmer atmosphere can hold more water. Occurrence of extreme events which will affect rainfall, snowmelt, river flows and groundwater has been predicted by the IPCC. The hydrological cycle is predicted to be more intense with higher annual rainfall and increased drought, which are expected to increase the surface water variability. This may result in the world witnessing more floods, more erosions, sedimentation and sand deposition due to the change in course of rivers.

When ocean gains heat due to climate change, water expands, and sea level rises. Rising sea levels have an adverse effect on the quality of water. It contaminates fresh water, especially groundwater, which becomes saltier. Creating fresh water from saltwater is costly and unsustainable.

There are multiple benefits to be derived from improved management of water resources in the context of climate change, such as reducing water-related disasters, strengthening climate adaptation and resilience, and helping greenhouse gas emission reduction.

The water industry is also a source of carbon emission from energy consumption as well as of nitrogen oxide and methane emissions from process emissions in wastewater systems, which contribute to about 3.5 per cent of the global CO2 from energy consumption and methane and NO2 from wastewater handling. Water is an essential factor in emission reduction and capturing carbon and it is a necessary feedstock for hydrogen production, and growing plants for biofuels. Well-managed effluents and other wastewater enable the reuse and reduction of methane and NO2. Water service providers should also improve their water and energy efficiency and adopt low emission pumping and water harvesting infrastructure to improve the climate agenda.

Improved water management helps in contributing to human rights and livelihood, public health, maintenance of biodiversity, poverty reduction, job creation, and economic development. Even in the case of trans-boundary water basins, cooperative water management contributes to cross-border cooperation.

To address the variability of water resources due to climate change, one option is to have additional storage of water resources. Although water storage capacity in India has substantially improved as compared to pre-independence days, it remains low when compared to international standards. For example, the per capita water storage capacity in India is about 209 cubic metres (m3), whereas in the USA it is 2,193 m3; Brazil, 2,632; and China, 416.

Construction of new storage systems for surface water is not always easy as this is restricted due to shortage of land and high population density. There is also public resistance to constructing large dams, a reason why the construction of such dams in India is delayed. Also, water storage cannot be built at will as this is dictated by topography.

These constraints call for looking at the option of enhancing groundwater storage in India. Our country is highly dependent on groundwater resources and is its highest user in the world; contribution of groundwater is nearly 62 per cent in irrigation, 85 per cent in rural water supply, and 45 per cent in the urban water supply. During 2008-17, data reveals that about 52 per cent wells show a decline in water levels. The depleting groundwater level and its contamination are causes for concern.

Aquifers are the resources which are an underground layer of porous and permeable rock capable of storing groundwater and transmitting to the wells. To enhance recharge of aquifers, programmes such as rainwater harvesting, watershed development and artificial recharge facilities with wastewater are often undertaken. Artificial recharge of groundwater has a proven advantage, and identification of aquifers is necessary. Artificial recharge is a major intervention to increase groundwater resources as it enhances infiltration. The source water can be rainwater or from other sources such as canals or treated wastewater. This type of recharge is an addition to the natural recharge as it results in increased availability of groundwater in the spatio-temporal domain. It is a fact that natural recharge is a very slow process. However, regions like Indo-Gangetic-Brahmaputra Plains have higher recharge rate due to high rainfall, storage capacity of aquifer and better permeability.

The Central Government has initiated Atal Bhujal Yojana, under which mapping and management of groundwater are being done in select states/districts of the country. The purpose is to manage groundwater in a sustainable manner. Involving communities in groundwater management is essential and there is a need for detailed hydrological studies on aquifers before implementing additional storage of groundwater on a large scale for mitigating increased runoff from rivers due to climate change.

There is a need for India to undertake planned efforts to address climate change mitigation and adaptation issues. Improving water-use efficiency, strengthening early water-warning systems with precision for flood forecast, adopting climate-proofing of cities and resilience measures, increasing groundwater storage, well-managed effluents and other waste water should be undertaken as major steps. An action plan for an integrated water and climate agenda is called for at this critical time.