Climate Change may pose serious threat to freshwater availability in North India by 2060

• Climate change has contributed to serious depletion of terrestrial water storage over the Tibetan Plateau

• Nearly 2 billion people living downstream depend on ‘The Tibetan Plateau’ for freshwater

• North India and its adjoining areas in Asia may face a major ‘irreversible fresh water scarcity by 2060’ because of climate change. 

• Stringent climate policies are needed to ensure that there is a substantial reduction in carbon emissions over the next decades

• Adoption of alternative water supply sources like intensified groundwater extraction and water transfer projects is necessary

Climate Change is posing a serious threat to freshwater availability in North India which is the most populated region of the country. According to a recent study, regarded as the most comprehensive study to date on water storage in Tibetan Plateau, North India and its adjoining areas in Asia will face a major ‘irreversible fresh water scarcity by 2060’ because of climate change under a scenario of weak climate policy. 

The study published in the journal ‘Nature Climate Change’ titled ‘Climate change threatens terrestrial water storage over the Tibetan Plateau’ projects that climate change aided by weak climate-related policies will lead to irreversible scarcity of freshwater storage in the region. The research led by scientists at Penn State, Tsinghua University and the University of Texas at Austin found that there is a serious threat to the water supply for central Asia, Afghanistan, Northern India, Kashmir and Pakistan by 2060.

According to the study, central Asia and Afghanistan might witness a total collapse of the water supply system whereas Northern India and Pakistan might witness a near-total collapse of the water supply system by the middle of the century.

One of the co-authors of the study, Michael Mann, distinguished professor of atmospheric science at Penn State in US said, “The prognosis is not good. In a ‘business as usual’ scenario, where we fail to meaningfully curtail fossil fuel burning in the decades ahead, we can expect a near collapse – that is, nearly 100 per cent loss – of water availability to downstream regions of the Tibetan Plateau.” 

The Tibetan Plateau

Nearly 2 billion people living downstream depend on ‘The Tibetan Plateau’, popularly known as the ‘water tower’ of Asia, for freshwater. It is sometimes referred to as the ‘Third Pole’ because, after the two poles, it is the single largest global store of fresh water in the frozen form. It contains the headwaters of the drainage basins of most of the streams and rivers in surrounding regions. Reports have emerged now that the region is witnessing rapid melting because of global warming and climate change. As these frozen reserves of fresh water are making their way down to the oceans, they are also contributing to sea-level rise. 

Researchers connected with the above-mentioned study said that the impacts of climate change on the terrestrial water storage (TWS) in the Tibetan Plateau have not been properly explored even though the region has long been considered a climate change hotspot.

According to ScienceDirect, “Terrestrial water storage can be defined as the summation of all water on the land surface and in the subsurface. It includes surface soil moisture, root zone soil moisture, groundwater, snow, ice, water stored in the vegetation, river and lake water.”

“The Tibetan Plateau supplies a substantial portion of the water demand for almost 2 billion people,” said Di Long, associate professor of hydrologic engineering, Tsinghua University, China “Terrestrial water storage across this region is crucial in determining water availability, and it is highly sensitive to climate change.”

The Process

The team of researchers used satellite-based and ground-based measurements of water mass in glaciers, lakes and below-ground sources, combined with machine learning techniques to determine the net change in water and ice mass over the past two decades and also make projections over the next four decades under scenarios such as higher air temperature and reduced cloud cover.

What is significant is also the fact that the researchers were successful in establishing consistency between satellite-based and ground-based approaches in comparison to previous studies which points to the fact that the findings in this study are more accurate. 

Findings

The study found that climate change has contributed to a significant depletion of water level [depletion in TWS (15.8 gigatons/year) in certain areas of the Tibetan Plateau and increase in TWS (5.6 gigatons/year) in others] which is 10.2 gigatons/year over the Tibetan Plateau during the 2002-2017 period. This is happening in likelihood due to the ‘competing effects of glacier retreat, degradation of seasonally frozen ground, and lake expansion’.

The study further projects that, given that the carbon emissions remain at moderate levels, the Tibetan Plateau in its entirety could witness a net loss of about 230 gigatons of water by the middle of the 21st century in comparison to an early 21st-century baseline. The projections suggest that the Indus basin which supplies water to North India will witness a decline of 79% in water supply capacity. 

“Our study provides insights into hydrologic processes affecting high-mountain freshwater supplies that serve large downstream Asian populations,” said Long. “By examining the interactions between climate change and the TWS in the historical period and future by 2060, this study serves as a basis to guide future research and the management by governments and institutions of improved adaptation strategies.”

Mitigation

Apart from ensuring that we have stringent climate policies ensuring that there is a substantial reduction in carbon emissions over the next decades, experts noted that the adoption of alternative water supply sources like intensified groundwater extraction and water transfer projects is necessary to meet the severe water crisis in the future. 

Mann added, “Substantial reductions in carbon emissions over the next decade…can limit the additional warming and associated climate changes behind the predicted collapse of the Tibetan Plateau water towers. But even in a best-case scenario, further losses are likely unavoidable, which will require substantial adaptation to decreasing water resources in this vulnerable, highly populated region of the world.”