North India, the most populated belt of the nation is going to face grievous irreversible fresh water scarcity by 2060 since the availability of the vital resource will decline on account of climate change.
Roof of the world, Tibetan Plateau, also known as the “water tower” of Asia, supplies freshwater for nearly 2 billion people who live downstream. As noted by a team of international researchers.
A study, published in the journal ‘Nature Climate Change’ titled ‘Climate change threatens terrestrial water storage over the Tibetan Plateau’ on Monday, projects that climate change clubbed with weak climate policy, will cause irreversible declines in freshwater storage in the region.
The study predicts a total collapse of the water supply for central Asia and Afghanistan and a near-total collapse for Northern India and Pakistan by the middle of the century.
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.”
Researchers stated, the impacts of climate change on past and future terrestrial water storage (TWS) in the Tibetan Plateau have largely been under explored even though they are extremely significant.
“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.
Long added, “Terrestrial water storage across this region is crucial in determining water availability, and it is highly sensitive to climate change.”
Professor Mann said, the absence of reliable future projections of TWS limits any guidance on policy-making, despite the fact that the Tibetan Plateau has long been considered a climate change hotspot.
Technique used to predict
The researchers used 2 methods to measure the water reserves, “top-down” – or satellite-based – and “bottom-up” or ground-based to measure the water mass in glaciers, lakes and below-ground sources.
They combined the data with machine learning techniques to provide a benchmark of observed TWS changes over the past two decades (2002‒2020) and projections over the next four decades (2021–2060).
The researchers combined plethora of factors together and used a novel neural net-based machine learning technique to relate these observed changes in total water storage to key climate variables, including air temperature, precipitation, humidity, cloud cover and incoming sunlight.
The findings
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The researchers found that climate change in recent decades has led to severe depletion in TWS (15.8 gigatons/year) in certain areas of the Tibetan Plateau and substantial increases in TWS (5.6 gigatons/year) in others, likely due to the competing effects of glacier retreat, degradation of seasonally frozen ground, and lake expansion.
The entire Tibetan Plateau could experience a net loss of about 230 gigatons by the mid-21st century (2031‒2060) relative to an early 21st century (2002‒2030) baseline, as suggested in the team’s projection given that the carbon emissions remain at moderate levels.
Excess water loss projections suggest that the Amu Darya basin – which supplies water to central Asia and Afghanistan – and the Indus basin, which supplies water to Northern India, and Pakistan, will witness decline of 119 per cent and 79 per cent in water-supply capacity, respectively.
With inputs from PTI.
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