NEW DELHI: An irreversible decline in freshwater storage projected in parts of Asia due to climate change could impact 2 billion people living downstream of the Tibetan Plateau as it could pose a serious threat to water supplies to India, Afghanistan, and Pakistan by mid-century, according to the satellite-based assessment of water changes in Tibetan Plateau.
TWS over the Tibetan Plateau, a major global water tower, is crucial in determining water transport and availability to a large downstream Asian population. The assessment over the last two decades (2002-2020) and projection for 2021-2060 are based on measurements of water mass in glaciers, lakes, and below-ground sources, combined with machine-learning techniques to provide a benchmark of observed TWS changes, reflecting competing effects of glacier retreat, lake expansion, and subsurface water loss.
Research led by scientists at Penn State, Tsinghua University, and the University of Texas at Austin project that climate change, under a scenario of weak climate policy, will cause irreversible declines in freshwater storage in the region, constituting a serious threat to the water supply for central Asia, Afghanistan, Northern India, Kashmir, and Pakistan.
“In a business as usual scenario, where we fail to meaningfully curtail fossil fuel burning in the decades ahead, we can expect a substantial that is, nearly 100% loss of water availability to downstream regions of the Tibetan Plateau. I was surprised at just how large the predicted decrease is even under a scenario of modest climate policy,” said Michael Mann, professor of atmospheric science at Penn State. The research is published in the journal Nature Climate Change.
According to the researchers, despite its importance, the impacts of climate change on past and future TWS which includes all the above — and below—ground water — in the Tibetan Plateau have largely been underexplored. Climate change in recent decades has led to a 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 team’s projections for future TWS under a moderate carbon emissions scenario - specifically, the mid-range emissions scenario — suggest that the entire Tibetan Plateau could experience a net loss of about 230 gigatons by the mid-21st century (2031 to 2060) relative to an early 21st century (2002 to 2030) baseline.
Water supply faces serious threat
Shortage in freshwater storage over Tibetan Plateau can impact 2 billion people
The study of water availability included
Future prediction
Net loss of 230 gigatons by mid-21st century
Excess water loss in
Amu Darya basin by 119% (supplies water central Asia and Afghanistan)
Indus basin by 79% (supplies water to Northern India & Kashmir)
Pose threat to water supplies in
- Climate change led to depletion in Terrestrial Water storage (TWS) (-15.8 gigatons/year) in some areas
- Whereas led to substantial increase (5.6 gigatons/year) in others