A solution to limit Asia's growing water shortage

Experts have found a way to reduce the risk of severe water-access problems in Asia, a new study has claimed.

According to the Massachusetts Institute of Technology-study, even 'modest' action to limit climate change could help prevent the most extreme water-shortage scenarios facing Asia by the year 2050.

The study took an inventive approach to model the effects of both climate change and economic growth on the world's most heavily populated continent.

Roughly 60 percent of the global population lives in Asia, often with limited access to water: There is less than half the amount of freshwater available per inhabitant in Asia, compared to the global average.

To examine the risk of water shortages on the continent, the researchers conducted detailed simulations of many plausible economic and climate pathways for Asia in the future, evaluating the relative effects of both pathways on water supply and demand.

The MIT-based team found that with no constraints on economic growth and climate change, an additional 200 million people across Asia would be vulnerable to severe water shortages by 2050.

However, fighting climate change along the lines of the 2015 Paris Agreement would reduce by around 60 million the number of people facing severe water problems.

But even with worldwide efforts to limit climate change, there is a 50 percent chance that around 100 million people in southern and eastern Asia will experience a 50 percent increase in 'water stress' - their inability to access safe water - and a 10 percent chance that water shortages will double for those people.

"We do find that a mitigation strategy can reduce the heightened risk of water stress in Asia," said Adam Schlosser, the co-author of the study. "But it doesn't solve it all."

The authors are Xiang Gao, Charles Fant, and Kenneth Strzepek.

The research team also used models that track municipal and industrial activities and their specific water-demand consequences across many smaller sub-regions in Asia. Irrigation tends to be a major driver of water consumption, leading to diminished access to water for other uses.

Overall, the researchers concluded, through the mid-21st century, "socioeconomic growth contributes to an increase in water stress" across the whole region, but climate change can have "both positive and negative effects on water stress."

The study turned up a notable amount of regional variation in the effects of climate change within Asia. Climate change by itself is likely to have a more adverse impact on water access in China than in India, for instance, where a warming climate could produce more rain.

Apart from the most likely scenarios, another significant finding is that the potential for extreme water stress is associated with unabated climate change.

As the authors stated in the paper, "A modest greenhouse gas mitigation pathway eliminates the likelihood of ... extreme outcomes in water access."

But without any such climate measures, "both countries have a chance of experiencing extreme water shortages by midcentury," Gao said.

The study appears in the journal Environmental Research Letters.