Scientists predict extreme global water shortages by 2100

The earth’s climate and its water are inextricably linked – one cannot exist without the other. As the climate undergoes an unprecedented change and human focused, the global water system also changes.

Although this link is well established, it is difficult to predict exactly when and where the extreme water shortages will occur as a result of climate change. This uncertainty inhibits the ability of decision -makers to prepare for these catastrophic scenarios. A new study published Tuesday in the journal Nature Communications aims to fill this lack of knowledge by estimating the calendar and the probability of events of extreme water – also known as “zero drought” events in the world.

“The day zero would be essentially the moment when the region or the city is lacking in water,” a professor in the co-author Christian Franzke, professor at IBS Center for Climate Physics in Busan, South Korea, in Gizmodo.

Extreme droughts can come earlier than we thought

Drought events of the zero day result from stressors of stress composed on a local or regional water system, such as prolonged precipitation shortages, reduction in the flow of the river and an increase in water demand. Franzke and his co-author Vecchia P. Ravinanda, a doctoral student at the IBS Center, projected the results of the global water shortage by applying a probabilistic framework to a large set of climate model simulations that take into account all these stress factors.

Their results suggest that at the end of the century, 74% of the regions subject to drought in the world – including those with major tanks – will risk a high risk of serious and persistent droughts in a high emission scenario. Almost 35% of these regions can experience a serious water shortage by 2030.

This means that 753 million people, 467 million of whom live in urban areas, could be vulnerable to an extreme water shortage of less than 2.7 degrees fahrenheit (1.5 degrees Celsius) of warming above pre-industrial levels. In addition, the time between individual drought events of the day zero can be shorter than the events themselves, limiting the recovery time and exacerbating the risks of water shortage.

The results indicate that water stress could become particularly severe in the western United States, the Mediterranean, North Africa, Southern Africa, India, northern China and South Australia, because demand quickly exceeds supply.

Franzke stresses that these are projections, not predictions. Modeling can only tell us as much about future climate change and their consequences. However, “we were surprised by the speed with which it can start to happen,” he said.

How decision -makers can use this data

The study provides a complete and rapid estimate of the future risk of water shortage, Auroo Ganguly, a distinguished professor of civil and environmental engineering at the Northeastern University who was not involved in research, told Gizmodo.

“The challenge of water (rarity) is felt worldwide, but what must be done is often local, or at least regional,” he said. The time of the zero -day drought events and the recovery time available to each other vary considerably depending on the region. By capturing these differences, researchers provide theoretical deadlines that can help guide both short -term emergency responses and long -term policies planning.

However, there is more work to do. In future analyzes, Franzke would like to incorporate data from more climate models to further reduce uncertainty, he said, stressing the fact that his data set did not directly play the role of groundwater as a buffer against drought.

Ganguly also underlined the need for a more robust data set. As such, he warned against the fact of seeing this document as “the last word” on the risk of water shortage in a changing climate, but rather as a guidance element to understand the urgency of preparing for this risk.