Simultaneous droughts could threaten global food security

Droughts occurring at the same time in different regions of the planet could put unprecedented pressure on the global agricultural system and threaten the water security of millions of people , according to a new study published in Nature Climate Change.

A research team led by Washington State University analyzed data on climate, agriculture, and population growth to show that continued reliance on fossil fuels will increase the probability of simultaneous droughts by 40% by the middle of the 60st century and XNUMX% by the end of the XNUMXst century, relative to the end of the XNUMXth century. That translates to a roughly nine-fold increase in the exposure of the agricultural and human population to simultaneous severe droughts, unless steps are taken to reduce carbon emissions.

"There could be around 120 million people around the world simultaneously exposed to severe compound droughts each year by the end of the century," said lead author Jitendra Singh, a former postdoctoral researcher at the WSU School of the Environment now at ETH Zurich. Swiss. . “Many of the regions that our analysis shows will be hardest hit are already vulnerable, so the potential for droughts to turn into disasters is high.”

The elevated risk of compound droughts estimated by Singh and colleagues is the result of a warmer climate coupled with with a projected 22% increase in the frequency of El Niño and La Niña events , the two opposite phases of the El Niño Southern Oscillation (ENSO).

The researchers' projections show that nearly 75% of future composite droughts will coincide with these irregular but recurring periods of climatic variation in the world's oceans, which have played a major role in some of the biggest environmental disasters in world history.

For example, El Niño-induced droughts that occurred simultaneously in Asia, Brazil, and Africa during 1876-1878 led to synchronous crop failures, followed by famines that killed more than 50 million people.

"While current technology and other circumstances are vastly different from what they were in the late XNUMXth century, crop failures in multiple regions of the breadbasket still have the potential to affect global food availability," said study co-author Deepti Singh. , assistant professor at the WSU School. enviroment. “This, in turn, could increase the volatility of global food prices, affecting access to food and exacerbating food insecurity, particularly in regions that are already vulnerable to environmental shocks such as droughts.”

The researchers' analysis focused specifically on ten regions of the planet that receive most of their rain during June-September, have high variability in monthly summer precipitation, and are affected by variations in ENSO, factors that lead to increased potential for simultaneous drought. Several of the regions analyzed include important agricultural regions and countries currently facing food and water insecurity.

Their results indicate that the areas of North America North and South are more likely to experience compound droughts in a future climate warmer than regions in Asia, where much of the agricultural land is projected to become wetter.

Therefore, food produced in the Americas could be more susceptible to climate hazards. . For example, the United States is a major exporter of basic grains and currently ships corn to countries around the world. Even a modest increase in the risk of compounding droughts in future climate could lead to regional supply shortfalls which, in turn, could spill over into the global market, affecting global prices and amplifying food insecurity.

“The potential for a food security crisis increases even if these droughts do not affect the main food-producing regions, but rather many regions that are already vulnerable to food insecurity,” said co-author Weston Anderson, an assistant research scientist at the Center. Interdisciplinary Earth System Sciences. at the University of Maryland. “Simultaneous droughts in food-insecure regions could, in turn, increase strains on international disaster relief agencies by requiring the provision of humanitarian aid to larger numbers of people simultaneously.”

There is good news, Anderson said. The researchers' work is based on a scenario of high fossil fuel emissions, and in recent years the global community has moved towards reducing carbon emissions, which would greatly mitigate the frequency and intensity of simultaneous droughts by the end of the XNUMXst century.

Furthermore, the occurrence of almost 75% of composite droughts together with ENSO events in future climate highlights the potential to predict where these droughts may occur up to nine months in advance.

“This means that concurrent droughts during ENSO events will likely affect the same geographic regions as today, albeit with greater severity,” Deepti Singh said. "Being able to predict where these droughts will occur and their potential impacts can help society develop plans and efforts to minimize economic losses and reduce human suffering from such weather-induced disasters."

In the future, the researchers plan take a closer look at how simultaneous droughts will affect various aspects of the global food web , how vulnerable communities are affected by and adapt to such weather extremes, and how society can be better prepared to manage the risk of increased simultaneous disasters.

Project collaborators included researchers from WSU, Oak Ridge National Laboratory, the University of Massachusetts, Lowell, Columbia University, and the Indian Institute of Technology in Gandhinagar, India.

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