Scientists investigated the potential for producing more food with the same amount of water by optimising rain use and irrigation.

As global warming is expected to worsen droughts and change rainfall patterns, water availability becomes even more crucial in reducing threats to the global food supply.

"Smart water use can boost agricultural production – we've in fact been surprised to see such sizeable effects at the global level," said Jonas Jägermeyr from the Potsdam Institute for Climate Impact Research, the study's lead author. "It turns out that crop water management is a largely underrated approach to reduce undernourishment and increase climate resilience of smallholders."

In the most ambitious scenario, global calorie production could rise by 40 percent, halving the global food deficit by 2050, even though the world's population is forecast to reach 9.7 billion people by then, up from 7.3 billion now.

Even in less ambitious scenarios, the results show that integrated crop water management could make a crucial contribution to filling the plates of the poor, Jägermeyr said.

Using computer simulations, the scientists investigated different water management options, from low-tech solutions such as collecting rainwater in cisterns to mulching and industrial-scale drip irrigation.

The potential for yield increases through crop water management is particularly large in water-scarce regions in China, Australia, the western United States, Mexico and South Africa, the study found.

"Water management is key for tackling the urgent global sustainability challenge," said Johan Rockström, co-author of the study and director of the Stockholm Resilience Centre.

But in a business-as-usual scenario – if greenhouse-gas emissions from burning fossil fuels are not reduced at all – water management will clearly not suffice to outweigh the negative effects of climate change, the study said.

Reporting by Astrid Zweynert, editing by Tim Pearce of the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, which covers humanitarian news, women's rights, trafficking, property rights and climate change. Visit: news.trust.org