With climate change shifting precipitation patterns, irrigation can be a powerful tool for increasing the world’s food supply, which could help in feeding more than a billion additional people without converting natural spaces into farmland, said a new study.
In the study published in Environmental Research Letters, Camegie’s Lorenzo Rosa found that sustainable irrigation that relies on groundwater and local available water sources can be used without depleting them beyond what precipitation can replace or harming freshwater ecosystems. Noting that population trends indicate that double global food production was needed by 2050, he said that this would either need to clear more land or farm more efficiently, despite the increased stresses of a warming world.
Converting undeveloped land into farms exacerbates climate change and decreases biodiversity. However, low crop yields in existing farmland can be improved by modern technology, the study said. Currently, two-thirds of the world’s crops are limited by rainfall. Climate change is expected to shift precipitation patterns and increase heat stress on plants, meaning that relying on rain alone will not keep up with the increased demand for food.
Several studies have shown that irrigated crops are twice as productive as those that rely on rainfall alone. However, irrigation already accounts for between 85 and 90 percent of human water consumption. Rosa found that under current conditions, there is enough water available from local, renewable sources to expand sustainable irrigation over 35 percent of farmland around the world, boosting crop productivity to feed 1.4 billion more people. However, climate change will make this calculus more complex. As the world warms, Rosa’s analysis indicates that in addition to heat. stress and changes in rainfall, climate change could also make water evaporate faster, decreasing the efficiency of irrigation. On the other hand, elevated levels of atmospheric carbon dioxide could make crops grow somewhat more productively, which might offset this concern. All these competing factors mean that additional research is needed to comprehensively understand the feasibility of sustainable irrigation for increasing food production. That said, Rosa’s study indicates that constructing long-term water storage reservoirs could enable sustainable irrigation to feed 1.2 billion more people than relying on renewable water resources alone.
He also mentioned that United States, Russia, Brazil, and Nigeria have the greatest potential for sustainable irrigation under extreme warming conditions using water storage facilities, although these types of programs will also be feasible in Latin America, Eastern Europe, and Sub-Saharan Africa.