Limited freshwater for irrigation, coupled with projected climate change, could hurt crop production much more than previously thought, a report says.
Published in the Proceedings of the National Academy of Sciences, the study by research scientist Joshua Elliott and colleagues says that’s because a lack of water could force farmers globally to switch between 50 million and 150 million acres of irrigated land back to rain-fed production. The study (titled "Constraints and potentials of future irrigation water availability on agricultural production under climate change") is expected to improve the accuracy of future research because it uncovered "discrepancies in how hydrological models incorporate processes such as the carbon cycle and crop water productivity when compared to agricultural models," according to a summary published by the Computation Institute.
Additionally, the study attempts to quantify the caloric value of food that could be lost through water scarcity. Climate-change models have suggested a loss of 400 and 2600 petacalories per day (one petacalorie equals ten to the power of 15 calories), and the new report notes water scarcity could cut between 600 and 2900 petacalories more than that.
But don't worry: The news isn't all bad. Some places might have a water surplus that could limit the effect of climate change on food production by up to 57% if allocated properly.