Environmental changes, including climate warming, water scarcity and biodiversity loss, are projected to deepen in the 21st century, posing serious challenges.
Scientists at the London School of Hygiene and Tropical Medicine (LSHTM) for the first time systematically examined the impact of predicted environmental changes on the production and nutritional properties of common crops such as tomatoes, leafy vegetables and legumes.
The researchers estimate that environmental changes that are predicted to be achieved by the middle to the end of the century will reduce the average yield of vegetables and legumes by 35% and 9%, respectively. In the hot conditions of Southern Europe, Africa and South Asia, high temperatures will reduce yields by an average of 31%.
Previously, there was evidence of the negative impact of projected changes on yields of major crops such as rice and wheat. In the new study, the researchers systematically reviewed all the available evidence from experimental studies published since 1975 on the impact of environmental changes on the yield and nutritional properties of vegetables and legumes, important ingredients in a healthy diet. The review included the results of experiments carried out in 40 countries.
The team then assessed the impacts on crops of major environmental factors, including increased concentrations of greenhouse gases (tropospheric carbon dioxide and ozone), water scarcity for irrigation, and rising temperatures due to global warming.
Previous studies have shown that increased carbon dioxide levels will lead to increased crop yields, but this study has shown for the first time that such an outcome is unlikely given other accompanying environmental changes. The authors warn that, if not responded to, the elimination of vegetables and legumes from the diet could have a significant impact on the health of populations around the world.
The research is published in Proceedings of the National Academy of Sciences.
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