A quarter of the world’s harvests threatened if agriculture does not adapt to climate change

Credit: Ca ‘Foscari University of Venice

Changes in weather patterns induced by climate change will increase extreme heat and reduce rainfall in major growing regions, with impacts on agricultural production. Will this trigger a drop in the supply of calories needed to support the growing world population?

According to a study published in the Journal of Environmental Economics and Management, global caloric supplies are subject to continued, if not growing, vulnerability to climate change. Climate change could reduce global crop yields by 10% by mid-century and 25% by the end of the century, in a vigorous warming scenario, if farmers cannot adapt better than they do. ‘before.

To quantify this, a team of researchers from Boston University, Ca ‘Foscari University in Venice and the Euro-Mediterranean Center on Climate Change (CMCC) coupled their statistical models trained on past data with forecasts. of future temperature and precipitation data from 21 Global Climate Model (GCM) simulations to project how yields might change in response to climate change.

“Globally, the ability of farmers to adapt to the impacts of climate change, even over longer periods of time, may be limited,” says Professor Ian Sue Wing of Boston University and lead author of the Even in the United States, the global frontier in agricultural technology, farmers were only able to slightly offset the damaging effects of extreme heat on corn and soybean yields over decades of periods. “

Enrica De Cian, professor at Ca ‘Foscari University and researcher at CMCC adds: “We asked ourselves: if adaptation difficulties are observed in the United States, what then can we expect for food producers in the United States? tropics, where 40% of the world’s population are extreme temperatures and high temperatures expected to increase more than in the major calorie-producing regions of the United States?

The study sheds new light on this question. The authors analyze the global vulnerability of four crops (corn, rice, soybeans and wheat), responsible for 75% of global calorie intake, to future changes in temperature and precipitation caused by climate change.

“We used statistical models trained on large global gridded datasets of historical crop yields, temperature and precipitation, to separate changes in yield responses to heat and humidity exposure. during their crop-specific growing seasons into two types of adaptation – Malcolm Mistry, postdoc at Ca Foscari University in Venice and a research affiliate at CMCC, explains: On the one hand, the short-term response of farmers to unforeseen climatic shocks and, on the other hand, long-term adjustments over decades.

While farmers have limited options for adapting to short-term climate change – for example, by changing the amount of fertilizer or irrigation water applied to their crop – over long periods of time, it is possible for them to to undertake a substantial adaptation by changing the culture. varieties, change planting and harvest dates, adopt new agricultural technologies and invest in more or different agricultural machinery. In principle, long-term adjustments have the potential to offset the effects of inclement weather on yields.

The research question is: Have farmers really realized this potential?

“Surprisingly, globally and in most parts of the world, the answer is no,” says Professor Enrica De Cian. Our results showed that the detrimental effects of extremely hot or dry days on the productivity of the crops from which we derive food calories persisted for decades, in line with previous findings for the United States. Worse yet, these long-term negative effects were sometimes greater than the yield impacts that occurred due to transient climatic shocks.

“The implication is that global caloric supplies are subject to continued or even increasing vulnerability to climate change – concludes Professor Ian Sue Wing -. We now plan to build on these findings to investigate how investments in irrigation and shifting cultivation in space can help offset the impacts of adverse climate change.

Damaging impacts of moderate warming by the migration of rainfed crops

More information:
Ian Sue Wing et al, Global Vulnerability of Crop Yields to Climate Change, Journal of Environmental Economics and Management (2021). DOI: 10.1016 / j.jeem.2021.102462

Provided by Ca ‘Foscari University of Venice

Quote: A quarter of global harvests threatened if agriculture does not adapt to climate change (2021, June 11) retrieved June 11, 2021 from https://phys.org/news/2021-06-quarter-global-harvests -agriculture-climate .html

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