GAINESVILLE, Fla. — With a global need for more food, a worldwide team of scientists led by a University of Florida professor has found that with each degree of Celsius that the Earth warms, humans stand to lose more wheat, rice, maize and soybeans over the next 30 years.
In fact, average yields will go down for maize by 7.4 percent; wheat by 6 percent; rice by 3.2 percent; and soybeans by 3.1 percent for each degree in global warming, according to a new study published in the Proceedings of the National Academy of Sciences. Those figures are global averages and vary by the geographic location on Earth.
Scientists, led by Senthold Asseng, a UF professor of agricultural and biological engineering, compared four scientific methods to come to their temperature impact assessments. The team assessed the impact of increasing temperatures on yields of the four crops by analyzing more than 70 studies. The meta-analysis included studies that incorporated process-based model simulations of yield response to temperature changes at the global and local scale, statistical regression models based on historical weather and yield data and artificial field warming experiments.
By combining the methods, the researchers’ assessment of the effects of increasing temperatures on major global crops shows substantial risks for agricultural production, said Asseng, a faculty member at the UF Institute of Food and Agricultural Sciences. Farm production is already stagnating in some parts of the world, he said.
“However, differences in how crops respond to increasing temperatures suggest some adaptation could be possible to substantially affect the magnitude of climate change impacts on agriculture,” Asseng said. “Adaptations to rising temperature could include changing sowing dates and cultivars. A long-term strategy should include breeding for new cultivars, which are more tolerant to high temperatures.”
Because impacts from global warming vary with crop and region, adaptation strategies need to be specific within a region to be successful, he said.
Wheat, rice, maize and soybeans provide two-thirds of human caloric intake, according to the study. So assessing global temperature increases on production of these crops will help maintain global food supply, Asseng said.
The crops assessed in the new study help feed a world population scientists project will reach 9.5 billion people by the year 2050. UF students are working on a project known as Challenge 2050, an interdisciplinary curriculum designed to see what solutions they can develop to solve the projected global hunger deficit. UF/IFAS is leading the Challenge 2050 effort.
Crops are sensitive to climate change, including variations in temperature, precipitation and rising atmospheric carbon dioxide, according to a 2014 study led by NASA researchers. Among the changes, temperature increase has the most likely negative impact on crop yields.
“By better understanding the impacts of climate change, we can explore specific adaptation strategies to minimize negative consequences,” Asseng said. “This assists policy makers with science-based evidence to develop research investment strategies and prepare for future hot spots of food security, knowing that food security is often linked to global security.”
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