UF researchers find wheat production models disagree under climate change scenarios

June 10, 2013

GAINESVILLE, Fla. — University of Florida researchers have found, for the first time, that crop models predicting yields for one of the world’s most important crops begin to disagree under climate change scenarios.

By knowing where those models break down, researchers will be better able to improve them. The computerized models predict crop yields for wheat, one of the world’s most-consumed foods.

Scientists use crop models to foresee which parts of the world may face the greatest food shortages, so that efforts to improve food production can be directed to those places.

The researchers made the discovery by analyzing the effectiveness of 27 wheat models created by top scientists from around the world under both normal and climate change conditions. Their results are reported in a study published online this week by the journal Nature Climate Change.

“What we found was that, if you gave them enough information, there are a lot of models that can reproduce experimental data very well,” said Senthold Asseng, an associate professor in the UF agricultural and biological engineering department and the study’s lead author.

“But when it comes to climate change, when we start manipulating the climate data similarly to how climate change will play out in the next 50 to 100 years, the models started to disagree more and more,” said Asseng, a faculty member in UF’s Institute of Food and Agricultural Sciences. “And they started to disagree, particularly with increasing temperatures and carbon dioxide.”

Wheat, which accounts for 20 percent of calories consumed globally, is one of the world’s three most important crops, along with rice and maize.

In the past 100 years, global temperatures have risen by more than 1 degree Fahrenheit, according to the U.S. Environmental Protection Agency. Carbon dioxide levels in the atmosphere have increased by nearly 27 percent in the last 55 years to 400 parts per million, the highest level in about 2.5 million years, according to the Scripps Institution of Oceanography.

Jim Jones, an emeritus distinguished professor in the UF/IFAS agricultural and biological engineering department and a co-author of the study, said crop models are essential for pulling information from many different sciences into one place.

“As agricultural scientists we need to have an understanding of how our food systems are going to respond to the future challenges associated with climate change,” Jones said.

Ken Boote, another co-author of the study and emeritus professor in the UF/IFAS agronomy department, said researchers are now working together to improve their models using information such as new temperature data from different areas of the world.

The research is part of AgMIP, or the Agricultural Model Intercomparison and Improvement Project, an international effort to assess crop models and understand climate change’s impact on food production.

UF is one of three organizations, including the NASA Goddard Institute for Space Studies in New York City and the U.S. Department of Agriculture, leading the AgMIP project.

Principal investigators for AgMIP are Cynthia Rosenzweig, based at the Goddard Institute, Jones with UF/IFAS and Jerry Hatfield with the USDA’s Agricultural Research Service.

Asseng coordinated the wheat study with co-author Frank Ewert, a professor with the Institute of Crop Science and Resource Conservation at the University of Bonn in Germany, and worked with scientists from 15 countries to conduct the research.