UMD Researchers and Alums Pioneer Innovative New Agricultural Productivity Analyses with Insight into Climate Change

Research integrates weather data and productivity calculations in U.S. agriculture, revealing the Midwest region as particularly vulnerable to climate change

Image Credit: Edwin Remsberg

February 18, 2019 Samantha Watters

UMD and Cornell researchers recently found that the changes in our U.S. agricultural industry, including a tendency to plant more specialized rain-fed crops like corn and soybeans, has made yearly outputs increasingly variable and more vulnerable to a changing climate. The Midwest region is particularly at risk due to their reliance on these types of crops and lack of access to water in increasingly common drought conditions. UMD’s Agricultural & Resource Economics is at the forefront of this work, pioneering new productivity calculations to include weather data in a way that hasn’t historically been addressed. This gives a clearer picture of the U.S. agricultural industry and what steps can be taken to prepare for future climate conditions.

“All agriculture is not the same across the country,” says Bob Chambers, professor in Agricultural & Resource Economics at UMD. “People outside the industry have a stylized image of the American farmer, but we want to show the broader representation of differences across the industry and factor weather into that picture.”

To get this big picture look at agriculture across the country, Chambers and Ariel Ortiz-Bobea, assistant professor of applied economics and management at Cornell University and a doctoral alumni of the UMD Agricultural & Resource Economics program, used state-level measures of agricultural productivity that capture how agricultural inputs like seeds, feed, fertilizer, equipment, and herbicides are translated into economic outputs. The researchers mapped that information against decades of climate data from 1960 through 2004, adding weather conditions as an additional input.

“The trends show that increases in concentrated and specialized crops are leading to greater vulnerability to weather events,” says Chambers.

“Most of the agriculture in the Midwest is corn and soybeans. And that’s even more true today than it was 40 years ago,” says Ortiz-Bobea. “That has implications for the resilience to climate of that region, because they’re basically putting all their eggs in one basket, and that basket is getting more sensitive.”

Chambers adds, “When a farmer makes an economic decision like what to plant in June, we won’t necessarily know the outcome of that decision until 6 months later. So there is a distinct break between input and output, and random events like weather can severely affect that. Productivity is essentially a calculation of your inputs compared to your outputs, and in most industries, the only way to get growth is with new inputs. Agriculture has had an average growth of 1.4 percent per year since 1948, which is staggering when you realize we haven’t had new inputs. This becomes dependant on technological advances and other major inputs, like weather and climate events that are increasingly erratic. Productivity hasn’t historically incorporated weather data, but we wanted to see the trends if we added these inputs that are out of the farmer’s control into the productivity calculations.”

The data pulled for this analysis were taken from the United States Department of Agriculture’s Economic Research Service, pioneered under V. Eldon Ball, a now-retired senior economist and also a doctoral alumni of UMD’s Agricultural & Resource Economics program. Ball is known for the design and implementation of the agency’s research program on agricultural productivity, and credited by USDA as “the singular driving force in leading the USDA to create a state-of-the-art system of official statistics on productivity that has served as a model in this important area of research.” It is only through this alum’s work at USDA gathering and processing the necessary national data that this comprehensive look at weather data and productivity is possible.

And the data are clear, highlighting increased climate sensitivity in the Midwest particularly and showing very troubling hits to productivity over time. For example, when the temperature increased 2 degrees over the summer in the 1960s and 70s, productivity dropped 11 percent. But after 1983, the same increase in temperature caused a productivity drop of 29 percent. These types of summers may not come along that frequently now, but an additional 1 degree in temperature has the potential to quadruple the frequency of these hot summers, meaning once every 4 years could lead to a summer with high productivity loss.

“If these things materialize like the climate models are saying, you would need to have a sustained growth in yields that will need to exceed the historical rates we’ve seen over the past several decades,” Ortiz-Bobea said. “Otherwise you would have to increase more inputs – more fertilizer, more land – in order to have the supply to meet the demand of our rising population. Because the changes are coming – changes in temperature, changes in precipitation, and at a different magnitude than what we’ve seen.”

“It’s not what we can do, but it is where we are headed,” emphasizes Chambers. “History has taught us that farmers know how to adapt to changing climates, but this gives us an idea of trends in what we’ve done in the past to help see what to do in the future with new changes in the climate that are beyond what we’ve previously seen. We are projected to have almost 10 billion people to feed by 2050, so making sure our productivity is not just stable but growing faster than ever before is a serious concern.”

Research is published in Science Advances. Also, watch a video produced by Cornell University further explaining the findings and implications of this work at