When it comes to variations in crop yield, climate has a big say

January 22, 2015
The connection between climate and yield variability differs around the world. It is strongest in the red areas and weakest in the light green and gray areas. Credit: University of Minnesota Institute on the Environment

What impact will future climate change have on food supply? That depends in part on the extent to which variations in crop yield are attributable to variations in climate. A new report from researchers at the University of Minnesota Institute on the Environment has found that climate variability historically accounts for one-third of yield variability for maize, rice, wheat and soybeans worldwide—the equivalent of 36 million metric tons of food each year. This provides valuable information planners and policy makers can use to target efforts to stabilize farmer income and food supply and so boost food security in a warming world.

  • The work was published today in the journal Nature Communications by Deepak Ray, James Gerber, Graham MacDonald and Paul West of IonE's Global Landscapes Initiative.
  • The researchers looked at newly available production statistics for maize, rice, wheat and soybean from 13,500 political units around the world between 1979 and 2008, along with precipitation and temperature data. The team used these data to calculate year-to-year fluctuations and estimate how much of the yield variability could be attributed to .
  • About 32 to 39 percent of year-to-year variability for the four crops could be explained by climate variability. This is substantial—the equivalent of 22 million metric tons of maize, 3 million metric tons of rice, 9 million metric tons of wheat, and 2 million metric tons of soybeans per year.
  • The links between climate and yield variability differed among regions. Climate variability explained much of yield variability in some of the most productive regions, but far less in low-yielding regions. "This means that really productive areas contribute to food security by having a bumper crop when the weather is favorable but can be hit really hard when the weather is bad and contribute disproportionately to global food insecurity," says Ray. "At the other end of the spectrum, low-yielding regions seem to be more resilient to bad-weather years but don't see big gains when the weather is ideal." Some regions, such as in parts of Asia and Africa, showed little correlation between climate variability and yield variability.
  • More than 60 percent of the yield variability can be explained by climate variability in regions that are important producers of major crops, including the Midwestern U.S., the North China Plains, western Europe and Japan.
  • Depicted as global maps, the results show where and how much climate variability explains yield variability.

The research team is now looking at historical records to see whether the variability attributable to climate has changed over time—and if so, what aspects of climate are most pertinent.

"Yield variability can be a big problem from both economic and standpoints," Ray said. "The results of this study and our follow-up work can be used to improve food system stability around the world by identifying hot spots of insecurity today as well as those likely to be exacerbated by in the future."

Explore further: Global warming reduces wheat production markedly if no adaptation takes place

More information: Nature Communications, www.nature.com/ncomms/2015/150 … full/ncomms6989.html

Related Stories

Global precipitation variability decreased from 1940 to 2009

October 29, 2012

One of the strongly held assumptions of climate change is that the variability of precipitation will grow with an increase in temperature. Storms will become heavier but less frequent. Flash floods and droughts will increase. ...

Central European summer temperature variability to increase

December 18, 2012

More extreme heat waves have been observed in central Europe in recent years as summer temperature variability has increased on both daily and interannual timescales. Models project that as the climate warms throughout the ...

Climate forecasts shown to warn of crop failures

July 22, 2013

Climate data can help predict some crop failures several months before harvest, according to a new study from an international team, including a research scientist at NASA's Goddard Space Flight Center in Greenbelt, Md.

Recommended for you

New magma pathways after giant lateral volcano collapses

October 23, 2017

Giant lateral collapses are huge landslides occurring at the flanks of a volcano. Giant lateral collapses are rather common events during the evolution of a large volcanic edifice, often with dramatic consequences such as ...

Scientists warn that saline lakes in dire situation worldwide

October 23, 2017

Saline lakes around the world are shrinking in size at alarming rates. But what—or who—is to blame? Lakes like Utah's Great Salt Lake, Asia's Aral Sea, the Dead Sea in Jordan and Israel, China's huge Lop Nur and Bolivia's ...

Mountain glaciers shrinking across the West

October 22, 2017

Until recently, glaciers in the United States have been measured in two ways: placing stakes in the snow, as federal scientists have done each year since 1957 at South Cascade Glacier in Washington state; or tracking glacier ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.