A Warming World Could End Your Sandwich Habit

Scientists find that wheat production will plunge as global temperatures rise.

(Photo: Ever So Fine/Getty Images)

Jan 14, 2015· 1 MIN READ
Kristine Wong is a regular contributor to TakePart and a multimedia journalist who reports on energy, the environment, sustainable business, and food.

As the world warms, its wheat fields are withering.

That’s according to the latest research, which has found that one of the world’s most gobbled grains would decrease by 6 percent for every degree Celsius in temperature increase.

To put that in perspective, about 42 million tons of wheat would vanish if global temperatures increased just 1 degree Celsius. This isn’t a problem we’ll be facing years down the road. Warmer temperatures have already cut down yields in the majority of wheat-growing regions, according to researchers.

“This has significant implications for global food security,” said Senthold Asseng, a professor at the University of Florida’s Institute of Food and Agriculture Sciences and lead author of the study, published in the journal Nature Climate Change.

Here’s the problem. By 2100, the Intergovernmental Panel on Climate Change projects that global temperatures will rise by 2 to 4 degrees Celsius. By 2050, the world population is projected to hit 9.6 billion—an increase of 38 percent. That means more people and less food.

“Global food production, with wheat accounting for 20 percent of calories consumed globally, needs to grow 60 percent by 2050,” Asseng said. “That’s a huge agricultural challenge complicated by temperature increases due to climate change.”

Looking at 30 wheat varieties grown in a range of temperatures, researchers found that higher temperatures decreased yields.

Asseng explained: “Increasing temperatures reduces the time from sowing to maturity, which reduces the time a crop can photosynthesize, resulting in less growth and lower yields.”

Sticking those findings in a new computer-simulation model showed that this dynamic is already in play worldwide.

“When applying the multimodel ensemble globally, we found that warming is already slowing yield gains, despite observed yield increases in the past, at a majority of wheat-growing locations across the globe,” Asseng said.

Low-latitude areas are the most vulnerable because temperatures are already higher in these regions, he added.

The results aren’t surprising. Last year, researchers predicted that in Europe—the world’s largest producer of wheat—adverse weather related to climate change would be more likely to increase over the next 45 years and threaten production.

In 2012, researchers at the University of Gothenburg in Gothenburg, Sweden, found that higher carbon dioxide levels in the atmosphere decreased the amount of protein in wheat. Why? The increased amount of CO2 stunted the plants’ ability to absorb nitrogen during growth.

So what can be done to stop the slowdowns—or, in other words, adapt wheat production to climate change?

“New heat-tolerant wheat cultivars and crop management are needed to counteract the projected yield decline due to increasing temperature,” Asseng said.

At Kansas State University and at Texas A&M University, efforts are already under way to improve wheat’s heat tolerance. At Purdue University, researchers are developing corn that can be grown in the warmer climates of India, Pakistan, Bangladesh, and Nepal.

These types of global collaborations are what’s needed to gain a better understanding of climate change’s impacts on agriculture, Asseng said.