As the world turns, corn drops down

Climate change is going to have profoundly different impacts on two of the world’s most widely grown cereal crops, according to new research.

Global corn yields are projected to decline by 24 percent by the end of the century, while wheat yields are forecast to grow by 17 percent over that same period, according to a recently published international study.

The study was conducted by scientists from the International Institute for Applied Systems Analysis (IIASA), NASA and the Potsdam Institute for Climate Impact Research.

The team created about 240 global climate crop model simulations for each crop.

“We did not expect to see such a fundamental shift as compared to crop yield projections from the previous generation of climate change and crop models conducted in 2014,” said lead author Jonas Jaegermeyr, a crop modeler and climate scientist at NASA’s Goddard Institute for Space Studies.

The main explanation for the stark contrast in corn and wheat yield projections is that wheat is grown across higher latitudes, while corn is grown mainly in tropical and subtropical countries.

“Generally speaking, climate change impacts on crops will be most severe at lower latitudes where additional warming will push crops closer or beyond critical temperature thresholds,” Jaegermeyr said in an email.

“For high latitude wheat cultivation, additional warming can actually be beneficial in some cases.”

The other main contributing factor to the difference is that wheat is a C3 crop that can benefit from higher carbon dioxide levels much more than corn and other C4 crops.

“Much of the wheat gains the models project under high-emission pathways are linked to a strong carbon dioxide fertilizer effect,” he said.

Other western Canadian crops such as barley, canola and pulses are also C3 crops and have the capacity to benefit from higher carbon dioxide concentrations similar to wheat.

Jaegermeyr was particularly shocked by the “surprisingly large” drop in corn yields.

“A global reduction by 24 percent is of unprecedented scale, which, if unabated, would have significant cascading affects for the global food system and for regional food security,” he said.

On the wheat front, he expects to see an expansion of cultivated areas into colder zones at higher latitudes in Canada, Europe and Russia.

Canadian spring wheat yields are expected to increase by 10 to 15 percent by the end of the century under unabated climate change.

The gains in global wheat production will not fully compensate for the losses in corn.

But more importantly, wheat and corn are generally grown in different locations of the world. Corn is a staple food crop for many small farmers in tropical and subtropical regions and they can’t offset a 24 percent reduction in yields by switching to growing wheat.

Jaegermeyr said the models show the impact of climate change started around 2017 for corn and right around now for wheat.

Wade Sobkowich, executive director of the Western Grain Elevator Association, had a succinct way of summing up the ramifications of the study findings.

“I guess we’re eating more flour tortillas and less corn tortillas,” he said with a chuckle.

But in all seriousness, there could be some pretty profound implications for his member companies and the farmers who supply them.

He believes it would be a net positive impact because there is a lot more wheat grown in Western Canada than corn. Grain companies make more money when there is more product running through their facilities.

“That’s what they do. They buy grain, they move grain and they sell grain,” he said.

Sobkowich said grain companies are already noticing that wheat and canola yields have been on the rise the past eight or nine years, with the notable exception of this year due to drought.

“It sounds like maybe we could continue to see some extra growth in production in years to come,” he said.

Sylvain Charlebois, director of the Agri-Food Analytics Lab at Dalhousie University, thinks the projected massive drop in corn yields might not be that big of a deal.

“Honestly, I’m not sure it’s going to be an issue just because of the shift we’re seeing in proteins right now,” he said.

A lot of corn goes into the feed market but he thinks demand for animal protein is going to be stagnant at best over the coming years.

“Today I’m in meetings with investors and I’ve got to tell you, the money is going towards vegetable protein — like, a lot,” said Charlebois.

His concern with rising wheat yields is that it may drive prices down because wheat demand isn’t that strong. Food companies are far more interested in crops like pulses and canola, he said.

Charlebois wonders if the forecast 24 percent drop in corn yields might be a bit overblown because crop breeders and seed technology companies have shown they are pretty skilled at offsetting some of the negative impacts of climate change.

Jaegermeyr acknowledged that the study deliberately excluded adaptation measures so it could isolate the impact of climate change.

Adaptation measures include factors like shifting planting dates, using better adapted cultivars or switching to other crops.

“Implementing these measures has the potential to buffer much of the adverse impacts the models simulate but they will also help realize and expand gains we see in higher altitudes,” he said.