World Environment Day: Study flags drought and heat threatens global breadbaskets

05 Jun 2023 --- Heat waves that used to occur once per century now happen every six years in the Midwestern US and every 16 years in Northeastern China, according to a new study by researchers from the Friedman School of Nutrition Science and Policy at Tufts University, Massachusetts, US.

“Malnutrition will only worsen if we allow that to happen,” Erin Coughlan de Perez, a professor at the Friedman School of Nutrition Science at Policy at Tufts University, tells NutritionInsight.

“Extreme heat and drought could devastate agricultural production. There are many agricultural adaptation opportunities to prepare for this, including developing and planting heat-resistant varieties, changing agricultural locations, and shifting schedules.”

The study, published in Climate and Atmospheric Science, notes that according to a recent report by the Intergovernmental Panel on Climate Change, the average global surface temperature was 1.1 degrees Celsius warmer in the last decade compared to between 1850 and 1900.

By 32.8 degrees Celsius and above, crucial enzymes in the wheat start breaking down.By analyzing seasonal forecasts from the last 40 years, scientists say they can estimate the frequency and likelihood of extreme temperatures beyond wheat’s growth threshold.

Underestimating risks
Wheat that starts its growth in the fall is harvested in the following summer, and hot temperatures during spring can significantly affect crop development. The plants begin to suffer from heat stress above 27.8 degrees Celsius, and by 32.8 degrees Celsius and above, crucial enzymes start breaking down.

“In the Midwest, we used to have seasons where you’d see an average of maybe four or five days of that enzyme breakdown threshold being exceeded – it was pretty uncommon. But, our research showed possible alternative realities of today’s climate that generated 15 days above this threshold, which we surmise would be very damaging.”

Record heat also results in a record drought, impacting the growing season. China and the US are both considered “global bread baskets” and would therefore lead to global price increases and food insecurity if crops fail. 

“The historical record is no longer a good representation of what we can expect for the future,” says Coughlan de Perez. “We live in a changed climate and people are underestimating current-day possibilities for extreme events.”

“Climate change is happening on top of many other factors that can increase the price of wheat – such as changes to exports – and high food prices can cause major food insecurity in much of the developing world. The combination of climate extremes and other factors could cause the largest price spikes in the future.” 

Climate and food shortages
The World Food Program has been forced to shut down aid programs because of high food prices and lack of funding, making the international organization incapable of feeding the increasing number of food-insecure nations.

“We can also help avoid price shocks from failed harvests by building resilient and diverse food systems globally. To avoid the negative impact of high food prices on vulnerable communities, we must invest in food access and social protection systems to ensure that people have nutritious and appropriate food,” Coughlan de Perez adds.

The European State of Climate reported 2022 as the continent’s second warmest year and the warmest summer with the lowest levels of rain and snowfall ever.  

“If we only look at the past to understand possible future disasters, we will drastically underestimate current and future risks. Therefore, we need to use climate science to update our risk perception and to be able to imagine the unimaginable, revealing unprecedented climate events that are possible today, which would have dire consequences for agriculture,” outlines Coughlan de Perez.

Random luck?
The scientists explain that both regions have been lucky in the last couple of years, accounting for the randomness of weather as both areas have had lower temperatures than they could have had.

Meanwhile, the researchers also identified regional and global circulation patterns that might cause severe heat and drought, affecting China and the US in the same season. To avoid price shocks from failed harvests, we should build resilient and diverse global food systems.

“I think, with climate change, we’re suffering from a failure of imagination. If we’re not imagining the extremes that could happen, we won’t prepare for them. We don’t have to be surprised. We can use tools to understand what’s possible and be ready when it happens,” Coughlan de Perez notes.

A study from last year showed how climate change and extreme heat drive child malnutrition and poor economic outcomes.

“We show that average heat exposure in our study region increases the prevalence of acute and chronic malnutrition. What’s concerning about this is that as temperatures rise, more children will be exposed to these dangerous levels of extreme heat,” Sylvia Bloom, a development economist and researcher, previously told NutritionInsight.

Coughlan de Perez concludes that climate risk management can use storylines of record-breaking climate events to help people grasp the potential impacts without having to experience them firsthand. 

“Collaboration between countries like China and the US can help inspire climate change adaptation and build resilient food systems.”

By Beatrice Wihlander