Extreme Heat Threatens Crop Prospects Around the World

Severe heat waves around the world look set to notch July 2023 as the planet’s hottest month ever recorded.  

From the US to Europe and northern China, hot, dry conditions at times have turned deadly. The extreme weather also is taking a toll on agricultural crops across the Northern Hemisphere and could exacerbate worldwide food insecurity if conditions don’t improve during the rest of the growing season. 

Temperature records for the globe were broken on three successive days in early July, and there’s been little respite since. The intense heat is being attributed to a combination of greenhouse-gas-induced climate change together with the normal return of El Niño, a cyclical climate pattern that tends to bring overall warmer temperatures. 

Heat advisories have been posted throughout the US Corn Belt on Thursday, with triple-digit temperatures expected to reach as far north as South Dakota. The key corn growing states of Iowa and Illinois will be in the high 90 degrees Fahrenheit (35-plus degrees Celsius). 

Although rainfall totals for US corn regions are below the historical average, as seen with Gro’s Climate Risk Navigator for Agriculture, Gro’s vegetative health index continues to signal a strong crop, as the hot weather hastens plant growth. That could reverse, however, if recent declines in soil moisture push Gro Drought Index readings higher and damage yields as corn plants continue their critical development stage into August. 

Gro’s US Corn Yield Forecast Model, which predicts yields down to the county level, is currently forecasting overall corn yield will be higher than last year after record amounts of rainfall reversed early season extreme drought conditions. Critical growing stages lie ahead. If recent declines in soil moisture push Gro Drought Index readings higher, we could see the yield outlook erode once again.

View this display from the Gro Climate Risk Navigator showing near-real-time precipitation and soil moisture levels, as well as drought index and vegetative health index readings, weighted for US acres planted to corn. 

US heat waves have been most intense in the Southern states. Land surface temperatures in Texas’ cotton-growing regions have exceeded 95 degrees Fahrenheit (35C) consistently since mid-June. The sweltering heat is now affecting the state’s cotton prospects, as Gro wrote about here. Current soil moisture levels are among the lowest in over 20 years, and less than a quarter of the crop is currently rated “good-to-excellent.” 

European wheat and other crops also are suffering under extreme conditions. For France and Germany, the Gro vegetative health index, weighted for the two countries’ cropland areas, is at one of the lowest levels for this time of year since the start of the century, as seen in this Gro Navigator display. The same display shows that the Gro Drought Index is at a two-decade high, and that GFS forecasts are calling for minimal precipitation over the next two weeks. 

Russia, the world’s biggest wheat exporter, produced a bumper winter wheat crop. But hot and dry conditions are now threatening the country’s spring wheat — Gro’s vegetative health index is near a historical low, and Gro Drought Index readings are close to “extreme” levels, as seen in this Gro Navigator display weighted for Russia’s principal spring-wheat growing regions.  

Heat-compromised wheat crops in Russia, Europe, and other regions could further limit supplies for import-dependent countries, including in North Africa, the Middle East, and Asia. Russia’s renewed blockade of Ukrainian ports also is contributing to tighter global grain supplies, as Gro wrote about here.  

In China, the world’s No. 1 cotton producer and importer, searing heat broke the country’s all-time national high temperature at 126 degrees Fahrenheit (52.5 Celsius) earlier this month in Xinjiang province, where the bulk of China’s cotton is grown. Xinjiang soil moisture readings, weighted for cotton growing areas using the Gro Navigator, are the lowest since at least 2010 and the Gro Drought Index is close to “extreme” levels.  

While cotton is more heat-tolerant than many other plants, excessive temperatures during its reproductive phase can increase boll shedding and lower yields. With cotton crops threatened by excessive heat in both China and Texas, cotton prices have been rising — the December ICE contract was up 5% so far this month, reaching a new contract high before giving up some gains today on apparent profit-taking.