The state of Illinois is suffering from its driest conditions in more than a decade. In fact, large swathes of the Midwest and Plains states are suffering from extraordinarily dry conditions according the U.S. Drought Monitor.
But a certain kind of drought is becoming more and more frequent: flash drought. The U.S. National Oceanic and Atmospheric Administration defines flash drought as follows:
Flash drought is simply the rapid onset or intensification of drought. It is set in motion by lower-than-normal rates of precipitation, accompanied by abnormally high temperatures, winds, and radiation. Together, these changes in weather can rapidly alter the local climate.
Illinois had been suffering from flash droughts since mid-April when virtually none of the state suffered from drought conditions.
Flash droughts are occurring more frequently than in the past, probably due to climate change. Researchers are not yet saying that this is the new normal since “slow droughts may also increase.” This change in the frequency of flash droughts “challenges drought monitoring and forecasting capabilities.” We’ll be less able to cope because models used previously to forecast drought will not work as well.
Droughts of any kind have consequences. In this case the consequences may be substantial for food crops such as corn, soybeans and wheat which are grown in large quantities in areas hit by drought so far this year. They represent three of the four main food crops which also include rice. Drought currently affects 64 percent of the U.S. corn crop and 57 percent of the soybean crop. So-called winter wheat, planted in the fall and harvested the following summer, may have suffered as well. The winter wheat harvest is just beginning.
Across the world in Asia, rice is in good supply, but rice-growing nations are wondering whether the emerging El Nino, a warming of the water in the southern Pacific Ocean, will reduce rainfall to India and southeast Asia as it often does. Some farmers in the Philippines are reluctant to plant rice fearing El Nino may hurt the water-intensive crop.
When drought hits wheat stands, they develop fewer harvestable heads and empty kernels. Corn develops what is called “leaf rolling” in which the leaves roll up to reduce water loss. But this also reduces photosynthesis and thus production of corn. Potassium deficiency is often a symptom of drought for corn. At a certain stage kernel rows will be reduced and the number of kernels per row will be limited.
Soybeans under drought stress can lose blossoms and pods and/or have both reduced seed numbers and size.
Grains may seem like a substantial, but not overly large part of the human diet. But it is important to remember that grains and oilseeds such as soybeans make up almost all of the feed for dairy, meat and egg-producing animals and are important sources of cooking oils. Hence, they are the basis of the vast majority of calories humans consume each day.
Droughts of the slow and fast kind are becoming more frequent. For those of us living in the city, clear skies might seem like a blessing in summer as long as it is not too hot. But to farmers clear skies with no rain day after day are a known danger to crop yields. Given the accelerating pace of climate change, drought and threats to crop yields are likely to move from being an occasional concern every few years to a frequent concern. And, that could challenge the very structure and viability of the worldwide food system we have built.
Image: Ploughing and seeding wheat in the American West (1881) From the book “Our American West” by L. P. Brockett. Via Wikimedia Commons https://commons.wikimedia.org/wiki/File:Our_western_empire,_or,_The_new_West_beyond_the_Mississippi_-_the_latest_and_most_comprehensive_work_on_the_states_and_territories_west_of_the_Mississippi_-_containing_the_fullest_and_most_complete_(14573813707).jpg
