Flash droughts develop fast, and when they hit at the wrong time, they can devastate a region’s agriculture. They’re also becoming increasingly common as the planet warms.
In a new study published May 25, 2023, we found that the risk of flash droughts, which can develop in the span of a few weeks, is on pace to rise in every major agricultural region around the world in the coming decades.
In North America and Europe, cropland that had a 32 percent annual chance of a flash drought a few years ago could have as much as a 53 percent annual chance of a flash drought by the final decades of this century. The result would put food production, energy and water supplies under increasing pressure. The cost of damage will also rise. A flash drought in the Dakotas and Montana in 2017 caused $2.6 billion in agricultural damage.
In our new study, we used climate models and data from the past 170 years to gauge the drought risks, and found that if greenhouse gas emissions from vehicles, power plants and other human sources continue at a high rate, cropland in much of North America and Europe would have a 49 percent and 53 percent annual chance of flash droughts, respectively, by the final decades of this century. Globally, the largest projected increases would be in Europe and the Amazon.
Slowing emissions can reduce the risk significantly, but we found flash droughts would still increase by about 6 percent worldwide under a low-emissions scenario.
If a flash drought occurs at a critical point in the growing season, it could devastate an entire crop.
One way to help agriculture adapt to the rising risk is to improve forecasts for rainfall and temperature, which can help farmers as they make crucial decisions, such as whether they’ll plant or not.
When we talk with farmers and ranchers, they want to know what the weather will look like over the next one to six months. Meteorology is pretty adept at short-term forecasts that look out a couple of weeks, and at longer-term climate forecasts using computer models. But flash droughts evolve in a midrange window of time that is difficult to forecast.
We’re tackling the challenge of monitoring and improving the lead time and accuracy of forecasts for flash droughts, as are other scientists. For example, the United States Drought Monitor has developed an experimental short-term map that can display developing flash droughts. As scientists learn more about the conditions that cause flash droughts and about their frequency and intensity, forecasts and monitoring tools will improve.
Increasing awareness can also help. If short-term forecasts show that an area is not likely to get its usual precipitation, that should immediately set off alarm bells. If forecasters are also seeing the potential for increased temperatures, that heightens the risk for a flash drought developing.
Nothing is getting easier for farmers and ranchers as global temperatures rise. Understanding the risk from flash droughts will help them, and anyone concerned with water resources, manage yet another challenge of the future.
This article was excerpted from a report written by Jeff Basara, chair of the department of environmental earth and atmospheric sciences at the University of Massachusetts Lowell, and Jordan Christian, postdoctoral researcher in meteorology at the University of Oklahoma. Read the full report, published by The Conversation, a nonprofit news service, here.