We’re all heard of flash floods – flooding that happens within hours after a large amount of rains falls in a short period. But the opposite phenomenon has been making the headlines lately: flash droughts.
Compared to slow-evolving droughts that happen over several years, flash droughts usually occur within weeks or months.
They’re typically caused by low rainfall, abnormally high temperatures and winds, and solar radiation – and as global temperatures rise, they’re becoming more and more common.
Rising temperatures are leading to increased evaporation rates, causing soil to lose moisture more quickly. Add to these prolonged dry periods, and you have the perfect recipe for a flash drought, which can lead to a healthy ecosystem withering away in weeks.
A recent study published in Advances in Atmospheric Sciences projects that they are likely to happen much more frequently over the next 30 to 50 years, and they could even double in parts of Europe, South America and Africa during this period.
In fact, flash droughts are already happening much more frequently today than they were in the 1950s, according to another study, published in Science.
This is mainly due to human-caused climate change, the researchers say, and the phenomenon will expand to affect more areas of the planet if greenhouse gas emissions continue to rise.
Flash droughts can cause extensive damage to agriculture, economies and ecosystems if they are not predicted and discovered early. They can also affect electricity production, public health, wildlife, political stability and public safety.
By leaving vegetation extremely dry, flash droughts can amplify the risk of large wildfires. They also lead to changes in soil moisture that can cause extensive damage to agriculture, exacerbating the current global food crisis.
Meanwhile, as the world population is expected to increase by 2 billion in the next 30 years, croplands will need to expand to meet growing demand for food. This means more and more forests are likely to be destroyed to make way for agriculture – which will further increase the risk of drought.
In a study published in Communications Earth & Environment, researchers predict that flash droughts will increasingly affect croplands on every continent by the end of the century. In Europe, the area of croplands affected could increase by up to 53 percent in a worst-case scenario, followed by South America at 50 percent, North America at 49 percent and Africa at 47 percent.
“Of all weather and climate extremes, drought will likely bring the most complex challenges to food systems and agricultural productivity over the next century,” the authors wrote.
Flash droughts present a unique challenge as they can develop so quickly. Researchers say mitigation strategies can be challenging to implement during a flash drought because they events often happen with little warning.
According to scientists at the U.S. National Integrated Drought Information System (NIDIS), it’s crucial to explore new methods to predict flash droughts and develop early warning information systems that inform response, planning and policy. They say practitioners need to be engaged in the process to better prepare for flash droughts and mitigate their impacts.
One way to help agriculture adapt to the rising risk is to improve forecasts for rainfall and temperature. This information can help farmers decide when or when not to plant. Forests can also play an essential role in preventing flash droughts by influencing rainfall patterns and releasing water during dry periods.
Experts agree that more awareness of this phenomenon is needed. Flash droughts can still occur even when no preceding signs are detected, but we can still minimize their impacts by learning more about the conditions that cause them, as well as developing better forecasts and monitoring tools to prepare for them.
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