The frequency of “flash droughts” is on the rise due to human-induced climate change, and the trend is expected to escalate in a warmer future, according to new research published on April 13, 2023, in the journal Science.
The study indicates that flash droughts are quickly becoming the new standard for droughts, complicating forecasting and preparation efforts.
Flash droughts are characterized by their rapid onset and development, with the potential to transform into severe droughts within a matter of weeks. These droughts are triggered by a combination of low precipitation and high evapotranspiration, causing the soil to rapidly lose its moisture content. Although they develop quickly, flash droughts can persist for months, inflicting significant damage on vegetation and ecosystems while also sparking heatwaves and wildfires.
An international team of researchers sought to determine whether there has been a shift from traditional “slow” droughts to flash droughts and to project how this trend might evolve under various carbon emission scenarios.
Study co-author Professor Justin Sheffield of the University of Southampton stated that climate change has effectively sped up the onset of droughts. “While it varies between different regions, there has been a global shift towards more frequent flash droughts during the past 64 years.”
The researchers found that the transition to flash droughts was most pronounced in East and North Asia, Europe, the Sahara, and the west coast of South America. In contrast, some regions like eastern North America, Southeast Asia, and North Australia experienced a decrease in both flash and slow droughts. However, the speed of drought onset in these areas still increased.
Interestingly, there was no evidence of a transition to flash droughts in the Amazon and West Africa. Instead, the Amazon witnessed an uptick in slow droughts, while West Africa saw an increase in the frequency and severity of both fast and slow droughts.
Professor Sheffield explained the future implications of this trend, saying, “As we head towards a warmer future, flash droughts are becoming the new normal. Our models show that higher-emission scenarios would lead to a greater risk of flash droughts with quicker onset, which pose a major challenge for climate adaptation.”
The transition to flash droughts could have irreversible consequences for ecosystems, as they may not have sufficient time to adapt to sudden water scarcity and extreme heat. Forecasting these flash droughts also poses a challenge, as current methods for predicting droughts typically rely on longer time scales.
To better prepare for and manage the increasing prevalence of flash droughts, the researchers argue that new approaches for early warnings are necessary. Additionally, there is a need to better understand the impacts of flash droughts on both natural ecosystems and human populations.
Climate change, driven primarily by the increase in greenhouse gas emissions from human activities, is impacting various weather phenomena in multiple ways. Some of these impacts include:
These are just a few examples of how climate change is impacting weather phenomena. The interactions between climate change and weather are complex, and scientists continue to study and monitor these effects to better understand and predict future changes.