Hydroclimate whiplash is a term used to refer to rapid weather shifts between very wet and intensely dry, and this phenomenon is increasing around the world according to a new study reported in Nature Reviews Earth & Environment.
Right now, the effects of hydroclimate whiplash are on full display in Southern California, which has experiened lengthy periods of drought, followed by deluges of water from atmospheric rivers in 2022 and 2023. Then in 2024, temperatures were at a record high and vegetation like brush and grasses grew in abundance. More recently, it began to dry out again and the region exploded in flames, destroying neighborhoods.
As the globe's average air temperature increases, the atmosphere is able to hold more water, and this 'atmospheric sponge' is expanding and intensifying, boosting hydroclimate whiplash. The atmospheric sponge will also take in and release seven percent more water every time the average temperature rises by one degree. The atmosphere can soak up water from soils, plants and shrubs too, drying them out and making them prone to burn. This recent study has suggested that it is now time for officials to turn their attention to managing cycles of both extreme rainfall and drought, rather than each on its own.
The study indicated that hydroclimate whiplash has increased from 31 to 66 percent since the middle of the 20th century, which outpaced predictions from climate models. The phenomenon will get at least twice as common if the global temperature average increases by three degrees Celsius above pre-industrial levels.
Droughts and floods are not the only processes in hydroclimate whiplash--there are also periods in between, like the cycle of blooming plants, which then burn when another drought starts. Landslides can then occur on land where fires have destroyed trees and plants.
"We can't look at just extreme rainfall or extreme droughts alone, because we have to safely manage these increasingly enormous influxes of water, while also preparing for progressively drier interludes," said senior study author Daniel Swain, a climate scientist with UCLA and UC Agriculture and Natural Resources. "That's why co-management is an important paradigm; it leads you to more holistic conclusions about which interventions and solutions are most appropriate, compared to considering drought and flood risk in isolation."
Many areas are forecast to see increases in hydroclimate whiplash, which will probably increase the most in the tropical Atlantic and Pacific, north Africa, the Middle East, South Asia, and northern Eurasia.
"Increasing hydroclimate whiplash may turn out to be one of the more universal global changes on a warming Earth," Swain said.
Sources: University of California - Los Angeles, Nature Reviews Earth & Environment