Madrid, 30 years (European Press)

The study concluded that feedback loops from Earth itself are likely contributing to this trend.

The research analyzed four decades of global meteorological and hydrological data, and found seven regional hotspots around the world where the trend was worsening: eastern North America, Europe, eastern Asia, southeast Asia, southern Australia, southern Africa, and southern South America.

“We are particularly concerned about the sudden shift from drought to floods,” co-author Zhong Liangyang, a professor at the School of Geosciences at the University of Texas at Austin, said in a statement. “Normally a community would have difficulty responding to some kind of natural disaster like a drought, but now suddenly there are floods as well. This is what is happening in many places.”

The study was published in the journal Earth and Environmental Communications.

The team examined three global sets of meteorological and hydrological data from 1980 to 2020 to document this trend. They found that the probability of a sudden shift from drought to dangerous rain increased by about 0.25 to 1% per year over that period, depending on location.

There have been several notable examples of the sudden shift from severe drought to potentially dangerous heavy rainfall in recent years. For example, in December 2022, California was facing its worst drought in a millennium, but this situation quickly changed due to heavy rains that caused record flooding in January, February and March 2023.

There are many factors that can contribute to sudden changes in climate and weather, including El Niño and La Niña weather patterns and climate change itself. But the researchers said this is the first study to look at the potential impact of processes involving the Earth itself. Researchers discovered ground feedback loops using a relatively new technique of causal analysis, a statistical technique that can help determine whether one factor is directly responsible for the occurrence of another.

During periods of severe drought in humid regions, water evaporation from soil and plants accelerates, pushing precipitation into the air and providing a source of moisture for the development of heavy rains.

During extreme droughts in arid regions, hot weather and low pressure create a pressure gradient that pulls moisture from other areas, such as the ocean.

Co-author Xu Wang, associate professor at Hong Kong Polytechnic University, said such rapid changes are expected to be more likely with climate change. He said the new research, particularly the discovery of terrestrial mechanisms, could be used to help increase the accuracy of predictive weather models, as well as help communities prepare for transitions between periods of drought and heavy rain.

“Climate change is fueling successive droughts and floods that have caused widespread destruction, causing loss of life and damage to property, infrastructure and the environment,” Wang said. “Our findings provide information for the development of early warning systems to mitigate the effects of rapid, dry transitions.” and wet.”