Extreme wet and dry events becoming more frequent over the past 20 years

A new global study led by NASA confirms that over the past 20 years there has been an increased frequency of major droughts and periods of excessive precipitation and water storage on land. These changes were also found to be closely linked to global warming.

The researchers looked at 20 years of data from NASA/German GRACE and GRACE-FO satellites to identify extreme wet and dry events across the world. They found that the frequency of extreme wet and dry events increased from an average of three events per year between 2002 and 2014 to four per year from 2015-2021.

Global warming due to climate change leads to an increase in evaporation during dry events but also increases precipitation during wet events, as warmer air is able to hold more moisture.

The research team also found that the global total intensity of extreme events increased from 2002 to 2021, which is directly in line with the global warming trend.

“Global warming is going to cause more intense droughts and wet periods, which affects people, the economy, and agriculture around the world. Monitoring hydrological extremes is important for preparing for future events, mitigating their impacts, and adapting," said Matt Rodell, study co-author and a hydrologist at NASA's Goddard Space Flight Center.