Why rainfall is becoming much less predictable – and what it means for the planet

A study looking at data from the last century has found weather patterns have become more variable as global warming has increased

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Rain patterns have been getting more unpredictable over the last century as the planet has warmed. Photo: AP

Published: 6:01pm, 2 Aug 2024

Human-induced global warming has increased precipitation variability across 75 per cent of the world’s land area, leading to more unpredictable rain patterns, new research has shown.

And this could have worldwide consequences, affecting agriculture, water supply and the global economy.

Studying data from 1900 to 2020, scientists found that the increased variability had been particularly pronounced in Europe, Australia and eastern North America.

Researchers from the Institute of Atmospheric Physics at the Chinese Academy of Sciences (CAS) and the Met Office Hadley Centre in Britain detailed their findings in peer-reviewed journal, Science, on July 25.

“As the climate warms, the consequent moistening of the atmosphere increases extreme precipitation,” the researchers wrote. “Precipitation variability should also increase, producing larger wet-dry swings, but that is yet to be confirmed observationally.”

Precipitation variability refers to irregular and non-uniform precipitation patterns, including rainfall and snow, over short or long-term timescales. It is important because as the variability increases, the extreme wet and dry swings can lead to flooding and droughts.