Increasing Frequency of Multi-Year Droughts Worldwide

January 25, 2025

Multi-year droughts (MYDs) are increasingly common and severe, as brought into light by a recent 40-year study. The research indicates that these droughts have expanded globally, impacting ecosystems and water supplies. This trend is linked to climate change, which exacerbates drought conditions. The study, conducted by a consortium of researchers from various institutions, analysed data from 1980 to 2018.

About Multi-Year Droughts

Multi-year droughts are prolonged dry periods lasting two years or more.
These events lead to soil moisture depletion. They also result in reduced streamflow, which can have severe consequences for agriculture and ecosystems. MYDs can cause massive crop failures and increased tree mortality.
The study identified 13,176 MYDs from 1980 to 2018, each representing an event of duration.

Global Impact of Droughts

The research showed that the global land area affected by MYDs has increased by approximately 50,000 square kilometres annually. The most affected regions include temperate grasslands. The study identified the ten most severe MYDs across various continents, with notable occurrences in central Chile, the western United States, and parts of Australia.

Notable Drought Events

Among the top ten MYDs, five occurred between 2007 and 2018. The eastern Congo basin experienced the longest MYD, lasting from 2010 to 2018 and affecting an area of over 1.4 million square kilometres. The southwestern Amazon also faced a nine-year MYD, with its peak impact occurring in 2015. These events illustrate the extensive reach and duration of MYDs globally.

Influence of El Niño Events

The study found a correlation between MYD occurrences and El Niño events in 1998, 2010, and 2015. This suggests that the effects of El Niño extend beyond the tropics, influencing drought patterns in various regions. The years following these El Niño events saw some of the largest areas impacted by MYDs.

Future Projections and Preparedness

The study warns that long-lasting droughts may become more frequent and severe in the 21st century. It emphasises the need for better preparedness and collaborative efforts to mitigate the impacts of these extreme events. Effective strategies are crucial for adaptation to the changing climate and its associated challenges.

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