Natural shifts in sea-surface temperatures, specifically the El Niño-Southern Oscillation, act as a global brake on synchronized droughts, according to research led by the Indian Institute of Technology Gandhinagar (IITGN). The study, published in Communications Earth & Environment, found that synchronized droughts affect only 1.8% to 6.5% of Earth’s land area at once, contradicting earlier estimates that one-sixth of the planet could dry out simultaneously.
How do ocean temperatures prevent synchronized droughts?
The research team identified that shifts in sea-surface temperatures in the Pacific and other oceans restrict how far and how evenly droughts expand across the globe. By treating drought onsets as events in a global network, researchers could trace how distant regions connect or remain isolated.
Danish Mansoor Tantary, a co-author and former IITGN master’s student now pursuing a PhD at Northeastern University, explained that these ocean-driven cycles create a “patchwork of regional responses.” This patchwork prevents a single, massive drought from covering multiple continents at the same time.
The impact of El Niño and La Niña
The El Niño-Southern Oscillation (ENSO) serves as a primary driver of these shifts. During El Niño years, Australia frequently emerges as a major “drought hub.” In contrast, La Niña years tend to spread droughts out geographically rather than concentrating them into a single global pattern.
Earlier climate claims suggested that as much as one-sixth of the Earth could experience drought at the same time. This new study of records from 1901–2020 shows the actual synchronized area is likely much smaller, between 1.8% and 6.5%.
What are the primary drivers of drought severity?
While rainfall remains the dominant factor in drought, the influence of rising temperatures is increasing in specific parts of the world. The study analyzed how precipitation and temperature interact to determine how severe a drought becomes.
According to the researchers, roughly two-thirds of long-term changes in drought severity are linked to changes in precipitation. The remaining one-third is attributed to rising evaporative demand caused by warming temperatures. Dr. Rohini Kumar, a senior scientist from the Helmholtz Centre for Environmental Research, noted that while rainfall is the main driver in Australia and South America, the influence of temperature is growing in mid-latitude regions like Europe and Asia.
Which regions are most vulnerable to crop failure?
The research identified several “drought hubs” where regional weather patterns frequently lead to dry periods. These include Australia, South America, southern Africa, and parts of North America. When these hubs experience drought, the impact on food production can be significant.
Hemant Poonia, an AI Scientist at IITGN, reported that in many major agricultural regions, the probability of crop failure rises sharply during moderate droughts. Specifically, the risk often climbs above 25%, and for certain staples like maize and soybean, the failure rate can exceed 40% to 50%.
| Crop Type | Potential Failure Risk |
|---|---|
| General Crops | Above 25% |
| Maize & Soybean | 40%–50%+ |
How can global food supplies be protected?
Because droughts do not hit all regions simultaneously, the study suggests that global food security can be managed through strategic planning. Instead of viewing weather events in isolation, the team advocates for viewing Earth as an interconnected system.
Prof Vimal Mishra, a water and climate expert at IITGN, stated that these findings highlight the necessity of international trade, storage, and flexible policies. By using the natural diversity of drought timing, countries can use smart planning to buffer global food supplies.
Dr. Udit Bhatia, the lead author and principal investigator of the Machine Intelligence and Resilience Lab and the AI Resilience and Command (ARC) Centre at IITGN, suggested that policymakers can use this data to focus resources on specific drought hubs. This approach aims to stabilize global markets before local crop failures trigger international price spikes.
Focus on “early warning” regions within identified drought hubs to create supply chain pipelines that can stabilize markets before local shortages become global crises.
Frequently Asked Questions
What is a “drought hub”?
A drought hub is a specific geographic region, such as Australia or South America, that frequently experiences drought onsets that can connect to other distant regions in a global network.
Why is the ocean temperature important for drought?
Ocean temperature shifts, like the El Niño-Southern Oscillation, change rainfall patterns globally. These shifts create a “patchwork” of weather that prevents droughts from happening everywhere at once.
Is temperature making droughts worse?
Yes. While rainfall is the main driver, roughly one-third of drought severity changes are now linked to rising evaporative demand caused by increasing temperatures, particularly in Europe and Asia.
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