Typhoons: the hidden lifeline in a drying world

Pohang University of Science & Technology (POSTECH)

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Change in Extreme Long Duration Drought Frequency by landfalling Tropical Cyclones

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Credit: POSTECH

A research team led by Professor Jonghun Kam from POSTECH (Pohang University of Science and Technology) has revealed that typhoons are a critical factor in mitigating global droughts by simulating a scenario where typhoon-induced precipitation is removed. The study delivers the message that "imagining a world without typhoons is the starting point for understanding future droughts," and was recently published in Geophysical Research Letters, a leading international journal in the field of Earth sciences.

 

The Two Faces of Typhoons

Typhoons are commonly perceived as disasters that bring floods and destruction. However, the rain they leave behind plays a vital role in delaying droughts and maintaining the water cycle. Despite this, the impact of a lack of typhoons on drought has rarely been systematically analyzed. This study began with a simple but profound question: "How much would drought patterns change if typhoons never occurred?"

 

Simulating a "World Without Typhoons"

Using global data spanning 40 years (1980–2020), the research team conducted global hydrological model experiments comparing scenarios with and without typhoon precipitation. Essentially, they placed a "world with typhoons" and a "world without typhoons" side-by-side to analyze differences in soil moisture, river runoff, and drought intensity.

The results showed that if typhoon precipitation was removed, soil moisture declined sharply across many regions worldwide, leading to significantly more severe drought conditions. Notably, the way typhoons moistened the soil and the duration of that effect varied significantly by region:

• Arid and semi-Arid Regions (e.g., Oceania): Soil moisture provided by typhoons vanished within a year, and the absence of typhoons resulted in extreme drought.
• Humid Regions (e.g., East Asia): Soil moisture did not deplete entirely even without typhoon rain.

These findings indicate that while a lack of typhoons is a decisive trigger for drought in some regions, it acts as a condition that exacerbates drought in others.

 

Implications for Water Management

This research introduces a new variable for water management in the era of climate change. As typhoon paths and frequencies shift, some regions may face droughts far more severe than anticipated. These impacts may extend beyond agricultural production to include water resource management, urban water supply, and disaster response strategies.

 

Professor Jonghun Kam highlighted the significance of the study, stating:

"While landfalling typhoons have primarily been a research interest as the key cause of flooding and damage, this study scientifically shifts the perspective toward its role in alleviating droughts. The findings of this study highlight the need for climate models that can accurately simulate both typhoons and droughts simultaneously."

This research was supported by the National Research Foundation of Korea (NRF) through the Individual Basic Research Program.

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Journal

Geophysical Research Letters

DOI

10.1029/2025GL120290 

Article Title

Tropical Cyclones Unevenly Shape Drought Propagation