Recent studies confirm a concerning trend: tropical cyclones in coastal regions around the globe are intensifying at a faster rate, with climate change playing a significant role in this escalation.
Understanding the Rising Threat
Tropical cyclones, known regionally as hurricanes or typhoons, are formidable low-pressure systems that develop in tropical zones between the latitudes of 20ºS and 20ºN. These systems, which are not linked to cold fronts, thrive in high temperature and humidity conditions and are capable of causing extensive destruction, second only to earthquakes in terms of natural disaster severity. A study published in the journal Earth’s Future highlights a notable increase in the rate of these cyclones' intensification over recent years, especially near coastal areas.
Acceleration in Cyclone Intensity
The research examined how tropical cyclones have been intensifying more rapidly near coastal regions, correlating this trend with global climate change. Between 1979 and 2000, the average intensification rate was about 0.69 km/h every six hours. This rate increased to 2.13 km/h every six hours from 2000 to 2020. Furthermore, over a 24-hour period, the global average increase was about 5.56 km/h near coastal regions.
Key Factors Behind the Intensification
The study indicates that increased relative humidity and a weakening in the vertical wind shear are the primary drivers behind the faster intensification of tropical cyclones. Warmer climates tend to weaken the vertical wind shear—a rapid change in wind speed and direction at different altitudes—particularly near coastal areas in the northern hemisphere. As the ocean surface warms, it alters atmospheric circulation patterns, resulting in weaker wind shear. Additionally, a warmer atmosphere can hold more water vapor, creating conditions ripe for cyclone formation and intensification.
Implications for Coastal Regions
This intensification of cyclones poses significant socio-economic threats and operational challenges, particularly for coastal communities. The study underscores the importance of understanding these changes for weather forecasters and policymakers to better prepare and respond to the increasing risks.
The findings from the study serve as a critical reminder of the ongoing impact of climate change on natural disaster patterns and the urgent need for global attention to mitigate these effects. The continuity of such trends could have profound implications for coastal safety and disaster management strategies worldwide.
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2023EF004230