Question.
- What are Marine Heatwaves?
- What is the role of marine heatwaves in shaping the intensity and destructiveness of tropical cyclones?
- Analyse their impact on coastal ecosystems.
- Suggest measures for climate-resilient coastal planning.
(Syllabus: General Studies – 1, World Geography, Geographical Phenomena)
Answer.
Marine Heatwaves (MHWs) are periods of abnormally high sea surface temperatures compared to normal conditions, lasting for at least 5 days.
They have become more frequent due to climate change, with their frequency doubling since 1982.
Role of Marine Heatwaves in Intensifying Tropical Cyclones:
Tropical cyclones depend on warm ocean water (above ~27°C) for energy.
For example,
Arabian Sea cyclones (e.g., Cyclone Tauktae, 2021) became stronger due to unusually warm waters. Increasing marine heatwaves in the Arabian Sea are linked with extreme rainfall events in India.
Marine heatwaves increase this energy supply in the following ways:
1. Rapid Intensification
Extra-warm water provides more latent heat energy; as a result, it leads to a sudden increase in wind speed and strength.
As per a recent study (2026):
- Cyclones over marine heatwaves cause ~60% more billion-dollar disasters
2. Stronger Winds and Rainfall
Higher sea temperatures → more evaporation → more moisture; resulting in:
- Heavier rainfall
- Stronger winds
which increases damage significantly in the coastal economy and ecosystem.
3. Longer Duration of Cyclones
Warm waters sustain cyclones for a longer time, and it slowly weakens even after landfall by supplying the continuous energy from the marine heatwave.
Impact of Marine Heatwave on Coastal Ecosystems:
- Marine heatwaves affect ecosystems supporting over 3 billion people globally.
- Marine heatwaves severely disturb coastal ecosystems; the following are the impacts:
1. Coral Bleaching
- High temperatures damage coral reefs
- Example: Great Barrier Reef bleaching events
2. Loss of Marine Biodiversity
- Mass death of fish and marine organisms
- Example: Large fish deaths observed off Australia due to heatwaves
3. Harmful Algal Blooms
- Warmer water increases toxic algae growth, which affects fisheries and human health.
4. Economic Losses
- Cyclone's destruction of coastal infrastructure
- Fisheries collapse
- Coastal tourism decline
- Loss of livelihoods in coastal regions
Need for Climate-Resilient Coastal Planning:
The following are some measures for climate-resilient coastal planning:
1. Early Warning Systems
Improve forecasting of marine heatwaves and cyclones
2. Ecosystem-Based Adaptation
- Protect mangroves, coral reefs (natural barriers)
- Restore coastal ecosystems
3. Climate-Resilient Infrastructure
- Cyclone-resistant housing
- Coastal zoning regulations
4. Global Climate Action
- Reduce greenhouse gas emissions
- Limit ocean warming
Marine heatwaves are emerging as a critical driver of extreme climate events, especially tropical cyclones. They not only increase disaster intensity but also threaten coastal ecosystems and livelihoods.
Going forward, integrating scientific forecasting, ecosystem protection, and resilient infrastructure planning is essential to building climate-resilient coastal systems and ensuring sustainable development.
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