What is Sea Surface Temperature Rise? How Does It Affect the Formation of Tropical Cyclones?

The Earth’s climate system is governed by a complex interplay of land, ocean, and atmospheric processes. Among these, Sea Surface Temperature (SST) plays a crucial role, especially in regulating weather patterns, ocean currents, and the formation of tropical cyclones. In recent decades, the phenomenon of sea surface temperature rise has garnered significant attention due to its link with climate change, global warming, and increased frequency of extreme weather events.

This comprehensive article delves into:

• What is sea surface temperature rise?
• The causes of SST rise
• Its impacts on tropical cyclone formation
• The broader climatic and ecological consequences
• India-specific concerns
• The way forward for policymakers and UPSC aspirants

 

Sea Surface Temperature Rise

What is Sea Surface Temperature (SST)?

Sea Surface Temperature refers to the temperature of the upper layer of the ocean, typically the top 1-2 meters. It is measured using:

• Satellite remote sensing
• Buoys and floats
• Ships and oceanographic stations

SST is a critical parameter because:

• It influences the exchange of heat, moisture, and momentum between the ocean and atmosphere.
• It affects weather systems, including monsoons and tropical cyclones.
• It plays a role in global climate patterns like El Niño and La Niña.

 

What is Sea Surface Temperature Rise?

Sea Surface Temperature Rise is the long-term warming of ocean surfaces due to natural and anthropogenic factors, particularly global warming. According to the Intergovernmental Panel on Climate Change (IPCC), the oceans have absorbed about 90% of the excess heat generated by greenhouse gas emissions since the 1970s.

Key Statistics

• The global average SST has risen by approximately 0.13°C per decade since 1901.
• 2023 and 2024 witnessed some of the highest recorded SSTs globally.
• The Indian Ocean is warming at a faster rate than the global average.

 

Causes of Sea Surface Temperature Rise

1️⃣ Greenhouse Gas Emissions

• CO₂, CH₄, N₂O, and other greenhouse gases trap heat in the atmosphere.
• The oceans absorb most of this excess heat, causing SST to rise.

2️⃣ Global Warming

• Global atmospheric warming directly raises ocean temperatures.
• IPCC’s Sixth Assessment Report predicts continuous SST rise with ongoing emissions.

3️⃣ Natural Variability

• Phenomena like El Niño-Southern Oscillation (ENSO) cause short-term fluctuations in SST.
• Volcanic eruptions and solar activity also contribute to variations.

4️⃣ Ocean Currents and Heat Distribution

• Changes in oceanic circulation, like weakening of the Atlantic Meridional Overturning Circulation (AMOC), alter regional SST patterns.

5️⃣ Land Use Changes and Urban Heat

• Coastal development, deforestation, and urban heat islands indirectly affect SST, particularly in coastal regions.

 

Tropical Cyclones: A Brief Overview

Tropical cyclones, also known as hurricanes, typhoons, or cyclones, are intense low-pressure systems that form over warm ocean waters, typically in tropical and subtropical regions.

Key Conditions for Formation:

• Warm SST (≥26.5°C)
• Low vertical wind shear
• High humidity
• Pre-existing low-level disturbance
• Coriolis force for rotation (at least 5° latitude away from the equator)

 

How Does Sea Surface Temperature Rise Affect Tropical Cyclone Formation?

1️⃣ Increased Heat Energy

• Warmer oceans = More latent heat.
• This heat serves as the primary energy source for tropical cyclones.
• Higher SST allows cyclones to intensify rapidly and sustain high wind speeds.

2️⃣ Extended Cyclone Seasons

• Warmer SST extends the window for cyclone formation beyond the traditional seasons.
• Regions like the Arabian Sea have seen more pre-monsoon and post-monsoon cyclones.

3️⃣ Rapid Intensification

• SST rise contributes to rapid intensification (RI), where wind speeds increase dramatically in a short period.
• Recent cyclones like Amphan (2020) and Tauktae (2021) demonstrated this behavior.

4️⃣ Increased Frequency of Severe Cyclones

• Studies suggest that while the total number of tropical cyclones may not drastically increase, the proportion of Category 4 and 5 storms is rising.

5️⃣ Changes in Cyclone Tracks

• Warmer SSTs can influence the trajectory of cyclones, leading to:
• Landfalls in previously unaffected areas.
• Increased threat to heavily populated coastlines.

6️⃣ Higher Rainfall and Flooding

• Warmer air holds more moisture, leading to extreme rainfall events associated with tropical cyclones.
• This increases the risk of flash floods and landslides.

7️⃣ Slower Moving Cyclones

• Rising SST may also contribute to slower moving cyclones, leading to prolonged rainfall and extended damage, as seen in Cyclone Harvey (USA, 2017).

 

Scientific Evidence Linking SST Rise and Cyclones

• IPCC Reports: Consistently highlight the strong correlation between warming oceans and intense tropical cyclones.
• WMO (World Meteorological Organization): Confirms that climate change is amplifying the destructive power of tropical cyclones.
• Indian Meteorological Department (IMD): Notes an increase in severe cyclonic activity over the Arabian Sea.

 

India-Specific Implications

1️⃣ Increased Cyclonic Activity in Arabian Sea

• Traditionally less active, the Arabian Sea is now witnessing more severe cyclones due to faster SST rise.

2️⃣ Greater Economic Losses

• Coastal infrastructure, ports, and fisheries face mounting risks.
• The 2021 Cyclone Tauktae caused damages exceeding $2 billion.

3️⃣ Impact on Coastal Communities

• Coastal erosion, saltwater intrusion, displacement of communities, and loss of livelihoods are increasing.
• Vulnerable states include Odisha, West Bengal, Andhra Pradesh, Tamil Nadu, Kerala, Maharashtra, and Gujarat.

4️⃣ Threat to Food Security

• Cyclones damage crops, fisheries, and freshwater sources, affecting India’s food security.

5️⃣ Increased Disaster Management Burden

• Frequent cyclones strain disaster response agencies like NDMA, NDRF, and SDRF.

 

Ecological and Environmental Consequences

1️⃣ Coral Bleaching

• Rising SST leads to mass bleaching events, threatening marine biodiversity.

2️⃣ Marine Heatwaves

• Extended periods of abnormally high SST affect fisheries, disrupt ecosystems, and reduce ocean productivity.

3️⃣ Ocean Acidification

• Warmer oceans absorb more CO₂, leading to acidification that harms shell-forming species and food chains.

4️⃣ Disruption of Ocean Currents

• Changes in thermohaline circulation can alter global climate patterns, impacting monsoons and rainfall.

 

Global Examples of SST Rise Impact

• Hurricane Katrina (2005): Intensified due to high SST in the Gulf of Mexico.
• Hurricane Harvey (2017): Produced record-breaking rainfall due to slow movement and warm Gulf waters.
• Super Typhoon Haiyan (2013): One of the strongest ever recorded, linked to exceptionally warm Pacific SST.

 

Climate Change and International Response

1️⃣ Paris Agreement (2015)

• Aims to limit global temperature rise to well below 2°C.
• Success depends on significant reduction in greenhouse gas emissions.

2️⃣ IPCC Sixth Assessment Report (2021)

• Warns of irreversible impacts if SST rise continues unchecked.

3️⃣ Sendai Framework for Disaster Risk Reduction (2015-2030)

• Advocates for international cooperation on disaster preparedness and resilience-building.

 

Way Forward: Mitigation and Adaptation

✅ Reduce Greenhouse Gas Emissions

• Transition to renewable energy.
• Promote afforestation and sustainable development.

✅ Strengthen Early Warning Systems

• Improve forecasting technology for better prediction of cyclone intensity and landfall.

✅ Enhance Coastal Defenses

• Construct cyclone shelters, sea walls, and resilient infrastructure.
• Enforce strict zoning laws to prevent coastal overdevelopment.

✅ Community Preparedness

• Educate vulnerable communities.
• Conduct regular evacuation drills and awareness programs.

✅ Research and Monitoring

• Strengthen partnerships like INCOIS, IMD, and international climate monitoring agencies.
• Invest in long-term oceanographic research.

✅ International Cooperation

• India’s leadership through initiatives like ISA (International Solar Alliance) and CDRI (Coalition for Disaster Resilient Infrastructure) is crucial.

 

Conclusion

The rise in sea surface temperature is a visible symptom of the broader climate crisis facing humanity. While SST rise may seem like a distant oceanic phenomenon, its impact on tropical cyclone formation is direct and severe, especially for vulnerable countries like India. As extreme weather events become more frequent and intense, integrating climate science into national disaster planning, development policies, and international climate negotiations becomes critical.

For UPSC aspirants, understanding the interconnectedness of climate change, oceanography, disaster management, and policy responses is essential not only for the exam but also for comprehending one of the gravest challenges of our times.

 

UPSC Prelims & Mains Pointers

Topic	Key Points
Sea Surface Temperature	Rising due to global warming; critical for cyclone formation
Cyclone Formation	Requires SST ≥26.5°C, low wind shear, moisture
SST Rise Impacts	Rapid intensification, prolonged cyclone seasons, extreme rainfall
India Specific	Arabian Sea activity, coastal damage, disaster management
Solutions	Emission control, forecasting, coastal infrastructure, community training

 

 

Frequently Asked Questions

Q1: What is sea surface temperature rise?
Sea surface temperature rise refers to the increase in the temperature of the ocean’s upper layers due to global warming and climate change.

Q2: How does sea surface temperature affect tropical cyclones?
Warmer sea surfaces provide more heat energy, fueling stronger and more frequent tropical cyclones, causing rapid intensification and greater rainfall.

Q3: Why is sea surface temperature rising?
The primary causes are greenhouse gas emissions, global warming, oceanic circulation changes, and natural climatic variability.

Q4: Which Indian agency monitors SST?
The Indian National Centre for Ocean Information Services (INCOIS) and the Indian Meteorological Department (IMD) monitor SST.

Q5: How can we mitigate SST rise impacts?
By reducing emissions, strengthening disaster preparedness, improving forecasting, and investing in resilient infrastructure.