Q.What is sea surface temperature rise? How does it affect the formation of tropical cyclones?
Model Answer
View this Question In PYQ RealmSyllabus Point
- Important Geophysical Phenomena such as earthquakes, Tsunami, Volcanic activity, cyclone etc.
Approach
- Introduction (Definition) (30-40 words): Briefly define Sea Surface Temperature (SST) rise.
- Body (170-180 words): Write about how SST rise affects tropical cyclone formation (warmer waters providing more energy for cyclone development).
- Conclusion (30-40 words): Emphasize how SST rise exacerbates cyclone formation and intensity, making climate mitigation and disaster preparedness crucial for future resilience.
Introduction
Sea Surface Temperature (SST) rise refers to the warming of the ocean's uppermost layer. This phenomenon is primarily driven by global warming resulting from increased greenhouse gas emissions. According to the Intergovernmental Panel on Climate Change (IPCC), global average SST has increased by approximately 0.88°C since the late 19th century, with particularly rapid warming observed in tropical oceans, such as the Indian Ocean (which has warmed by 1.2°C since the 1950s).
graph TD MarineHeatwaves["Marine Heatwaves"] --> SST["Rising Sea Surface Temperatures"] GHG["Greenhouse Gas Emissions"] --> SST ClimateChange["Climate Change"] --> SST NaturalPhenomena["Natural Phenomena"] --> SST HeatAccumulation["Heat Content Accumulation"] --> SST ReducedAlbedo["Reduced Albedo"] --> SST DecreasedUpwelling["Decreased Upwelling"] --> SST
Body
Impact of SST Rise on Tropical Cyclones:
-
Enhanced Cyclone Formation: Tropical cyclones require a minimum sea surface temperature of 26.5°C to form. Rising SSTs expand the geographical areas and duration of the year where conditions are favorable for cyclogenesis.
- Example: The Arabian Sea, which was historically less prone to cyclones, has seen a marked increase in cyclonic activity (e.g., Cyclone Tauktae, 2021).
-
Increased Cyclone Intensity: Warmer ocean waters accelerate evaporation and increase the moisture content in the atmosphere, providing more fuel for cyclones. This leads to stronger winds, heavier rainfall, and more devastating storm surges.
- Example: Cyclone Fani (2019) underwent rapid intensification over the Bay of Bengal, causing widespread destruction in Odisha.
-
Shift in Cyclone Tracks: Rising ocean temperatures alter atmospheric circulation patterns, shifting cyclone tracks toward higher latitudes and previously cooler regions.
- Example: Cyclone Amphan (2020) impacted parts of West Bengal and Bangladesh, areas that are increasingly experiencing severe cyclonic storms.
-
Prolonged Cyclone Duration: Higher SSTs allow cyclones to sustain their energy for longer periods, enabling them to travel greater distances overland and cause prolonged damage.
- Example: Cyclone Kyarr (2019) in the Arabian Sea maintained its intensity for 10 days, affecting multiple nations.
-
Increase in Storm Surge Heights: Thermal expansion of warmer waters raises local sea levels, which significantly amplifies the height and impact of storm surges during a cyclone.
- Example: During Cyclone Nargis (2008) in Myanmar, a massive 12-foot storm surge led to catastrophic flooding.
-
Intense Rainfall Events: Elevated SSTs increase the atmospheric moisture-holding capacity, leading to extremely heavy and concentrated rainfall during cyclones.
- Example: Cyclone Tauktae (2021) triggered torrential rainfall across Gujarat, Maharashtra, and Kerala.
-
Impact on Frequency and Variability: Warming oceans make cyclonic activity highly unpredictable, altering their seasonal frequency and patterns.
- Example: El Niño events in the Pacific Ocean, driven by warmer waters, significantly influence global cyclone frequency.
-
Newly Affected Regions: SST rise is causing cyclones to emerge in regions that were previously unaffected or rarely hit by such storms.
- Example: Cyclones are increasingly impacting the Mozambique Channel in East Africa (e.g., Cyclone Idai, 2019).
-
Economic and Humanitarian Losses: The intensification of cyclones due to warmer oceans leads to catastrophic damage to infrastructure, agriculture, and human lives.
- Example: Cyclone Yaas (2021) caused economic damage exceeding ₹15,000 crores in India.
-
Warming-Induced Feedback Loops: SST rise leads to more frequent and intense cyclones, which in turn churn the ocean, mixing deeper waters and further redistributing heat, creating complex feedback loops.
Conclusion
Rising sea surface temperatures driven by climate change have significantly exacerbated the intensity, duration, and geographic spread of tropical cyclones. Recent storms like Amphan, Fani, and Tauktae underscore this growing threat. Addressing this challenge requires global commitment to climate mitigation alongside robust local adaptation strategies, including resilient coastal infrastructure and advanced disaster preparedness.