Q. Discuss the factors influencing the formation and intensity of tropical cyclones. How has climate change affected the frequency and severity of these weather phenomena in the Indian subcontinent? [15 Marks] [250 Words]

Approach:

• Introduction:

• • • Definition of tropical cyclones
    • Brief mention of their significance in the Indian subcontinent

• Body:

• • • Factors influencing tropical cyclone formation and intensity
    • Climate change impacts on cyclones globally
    • Specific effects on cyclones in the Indian subcontinent
    • Examples of recent severe cyclones in the region
    • Future projections and implications

• Conclusion:

• • Summary of key points
  • Importance of understanding these changes for disaster preparedness

Model Answer:

Introduction: Tropical cyclones, also known as hurricanes or typhoons, are intense low-pressure systems that form over warm tropical oceans. These powerful storms significantly impact the Indian subcontinent, affecting millions of lives and causing substantial economic damage annually.

Body:

Factors Influencing Tropical Cyclone Formation and Intensity: 

• Warm ocean surfaceIncreased temperatures above 26.5°C provide essential heat energy for cyclone development. The Bay of Bengal exemplifies this with its frequent cyclone formation.
• Atmospheric instability, caused by temperature differences between the ocean surface and upper atmosphere, drives convection and cyclone intensity. India's pre-monsoon and post-monsoon periods often have suitable conditions.
• High humidity in the lower and middle troposphere supplies moisture for cloud formation and latent heat release, powering the cyclone. Monsoon seasons in India create favorable humidity conditions.
• The Coriolis force causes cyclonic rotation, explaining why cyclones rarely form within 5° of the equator. This is evident in the northern Bay of Bengal's cyclone patterns.
• Low vertical wind shear allows for vertical storm stacking and intensification. El Niño years often have higher shear, reducing cyclone activity in the Indian Ocean.
• Pre-existing low-level disturbances, like easterly waves or monsoon depressions, often serve as "seeds" for cyclone development.

Climate Change Impacts on Tropical Cyclones Globally: 

• Rising sea surface temperatures increase cyclone energy, potentially leading to stronger, more frequent storms. Global sea temperatures have risen 0.13°C per decade since 1900.
• Sea level rise (8-9 inches since 1880) worsens storm surge impacts, increasing coastal flooding and erosion during cyclones.
• Changing atmospheric patterns may alter cyclone tracks and landfall locations, shifting the distribution of cyclone impacts globally.

Effects on Cyclones in the Indian Subcontinent: 

• Increased intensity: More rapid intensification and higher wind speeds observed, exemplified by Cyclone Amphan's super cyclonic status in 2020.
• Higher precipitation: Warmer atmosphere holds more moisture, leading to heavier rainfall and increased flooding risk, as seen with Cyclone Tauktae in 2021.
• Shifting seasons: Potential changes in cyclone formation timing, affecting disaster preparedness and agriculture. Recent years show an increase in post-monsoon Arabian Sea cyclones.
• Changing distribution: Possible shifts in cyclone tracks and landfall locations, with some areas experiencing more frequent cyclones, such as the increase in Arabian Sea cyclones affecting western India.

Conclusion: Climate change is significantly influencing tropical cyclone patterns in the Indian subcontinent, with trends towards more intense storms and shifting geographical distributions. Understanding these changes is crucial for improving early warning systems, enhancing disaster preparedness, and developing climate-resilient infrastructure to protect vulnerable coastal communities.