Day 13 – Q 4. What are the factors that have led to the increased frequency of tropical cyclones? Examine.
4. What are the factors that have led to the increased frequency of tropical cyclones? Examine.
उष्णकटिबंधीय चक्रवात की बढ़ती आवृत्ति के कारक क्या हैं? जांच करें।
Approach
- This is a simple direct question of geography. Start with a short introduction to ‘Tropical Cyclones’, and mention about increasing frequency of these cyclones.
- In body of the answer, mention various factors such as rising temperatures, changing weather conditions and such other factors are leading to increasing frequency.
- Since question asked to ‘examine’, simply enlisting the factors will not be sufficient, elaborate them and end the answer with way forward.
Introduction
- Tropical cyclones form over oceans with surface temperatures above 26°C as strong low pressure systems that can reach diameters of more than 500 km.
- Evaporation of immense amounts of water vapour under these high temperature conditions and the related condensation aloft provide ample energy for the cyclone dynamics, leading to high wind speed and extreme precipitation.
- These usual natural phenomena are occurring more frequently than usual due to various anthropogenic and changing natural factors.
Body
We had Ockhi cyclone last year and now Gaja, both of them originated in Bay of Bengal, but travelled all along till western coast of peninsular India.
Similar events of increased frequency as well as intensity are observed throughout the topical oceans.
The factors leading to increased frequency of tropical cyclones
- Increase in frequency of tropical cyclones is specifically observed in Arabian Sea. Here winter monsoon circulations, plays an important role.
- The interplay of global warming, climate variability and weather changes, the winter northeast monsoon circulation has been weakening over the years.
- One important factor is the wind shear, or the change in direction and speed of the winds from bottom to the top of the atmosphere.
- Generally, this wind shear is relatively strong in the Arabian Sea compared to the Bay of Bengal.
- Opposing winds prevent cyclones from developing vertically, this wind shear is weakening in the Arabian Sea with increased carbon dioxide in the atmosphere.
- Important contributors to rise in global temperatures, such as manmade black carbon particles and sulphate emissions might have increased the intensity of these cyclones in almost all oceans of tropics.
- On the other hand burning of fossil fuels such as petrol, diesel, etc. was the main reason for climate change as it had affected the greenhouse gas cover around the earth, leading to a rise in atmospheric temperature.
- Similarly, aerosols, greenhouse gases, volcanic activity, solar variability, and internal climate variability also add degrees to sea surface temperature, making the conducive weather conditions for tropical cyclones.
- A La Niña (a weather pattern in the Pacific Ocean that is less damaging than El Niño) event is unfolding over the Pacific. Studies have shown that La Niña conditions change the atmospheric circulation over the north Indian Ocean and make them favourable for cyclogenesis.
Way forward
- The most important factors responsible for increase in frequency of tropical cyclones are global warming and climate change.
- According to recent IPCC report, the world is already 1°C hotter than what it was 150 years ago.
- It could witness greater frequency of droughts and floods, tropical cyclones, etc. if the planet heats by a further 0.5°C. That could happen anytime between 2030 and 2050.
- The need of the hour is to implement the conventions like Paris Accord and INDCs in letter and spirit to control the rising global temperatures.
- Conserving the existing ecosystem is the best way to counter climate change.
Best Answer: Ravi Kishore Boddu
