Interesting video about rapid intensification of cyclones – a phenomenon that is occurring more frequently and is driven by climate change. 90% of the current heating of the earth is being absorbed by the oceans, and this heat is being held in the top 2,000 metres, not the deeper ocean. Cyclones need warmer water to intensify and normally have to travel far to get enough warm water energy. But if the ocean is warm enough, a cyclone can travel shorter distances to get the energy it needs. Rapid intensification of cyclones makes them stronger, increases the unpredictability of their path and means that they don’t dissipate as fast once they make landfall. The Arabian Sea (which lies to the west of India) has seen a particularly rapid rise in cyclone activity in the last few years, and the Indian Ocean is currently warming faster than other oceans – a 1.3 OC rise compared to 0.7 OC for all oceans. Cyclones require a minimum sea-surface temperature of 27 OC to form. Cyclone Amphan (below) which hit West Bengal in India and Bangladesh in May 2020, intensified from wind speeds of 140 km/h to 270 km/h (a super cyclone) in just 18 hours, formed in sea-surface temperatures of 34 OC, which is why it was thought to be so strong.

Cyclones in the Indian subcontinent – India – ech2o newsletter snippet