Climate change behind Arabian Sea cyclones
Scientists and meteorologists have attributed the increasing number of cyclones, including the latest one (Tauktae), to climate change. More so, because of the intensity with which they have now started hitting the Arabian Sea.
According to a paper by Climate Trends, a Delhi-based strategic agency that works towards building awareness around climate change and low carbon development, cyclones are fuelled by available heat in the water bodies and the conducive temperature for the intensification of the cyclone is 28°C and above.
The Bay of Bengal is usually warmer than the Arabian Sea and, therefore, hosts more tropical storms.
However, the scenario is now changing, said the paper, with sea surface temperatures (SSTS) increasing rapidly in the last century. As a result, SSTS in the Arabian Sea are over the threshold values, which leads to active convection, torrential rainfall and intense cyclones.
Recent cyclones such as Ockhi, Fani, and Amphan have confirmed the trend, intensifying from a weak cyclonic storm to an extremely severe cyclone in less than 24 hours due to exceptionally warm SSTS, the paper said.
This will be the fourth consecutive year of a pre-monsoon cyclone over the Arabian Sea, said Roxy Mathew Koll, scientist, Indian Institute of Tropical Meteorology. This is also the third consecutive year when a cyclone has come very close to the west coast of India, added Koll, who is the lead author of the chapter “Abrupt Changes and Managing Risks” in a report on ocean and cryosphere by the Intergovernmental Panel on Climate Change (IPCC).
“Sea surface temperatures in the Arabian Sea have increased rapidly during the past century and this has led to an increase in the frequency and intensity of cyclones here,” he said. Climate projections indicate that the Arabian Sea will continue to get warmer due to increasing carbon emissions, resulting in more intense cyclones in the future, he added.
“Considering that both cyclones and floods due to heavy rains are increasing across the west coast along with a gradual rise in sea level, we need to be prepared,” Koll said.