Kolkata: Cyclone Arnab’s rapid intensification highlights growing risks to Sundarbans and coastal Bengal as unusually warm seas create favourable conditions for recurrent and powerful storms and extreme rainfall
The latest ocean temperature analysis cited in the assessment shows that global sea surface temperatures in September 2026 were 1.10°C above average, setting a record for the fourth consecutive month.
“Warmer-than-normal sea surface temperatures and potential influence of El Nino conditions may have contributed to its intensity,” said former India Meteorological Department director general KJ Ramesh. Unusually warm sea surface temperatures in the Bay of Bengal, coupled with the evolving El Nino phenomenon, could create conditions favourable for more powerful cyclones, raising fresh concerns over the vulnerability of West Bengal’s coastline. they warn that storms developing over increasingly warm waters could intensify faster, unleash heavier rainfall and leave coastal communities with less time to prepare While scientists have not established that these conditions will necessarily bring more cyclones ashore in Bengal. For Bengal, still grappling with the consequences of Amphan and Yaas, Arnab is a reminder that the warming Bay of Bengal remains a breeding ground for potentially destructive cyclones, particularly during the post-monsoon season. Meteorologists attribute the rapid strengthening of tropical cyclones partly to the increasing heat stored in ocean waters. Warmer seas provide the energy and moisture necessary for storms to intensify, while a warmer atmosphere can hold more water vapour, increasing the potential for extreme rainfall. “While global warming does not cause El Nino, the background warming adds to the extra heat and intensifies the impacts of extreme weather systems. Scientists believe such warming could have serious implications for the North Indian Ocean, where cyclones have shown an increasing tendency towards rapid intensification. For Bengal, the implications extend well beyond coastal landfall. The Sundarbans, already exposed to rising sea levels, saline intrusion and erosion, face the possibility of repeated damage to embankments, agriculture and settlements. Kolkata and its surrounding urban areas also remain vulnerable to intense rainfall, waterlogging and disruptions to essential services.