Climate change is causing more frequent, intense cyclones on India’s western coast
Changes in the patterns of ocean and atmosphere warming are causing more frequent and severe tropical cyclones in the Eastern Arabian Sea, next to India’s west coast, according to a new study.
Typically, tropical cyclones usually happen in the Arabian Sea at the start of the southwestern monsoon between March and June, as well as after the season, between October and December.
“In 2019, the Arabian Sea witnessed five cyclones as compared to its normal count of three, and the year 2019 corresponds to a positive IOD (Indian Ocean dipole) phase. Hence, under favourable natural climate modes, warming of Arabian Sea can increase the frequency and intensity of tropical cyclones in the North Indian Ocean,” said S Abhilash, co-author of the study published in Scientific Reports, to indianexpress.com. He is an associate professor in the Department of Atmospheric Science at the Cochin University of Science and Technology.
The Indian Ocean Dipole and its effect on cyclones
The IOD is similar to the El Nino, where one part of the ocean gets warmer than the other. During its positive phase, sea surface temperatures get warmer, and there is more precipitation (rain) in the western Indian Ocean region. This corresponds to more rain in the eastern Indian Ocean.
“The recent increasing frequency of extremely severe cyclonic storms over the ARB during the post-monsoon season is due to anthropogenic influence rather than natural variability,” explained Abhilash, emphasising that human-caused climate change is responsible for the intensification and increase in the frequency of cyclones.
Cyclones could affect the entire western coast of India from Gujarat to Thiruvananthapuram
As the eastern Arabian Sea changes, the coastlines of western India are increasingly at risk. As the intensity of cyclones increase, so does their potential to cause high wind, storm surges, severe rainfall, and more. This means that cyclones could pose more and more of a threat to all densely populated coastal regions along the western coast, from Thiruvananthapuram to the coast of Gujarat.
“This is something we have never seen before in the Arabian Sea. We need more studies about these trends. This is especially going to affect the lives and livelihood of the indigenous coastal communities and artisanal fishers,” added Abhilash.
According to co-author Mrutyunjay Mohapatra, this report calls for changes to development strategies to account for the dangers posed by more intense and frequent cyclones. There is also a need to develop new policy and technology initiatives in the areas of storm warning, impact-based local weather services and reliable localised weather services. Mohapatra is the Director General of Meteorology at the Indian Meteorological Department (IMD).
‘Forecasting with Fishers’
This research is part of the Forecasting with Fishers project that the Advanced Centre for Atmospheric Radar Research (ACARR) at CUSAT has been leading over the past five years.
The project brings together a multi-disciplinary research team that includes social scientists, physical geographers, atmospheric and marine scientists, and communication and media experts from CUSAT and the University of Sussex. The project aims to improve safety at sea for small-scale traditional fishers by producing and communicating localised weather forecasts.