Climate change likely to increase rough wave days in near future: Study

According to a recent study of extreme wave events by the Department of Applied Sciences, National Institute of Technology Delhi; Indian Institute of Technology Kharagpur; and Indian National Centre for Ocean Information Services, Hyderabad, extreme wave events that have been recorded quite frequently during recent times can pose a tremendous impact on the livelihoods of the coastal population, infrastructure, and ocean-related activities.

“Observed variability and changes in extreme wave events, along with shifting storm intensity and tracks, can play a crucial role in shoreline changes, erosion rates, flooding episodes, and other related coastal hazards.”

The study added that extreme waves due to climate change and its consequences continue to emerge at both regional and global scales. “A better understanding of the future projected changes in the amplitude of high-frequency extreme wave events is necessary for timely warning and coastal planning and management.”

“Future projections indicate that under the climate scenario RCP4.5 (medium representative concentration pathway of greenhouse gases), the regions over eastern tropical Indian Ocean, northern sector of Arabian Sea, and central Bay of Bengal showed a strong positive increase in rough wave days.”

Under high-emission scenario corresponding to RCP8.5, a decreasing trend in rough wave days is likely over most of the regions in the Indian Ocean, with exception for regions in the north Arabian Sea and extra-tropical regions beyond 48° S in the Southern Indian Ocean sector, the study said.

Changes in high wave days are projected to intensify over South Indian Ocean under both RCP 4.5 and 8.5 scenarios, and the wave-spell-storm duration is found to strengthen over the northern Arabian Sea and Bay of Bengal, southeast Indian Ocean and South Indian Ocean under RCP8.5 forcing scenario.

The study indicated that projected changes in the amplitude of high-frequency extreme wave events in the Southern hemisphere are driven by changes in a sea-level pressure gradient that is consistent with the projections of SAM (Southern Annular Mode) for the twenty-first century period.

The research is supported by the Science Research and Engineering Board (SERB), an attached institution of the Department of Science & Technology (DST), Government of India.