Climate change likely to increase extreme wave events in Indian Ocean: Study

New Delhi: A recent study has shown that extreme wave events are likely to occur in the Indian Ocean, the northern sector of the Arabian Sea, and the central Bay of Bengal.

The study also revealed that the region will also likely experience an increase in “rough wave days” in the near future.

The research published in the journal ‘Climate Dynamics’, by Springer recently has shown that large-scale distribution in future wave climate can vary significantly from the present.

“In a changing climate, 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,” the report said.

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.

Extreme waves due to climate change and its consequences continue to emerge at both regional and global scales.

Hence, 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.

The report claimed that the new study could help timely warning and planning to prevent major impacts on life and property, especially in coastal areas.

A team of scientists from the Department of Applied Sciences, National Institute of Technology Delhi; Indian Institute of Technology Kharagpur; and Indian National Centre for Ocean Information Services, Hyderabad, projected the likely future changes in “extreme wave height indices” over the Indian Ocean.

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

However, under a 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 an exception for regions in the north Arabian Sea and extra-tropical regions beyond 48° S in the Southern Indian Ocean sector.

Changes in high wave days are projected to intensify over the 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 RCP 8.5 forcing scenario.

The study indicates 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.