The coastal communities that are vulnerable to sea-level rise due to climate change also have to worry aboutwave activity.
The extreme wind-wave pattern directly correlates with the location of intense wind activity, a recent study by Indian scientists has indicated.
These regions over the Bay of Bengal, the South China Sea and the South Indian Ocean can experience higher wave activity in the future, posing a severe threat to coastal communities in the region.
These communities are already most vulnerable to the impact of climate change and other environmental drivers due to their exposure to severe inundation and its frequency associated with extreme water levels in the nearshore regions apart from facing increasing instances of cyclones.
The impact resulting from coastal inundation can significantly affect the shoreline configuration, damage infrastructure, saltwater intrusion into groundwater, destroy crops, and affect the human population with various socio-economic consequences. Scientists worldwide are trying to estimate the magnitude of this impact, a release from the Union Ministry of Science & Technology said.
The present study performed a detailed investigation on future extreme wind-wave projections and their relationship with wind speed, sea level pressure, and sea surface temperature for the mid-and end-century under two different greenhouse gas emission scenarios projected by the Intergovernmental Panel on Climate Change (IPCC) called RCP4.5 and RCP8.5 (possible climatic conditions depending on varying levels of global temperatures rise then.
An analysis of the projections has indicated maximum extreme wind and wave activity over the South Indian Ocean region during June-July-August and September-October-November. Areas over the central Bay of Bengal show intense wind activity from the end-century projections, signifying the likelihood of more extreme events. Extreme wave heights intensify by about 1 m over the South Indian Ocean during the June-July-August months.
An increase of 0.4 m in maximum significant wave heights are projected over regions in the North Indian Ocean, the northwest Arabian Sea, northeast Bay of Bengal, and the South China Sea.
A team of scientists, Athira Krishnan and Prasad K Bhaskaran from the Department of Ocean Engineering & Naval Architecture, IIT Kharagpur, jointly with Prashant Kumar, Department of Applied Sciences, National Institute of Technology, Delhi, with support from the Department of Science & Technology, Government of India under the Climate Change Programme (CCP), carried out this study, which was published in the journal 'Climate Dynamics', Springer recently.
Findings from the study show that the projected change in wave heights are maximum for the South China Sea in RCP4.5, whereas the total rise is about 23 per cent in RCP8.5 by the end of the end-century. Also, the projected change in winds and waves over the western tropical Indian Ocean is consistent with changes in sea-level pressure variations and warm ocean temperatures. A significant increment in sea surface temperature is projected over the Arabian Sea during December-January-February and June-July-August months ranging between 1.5 and 2.0 degrees Celsius that, is 0.5 degrees Celsius greater than the Bay of Bengal. Projections show that regions over the Gulf of Oman and the Persian Gulf can experience higher warming rates exceeding 2 degrees Celsius under RCP8.5 by the end of the century.
The new findings from this study are expected to augment more advanced research on extreme wind-wave activity for the North Indian Ocean region and provide the scope for a detailed investigation on the possible linkages and teleconnection with climate indices in a changing climate.
