Sea Level Rise and Cyclonic Hazards in Peninsular India

Gautam Kumar Das

World-wide or regional available data for sea level rise is in contradiction with what different agencies and organizations published officially, yet sea level is rising and alarming. Of late data on sea level rise along the coastal stretch of peninsular India, released by Ministry of Earth Sciences, Government of India, shows that the sea levels have risen by 8.5 cm during the past 50 years at the rate of 1.7 mm per year. The data of 10 major port areas across the country averages 1.7 mm a year, though this long-term data collected is in different duration for different locations such as 28 years for Okha and 128 years for Mumbai. The scientists of the Ministry of Earth Sciences, Government of India collected data from different locations like Kandla (Gujarat), Okha (Gujarat), Mumbai (Maharashtra), Kochi (Kerala), Chennai (Tamil Nadu), Vizag (Andhra Pradesh), Port Blair (Andaman and Nicobar Islands), Paradeep (Orissa), Haldia (West Bengal) and Diamond Harbour (West Bengal). Such data on sea level change indicates the highest of annual average rise at Diamond Harbour at the rate of 5.16 mm per year and the lowest at Chennai at the rate of 0.33 a year. As the data have not been collected for all locations in the same duration, the researchers of the Ministry of Earth Sciences, Government of India considers the computation of data for sea level rise requires a greater accuracy, yet the officials of the ministry like to give an idea on sea level rise around peninsular India. Climate change and global warming are the most appropriate reasons raised for such sea level rise as stated by the team of central agency under Government of India. Simultaneously almost all the agencies working together with the United Nations, an international body, are all agreed on the rise of sea level in accelerating manner and published the data of sea level rise at the rate of 3.6 mm per year globally in their latest report of UN’s Intergovernmental Panel on Climate Change (IPCC).

Data on sea level rise at 10 locations along the coastal stretch of India

 Source: Ministry of Earth Sciences, Government of India

On contrary to this data published by Ministry of Earth Sciences, Government of India, researchers like P K Bhaskaran, NNV Sudha Rani and ANV Satyanarayana of Ocean Energy and Naval Architecture Department, IIT, Kharagpur indicate comparatively slower rate of sea level rise in their publication titled ‘Assessment of Climatological Trend of Sea Level over the Indian Coast’ published very recently in the journal ‘Pure and Applied Geophysics’. In their paper, they have shown that the Bay of Bengal is rising 3.6 times faster than Arabian Sea mentioning Kolkata faces bigger flooding risk than Mumbai. The authors carried out their study on sea level rise in 2017 using 30 years’ tidal gauge data from Kandla, Mumbai and Cochin in the west coast of India and Diamond Harbour, Haldia, Visakhapatnam and Chennai in the east coast of India. The authors indicate that the sea level in the Bay of Bengal is rising at 1.35 mm per year against the rise by 0.37 mm a year in the Arabian Sea showing the eastern coast of India is much more vulnerable that of the western coast due to rising of the sea level.

As a result of rising sea level due to global warming and climate change, the Indian Meteorological Department, after computation of the yearly occurrences of the storms, states that the numbers of severe cyclones increasing by 11 percent in the last decades in the Arabian Sea and the Bay of Bengal. Further, the Indian Meteorological Department alerts the inhabitants living in the coastal stretch across the Indian peninsula for frequent occurrences of severe cyclones with 32 percent rise in the last five years duration in the Bay of Bengal and Arabian Sea.

List of tropical cyclones occurred in the year 2019 that affected India and its neighbourhoods

For such gradual rising of sea level, the vulnerable coastal land of peninsular India is of late considered as unsafe for living, as on average, four cyclones ravaged coastal India each year during the period from 2010 to 2019. Though coastal stretch considered as cyclone-hit area, living closer to the sea is good for mental health as protective zone for psychological wellbeing where ‘Blue Health’ should be the only link between health and the natural environment, published in a journal ‘Health and Place’. Researchers from Exeter University suggest living close to the sea could help to reduce mental health disorder particularly for those who live less than a kilometer from the coastal zone. Keeping all these merits and demerits with alertness, in fact, the concerned local government involves responsibility with the approaches towards appropriate disaster management and trains tolerance practices as the coastal population at risk is increasing annually.

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Dec 11, 2019