Bhubaneswar: The shoreline map of the port town of Paradip seems in grave danger.
With the town having to brace up for more tidal hits and severe coastal erosion in years to come, the threat of Pardip going under water in next two decades looms large.
The future tense scenario for the port town is attributed to the rising Bay of Bengal.
As per Ministry of Earth Sciences report, when the Bay of Bengal is rising at the rate of 3.8mm every year, the sea-level rise measured by gridded satellite altimeter records (1993-2020) at Paradip shows a rise of 4.43 mm every year.
The MoES reports states that the rise of sea level at Paradip during the last 27 year period has been 4.43 plus or minus 0.36 per year.
Rise of sea-level at Paradip seems to be highest along the east coastline of the country. View the details below.
- Chennai – 4.31mm/yr
- Vishakapatnam – 4.27mm/yr
The eye-popping sea rise at Paradip is the second highest for any coastal place in the country, after Mumbai, where the sea level is rising at 4.59mm/year
If the above measured data during the last 27 year period needs to be taken into account, then the sea level at Paradip has risen by a whopping 10.8cm during the last 27 year.
The thumb rule known as Brunn rule suggest that a 1cm rise in sea level will lead to 1meter retreat of coastline.
Going by the Brunn rule, Paradip coastline might have recorded a retreat as high as much as 10mts during the last two decades.
Therefore, as the trend continues, or may aggravate in coming years say NASA report, it seems the coastline of Odisha’s Paradip is under severe threat of submerging under sea water.
HOW SEA LEVEL RISE MEASURED?
According to the MoES report, Sea level is measured in either of the ways.
- With respect to the surface of the solid Earth, known as relative sea level (RSL)
- Geocentric reference such as the reference ellipsoid, known as the geocentric sea level.
- RSL estimates have been obtained from tide gauges
- Geological records for the past few centuries.
- Geocentric sea level has been measured over the past two decades using satellite altimetry.
- This Geocentric sea level measurement has estimated the 2nd highest seal level rise at Odisha’s port city Paradip.
WHY SEA LEVEL RISING?
As per studies by MoES, while the surface waters of the Bay of Bengal get heated due to rising heatwaves during the summer, the BoB is unable to transfer the high surface temperature deeper to cool down or say maintain the heat balance, as the wind circulation during the Monsoon over the BoB has been weaker unlike the Arabian sea where strong wind during monsoon results in vertical movement of heat within ocean - which is proving dangerous to Mumbai.
So, the high sea-level rise around Paradip might be solely attributed to thermal expansion of the Bay of Bengal. Future holds no promise.
2024 NASA STUDY
The recent NASA release sounds more scary. The NASA study shows from 2024 onwards, oceans around the world are experiencing high degree of thermal expansion, faster than ever before.
The study said, “In 2024, two-thirds of sea level rise is coming from thermal expansion. The increased thermal expansion is attributed to deeper layer warming of oceans.”
NASA report further warned: Deeper layer warming of oceans will lead to intensified cyclones, and faster rise of sea-level.
So, vertical movement of heat in Bay of Bengal will lead to greater than ever thermal expansion in coming years.
IMPACT ON PARADIP
The biggest threat the port town faces from faster rise in sea level at its doorstep will be coastline erosion due to sea incursion.
Moreover, as the city has borne the devastative 1999 super cyclone, when 30 feet height tides simply washed away villages after villages, the rising sea level would acerbate its vulnerability more to impending cyclones.
As per IMD report, a high water level plus a storm surge on top leads to a storm or “king” tide. In combination with storm waves, it can cause significant coastal erosion and flooding, in case the city comes under the sweep of any future cyclone.
Another mega impact on the coastal town will be salinity attack.
When sea water level rises, saltwater may intrude into freshwater acquifers leading to salinisation of groundwater, which may have a very deleterious impact on agriculture in the district.
