Impact of Sea Level Rise

For centuries, the coastline has been a focus for a variety of activities including industry, agriculture, recreation and fisheries. The coastline is a national heritage and in order to sustain it for future generations, proper management of coastal resources and defense is essential. The short and long term variations in sea level impact the coastal ocean in many different ways. Long term sea level rise is expected to have a significant impact on the straight coast as well as islands, barrier reefs, entrance processes of river estuaries, inlets, bays, coastal lagoons, etc, which will subsequently have a cascading effect on environmental processes of these coastal environments.

Mean sea level, on a global scale, has been increasing over the past century, approximately 1.8mm/yr due to the thermal expansion of the oceans  and glacial melting.  IPCC (2007) project an increase in mean sea level of between 0.18 and 0.59m by the end of the 21st century, with the possibility of an additional 0.1 to 0.2m due to ice sheet flow. This would lead geomorphic evolutionary processes on the coast, including the landward transgression of coastal barriers.

a) Objectives:

Study the impacts of sea level rise on coastal geomorphology and geometry.  Some of the local scale shoreline changes especially causing erosion/accretion in the selected islands of Lakshadweep will be studied so as to explore feasible structural/non-structural protective/adaptive option(s

b) Participating Institutions:

1. National Centre for Coastal Research (NCCR), Chennai
2. Indian National Centre for Ocean Information Services, Hyderabad
3. Indian Institute of Tropical Meteorology, Pune
4. Academic and R & D Institutions

c) Implementation Plan:

1. Assess the factors attributable to the sea level changes through a comprehensive studies
   • associated with the change in volume of the Indian Ocean basin in terms of sea water density (steric), salinity (halosteric), temperature (thermosteric) and change in mass due to glacier/ice melting (Eustatic)
   • associated with the changes to the shape of the Indian Ocean geometry due to vertical displacement of land (tectonic) and deltaic subsidence
2. Classify coastal environments based on tidal oscillations and using relative wave/tide energy, fluvial discharge in a temporal framework including transgression and progradation.
3. Studying changes in sea level and its impact on shoreline migration.Carbon dating and age determination based on bore hole samples and identifying sediment depositional trends – deriving brief overview of the Indian coastal zone based on sediment supply and geologic heritage (antecedent geology) such as Quaternary sea level history.
4. Beach profile measurements to study the changes in beach volume in the event of erosion caused by rise in sea level and predict the extent of loss of beaches - Sediment transport and associated models to assess the fate of lost sediments
5. The proposed programme is an integrated approach based on utilization of expertise from physical, chemical, biological and geological scientists together with scientists working in remote sensing and will be implemented by NCCR

d) Deliverables

1. Development of zone-specific coastal zone circulation models and impact assessment tools
2. Quantification/Assessment of the factors contributing to the manifested sea level rise over the Indian Ocean and assess the associated impacts over the Indian coastline

e) Budget requirement : 7 crores*

(Rs. In crores)

* Amount projected is part of  Rs.185 cr of  3.6.5. Coastal Research