Wednesday, 30 May 2012

Assessing the Risk of Sea Level Rise: The Way Forward for Sri Lanka

By S.S.L.Hettiarachchi and S.P.Samarawickrama
Department of Civil Engineering, University of Moratuwa

Climate Change and Sea Level Rise  
Climate change will have significant impacts on the oceans and on the coastal zone on a global scale. It will introduce new hazards and increase existing hazard potential, both with respect to magnitude and frequency of occurrence, in coastal regions. The hazards would be both chronic (e.g., sea level rise) and episodic (e.g., storm events). Sea level rise is one of the more certain responses to global warming and presents a major challenge in the administration and management of coastal zones, including that of Sri Lanka. A large percentage of Sri Lanka’s population is located in coastal regions and these regions play a vital role in the economic growth of the country.

Sri Lanka is one of the few countries which have a fully operational National Coastal Zone Management Plan, and the Government’s Coast Conservation Department has  full responsibility for its implementation. In Sri Lanka, the Coast Conservation Act has defined the coastal zone on geo-physical considerations using linear dimensions. This narrow and geographically defined coastal zone does not recognize the interconnections within coastal ecosystems, its resources, and the human interactions. This limitation in the definition of the coastal zone could become a critical constraint when implementing action plans to respond to sea level rise in the country.

Analyzing the Impacts of Sea Level Rise 
Investigations conducted in Sri Lanka have revealed that climate change will result in changes to critical forcing parameters of the coastal zone which would affect the physical condition of the shoreline. Rising sea levels, change in wave patterns arising from changes in wind pattern and water depth, increased rainfall and the occurrence of extreme events more frequently, are some of these. Sea level rise on its own would lead to several issues:      

        (i)  Inundation and displacement of low lying coastal areas and wetlands
       (ii)  Coastal erosion and degradation of shorelines
       (iii) Salinisation of estuaries and freshwater aquifers, and
       (iv) Changes to and migration of coastal eco-systems and habitats.