Human influences, ecological transitions and uncertainties of extrapolation of risks of selected sea level rise scenarios to India's coastal megacity, Cochin

Despite the magnitude and urgency of the issue, scientific understanding of climate change and potential risks to Indian coastal cities have not been fulfilled till recently; though it has long been recognized world wide that regional and global perspectives on the potential impacts of climate change are required for a range of purposes, including communicating the likely implications to a non-specialist audience, examining the costs and benefits of different mitigation adaptation policies and identifying regions where collective action could be beneficial. This study presents the results of the combined analysis of impact assessment studies of the coast and coastal structures around Cochin, along the south-west coast of India. From the results obtained, it has been found that the effects of climate change and associated sea level rise scenarios will have a profound effect on the coast as well as on the coastal sedimentary environments and the land loss occurring will be significant. The study also revealed that mean beach slope and relief play a controlling factor in land loss in the region. As sea level rises, the local relief of the coastal zone will decrease, thus increasing the percentage of land above mean sea level subject to episodic inundation from tropical cyclones, The monetary losses involved will be significant, as the amount of coastal property inundated due to flooding will increase considerably. Results of the yearly probability of damage indicates the need to upgrade the existing designs of coastal protection structures. A brief characterization of the issues of uncertainties on policy and planning is also attempted