Sea Level Case Study

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One of the multiple changes that is anticipated as a result of an anthropogenically warmed global climate is a rise in sea level. Mean global sea-level has already begun rising; over the 20th century mean sea-level rose 0.17 metres (0.12 metres – 0.22 metres). Significantly the rate of this rise was seen to accelerate towards the end of the century. What is modelled in this study is observed sea-level, which is a function of mean sea level, tidal influences and meteorological forcing of the mean sea-level. All three components of observed sea-level are subject to change. The three chief factors contributing to changes in mean sea-level are: (i) thermal expansion of the top 3,000 metres of the ocean. This section of the ocean absorbs 80 per…show more content…
The sea level rise is highly variable both -in terms of time and space. Various estimates for the Indian . coast vary from 0.5 to 2.2 mm per year. It is expected that the rise in sea level will lead to erosion, tidal shift, • sea water ingression and degradation of the coastal • ecosystem. The Indian coast is a 'trailing edge' coast and hence it is low-lying, with extensive sedimentary plains and wide continental shelves. Thus the projected relative sea level rise would likely affect this type of coast. The . response of different ecosystems to sea-level rise has been : evaluated based on their characteristics for the Gujarat coast (Nayak, 1994). Lowlands comprising barren mudflats may be inundated and eroded as they comprise loose or less compacted sediments. In estuarine areas, the tidal amplitude will increase and bring changes in the current pattern. The human activities have significantly • altered the sediment transport from land to estuaries. In : a flat and low-lying area, high tide line will move landward and inundate intertidal slopes. In such areas, the .• mangroves will colonise the adjoining unvegetated tracts. Large areas in deltaic regions have degraded mangroves. They have been degraded mainly because of anthropogenic activities. The sparse mangrove will not be able to trap sufficient sediments to make new land. In such areas, the mangroves will be further…show more content…
As a consequence, they are unable to comprehensively integrate coastal hazard risk and sea level rise into their decision making in order to increase the resilience of human and natural communities. Subsidence is caused by tectonic activity, extraction of ground water and the disruption of sediment deposits in estuaries caused by upstream dams and weirs. Subsidence induced sea-level rise is typically small (10mm per year according to Church, 2001) in comparison with changes projected by climate change, and is not covered in detail in this report. Hence we have assumed that factors like Subsidence Storm Surge etc. remain constant. The City’s coast provides a range of social and economic opportunities including recreational and amenity areas, sought after housing and development opportunities as well as core economic attributes. In addition, the City’s coast is a dynamic ecological system that supports a wide range of species, ecological systems and ecological services. Global climate change predictions suggest that amongst others, sea level rise and an increase in the intensity and frequency of storm events may have significant impact on coastlines across the

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