해수면 상승에 따른 취약성 분석 및 효과적인 대응정책 수립 I

Abstract

Vulnerability Assessment of the Korean Coast due to Sea-level Rise and Appropriate Response Strategies I-Assessment of Shoreline Retreat The overall objective of the study is to contribute to the sustainable development of the coastal zone through the integrated assessment of coastal erosion, flooding/inundation, estuary sedimentation, and saltwater intrusion due to sea level rise and other factors induced by climate change. For the first year study, we calculated the shoreline retreat rate due to sea level rise, used that value as a “vulnerability index“, and presented basic response strategies. Based on the satellite altimeter data of the NASA Topex/Poseidon and Jason from 1993 to 2008, sea levels in the Korean waters have been rising at an average rate of 4.02 mm/yr (30% higher than the global mean of 3.16 mm/yr). The Southern Sea has shown the highest increase of 4.66 mm/yr versus the West Sea (4.18 mm/yr) and East Sea (3.86 mm/yr). Wave and Typhoon along the Korean coast have also increased. The retreat of shoreline was quantified with the cross-sectional data of 111 sandy coasts (including 44 on the east coast, 32 on the south coast, and 35 on the west coast), with 3 cross-sectional profiles for each beach. The “equilibrium beach profile” method was used to assess the retreat rate of shoreline, and the applicability of the theory into the Korea coast was testified via 15 cross-sectional beach profiles. We devised four scenarios of future sea level rises: 38cm, 59cm, 75cm, and 100cm. The overall shoreline retreat rate for the Korea coast was found to be 43.7% at 38cm, 60.3% at 59cm, 69.2% at 75cm, and 80.1% at 100cm sea level rises, respectively. The east coast, a retreat rate of 29.6% at 38cm, 45.1% at 59cm, 56.0% at 75cm, and 69.9% at 100cm, showed a relatively low rate that the south coast at 51.9%, 67.6%, 77.2%, 87.3% respectively, as well as the west coast at 53.8%, 71.0%, 78.5%, 86.4% respectively. However, all Korea's beaches were found to be vulnerable with increasing sea levels. The study does, however, maintain some uncertainties with respect to its conclusions. These uncertainties include limitations of the assessment model and gaps in the spatio·temporal data in the beach profiles, as well as changes in future climate scenarios. The study considers only future sea level, but resulting coastal erosion could play out differently due to wave, storm surge, and precipitation changes. In this light, Korea will need more integrated efforts to respond to coastal erosion including continuous and comprehensive observations, and development of greater scientific understanding in the field. Korea's coast has been stressed by human interventions, and such stress would be further intensified with the accelerating climate change in this century. Thus, new environmental objectives to deal with coastal erosion will need to be established, and the requisite technical and institutional options should be reviewed and incorporated to archive the target. Strategies for dealing with coastal erosion should be based on the maintaining and/or restoring the physical and geological function of coast, with respect to which the example of developed countries in Europe can provide guideline. Such strategies may be quite challenging in Korea, with its highest density of coastal development but active research and discussion should be promptly initiated to provide more effective adaptation to climate change and increasing sea levels