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Economic costs of long-term sea level rise on the Oregon coast: A case study of the Siletz Littoral Cell

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Disciplines
  • Design
  • Earth Science
  • Economics

Abstract

Given the broad scientific consensus that global climate is changing, it is no longer a question if sea level will rise, but rather by how much will it rise. The regional estimates for the Eastern Pacific suggest that the Northwest coastlines will experience a greater eustatic sea level rise than most areas, with 50-year estimates of sea level rise on the order of 0.3 meters. This rise in sea level, while not extraordinary, will exacerbate an already ongoing coastal erosion problem in the region. The majority of Northwest ocean shoreline is experiencing tectonic uplift that more than negates the effects of sea level rise. However, there are portions of the Oregon coast that have essentially zero uplift and it is these locations that are already experiencing severe episodic erosion problems. The typical response to coastal erosion along the Oregon coast has been to install hard shore protection structures (SPSs). The Siletz littoral cell, the case study, is one such case. It is one of the most developed portions of the Oregon coast and is already more than half protected by SPSs. The trend for this area has closely mimicked episodic climatic events in that after such events there are bursts of SPS construction. The risk with such an approach is that there will, over the long-term, be a narrowing and eventual loss of oceanfront beaches. Because the Oregon coast is highly dependent on tourism and travel for its economic base, the loss or decrease in the beach resource would have a substantial effect on the region's economy. More than 2 million visitors recreate annually just within our case study area—the Siletz cell beaches. There have been attempts to place economic value on non-consumptive uses such as beach recreation in other parts of the country, but not in the Pacific Northwest. Given the potential adverse impacts of fixing the shoreline in place with hard SPSs, this option designed to protect uplands (not beaches) should not be the only management choice utilized to address the issue of coastal erosion in the region. This project starts the process of comparing other options to the typical option of hardening, from an economic perspective. An analysis of the different options was conducted for 20-year and 50-year scenarios. The results show that in the 20-year scenario, the 'protect' option is clearly the least costly option due to the existing high levels of development and it makes economic sense to protect the existing infrastructure. However, the results for the 50-year scenario show an interesting cost shift taking place between two of the options. The low range of the 'retreat' option is now more favorable economically then the low end of the 'protect' only option. The conclusion is that over a longer time frame, it simply becomes costlier in losing more beach visitors than it is to continue protecting the existing infrastructure.

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