Sea Level Rise Addressed in Environmental Impact Statements

By Patrick Woolsey, CCCL Intern

The issue of sea level rise (SLR) related to climate change is increasingly being addressed in federal environmental impact statements (EISs) for coastal projects. As described in a previous post, the Center for Climate Change Law (CCCL) has prepared a database of EISs that address climate change-related impacts. The database categorizes the climate change-related impacts considered in the EISs and organizes them by project type and lead federal agency. While many EISs now address cumulative climate change impacts to some degree, the methodology and extent of the analyses vary greatly by agency and project type, as illustrated by several examples of the treatment of sea level rise in EISs involving coastal projects.

The U.S. Army Corps of Engineers now considers SLR in many EISs involving ports and coastal waterways. For example, a 2010 EIS for the Mississippi River Gulf Outlet Ecosystem Restoration Study in Louisiana provides a comprehensive analysis of climate change impacts on SLR. This coastal wetlands restoration plan considers the likely impacts of SLR on wetlands in the Mississippi delta, including submersion, subsidence and shoreline retreat, and discusses mitigation measures which may reduce wetlands loss. It also considers the effect of intensified storm surges, risks to the New Orleans metropolitan area, and the effect of saltwater intrusion on freshwater habitat and drinking water supply. While citing high scientific uncertainty about the degree of SLR, the EIS uses available modeling techniques to produce projections through the end of the century and calls for further study of the issue.

The issue of SLR is also addressed in EISs produced by the Nuclear Regulatory Commission for coastal nuclear reactors. A 2011 EIS for the relicensing of the Seabrook Nuclear Station in New Hampshire discusses projected SLR and its potential impacts on the reactor site. The EIS addresses the relationship between climate change and SLR, and analyzes SLR impacts including potential damage to the reactor from storm surges or flooding of nuclear fuel storage areas. In addition to risks to reactor safety and security posed by SLR, the EIS also addresses impacts on marine ecology and the threat posed to water supplies from saltwater intrusion.

Sea level rise is addressed in a different context in EISs for fishery management plans produced by the National Oceanic and Atmospheric Administration. A 2011 EIS for a fishery management plan for the Spiny Lobster addresses the effect of depth changes from SLR on shallow-water species like corals and on coastal habitats, mentioning that it would affect nesting habitat for sea turtles. A paragraph of generic language on the causes and effects of SLR is used throughout the report to discuss SLR impacts on various marine species. Several other agencies have also developed standard language regarding SLR which now appears in all coastal project EISs.

The U.S. military addresses sea level rise in its EISs for coastal bases and installations with particular urgency. In a 2010 EIS, the Navy analyzes the effects of SLR on the expansion of a naval base on the island of Guam and the construction of a deepwater docking facility for aircraft carriers. The Guam EIS recognizes the island’s extreme vulnerability to climate change and SLR. The EIS also discusses SLR in the context of broader security concerns, noting that “in 2008, the National Intelligence Council judged that more than 30 U.S. military installations were already facing elevated levels of risk from rising sea levels.”

While the EISs discussed are examples of exceptionally thorough analyses of SLR, the issue is often addressed far more briefly in EISs produced by other agencies such as the Bureau of Ocean Energy Management, Regulation and Enforcement. However, the EIS database prepared by CCCL shows a general trend towards more thorough analysis of sea level rise from climate change and the increasing severity of its projected impacts on coastal areas.

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