American Estuaries: An Assessment of Characteristics & Climate Change Risk

• In Event: Developing Collaborative Environmental Policy Solutions in a Warming World

Abstract

Estuaries in the United States are not just critical ecosystems but also economic juggernauts. Estuary regions contain eight of the ten largest U.S. cities with economic output in these areas accounting for 47% of national GDP. Estuaries are also cultural spaces of great significance, both for the diverse communities that surround them and to Indigenous nations that have held deep connections to these bodies of water for millennia. Geographically complicated and containing overlapping political jurisdictions with complex public management regimes, American estuaries present an ideal landscape for mixed methods research to answer important policy research questions.

This study focuses on the National Estuary Program (NEP), administered by the U.S. Environmental Protection Agency (EPA). The EPA provides funding, guidance, and technical assistance to 28 NEPs nationwide. NEP management plans, however, are designed according to local priorities by local governing bodies. The geographic boundaries and ongoing management priorities are established collaboratively by local, city, state, federal, and private/industry stakeholders.

Given the important economic and cultural relevance of U.S. estuaries, we first explore the extent to which these regions present specific cases of vulnerability (e.g., economic and health outcomes) that warrant attention from policymakers as the climate warms. Likewise, we employ Census tract data (e.g., population, income, education, etc.) to investigate spatial variations in contemporary demographic, economic, and social characteristics of individuals residing within NEP boundaries.

A Spatial Durbin Model is employed to characterize climate risk within each regional NEP. This model was selected because spatial dependence tests revealed its presence in both the dependent variable and error term. Climate risk, the dependent variable, was measured using the National Risk Index (NRI), produced by the Federal Emergency Management Agency. NRI values represent a Census tract’s relative risk to natural hazards. They are calculated based on the expected annual economic loss (resulting from natural hazards), a community’s social vulnerability, and a community’s resilience.

By implementing fixed effects for each of the 28 NEPs, the spatial model reveals which locations are at the highest climate risk. These results inform the second stage of analysis, in which the 10 NEPs most at risk to climate change were contacted to initiate an interview protocol. This qualitative analysis will investigate the extent to which variation in stakeholder engagement is observed relative to climate risk. For instance, do NEPs with higher NRI values correspond with greater engagement and more robust community collaboration? Through document analysis and interviews with NEP stakeholders, we will explore how climate risk shapes the approaches to collaboration and the use of scientific knowledge in those collaborative processes.

This study makes two important contributions. First, we provide a clear empirical roadmap for how to use spatial data analysis combined with robust Census data to outline the demographic, economic, and social implications of climate risk as a function of community and NEP characteristics. Second, we shine light on the important policy implications that emerge from the negative economic, environmental, and social consequences that climate change is likely to have on estuarian regions.

Authors

• Mark Nepf, University of Washington
  Presenting Author

• Yulan Kim, University of Washington
  Presenting Author

• Grant Blume, University of Washington
  Non-Presenting Co-Author