Chapter 6. Impacts of Climate Change on Oregon's Coasts and Estuaries in "Oregon Climate Change Assessment Report"
Citation:
RUGGIERO, P., C. A. BROWN, P. KOMAR, J. Allan, D. REUSSER, AND H. LEE. Chapter 6. Impacts of Climate Change on Oregon's Coasts and Estuaries in "Oregon Climate Change Assessment Report". U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-10/184, 2011.
Impact/Purpose:
Earth’s changing climate is expected to have significant physical impacts along the coast and estuarine shorelands of Oregon, ranging from increased erosion and inundation of low lying areas, to wetland loss and increased estuarine salinity. The combination of these processes and their climate controls are important to beach and property erosion, flood probabilities, and estuarine water quality, with the expectation of significant changes projected for the 21st century. Evaluating the consequences of intensified and more frequent hazards is complicated by Oregon’s tectonic setting, with there being significantly different rates of land uplift along the coast. Taken together, the variable rate of uplift plus the present-day rate of sea level rise, some stretches of the coast are submerging as the sea-level rise is greater than the tectonic uplift, whereas other areas are emerging where the reverse is true. Another long-term trend is increasing storm intensities and the heights of the waves they generate. In addition, the periodic occurrence of major El Niños in the future will compound the impacts of increasing sea levels and waves, resulting in severe episodes of coastal erosion and flooding. At present it is not known whether or not El Niño intensity and frequency will increase under a changing climate. It is likely that regional coastal climate change will result in changes in the intensity and timing of coastal upwelling, shifts in temperatures and dissolved oxygen concentrations, and alteration of the carbonate chemistry (ocean acidification) of nearshore waters. The combination of these meteorological and nearshore ocean changes will exert stress on the communities of near-coastal and estuarine organisms. The range of community responses to the climate change stressors may include elevational shifts in the distribution of submerged aquatic vegetation, disruption of shell formation for calcifying organisms, alteration of the phenology of phytoplankton blooms, shoreward migration of tidal marshes, and increased colonization by non-indigenous aquatic species. Unfortunately, significant knowledge gaps remain, impairing our ability to accurately assess the impacts of climate change along our coast and estuarine shorelands. At present we do not conclusively understand the climate controls on increasing storm intensities and wave heights and therefore have a very limited ability to project future trends in coastal storm impacts. The magnitude and frequency of major El Niños has significant implications for the state of Oregon, however, at this time we are unable to assess whether or not these will increase in the future due to climate change. Further, the long-term time-series data necessary to definitively identify perturbations of estuarine communities that can be attributed to anthropogenic climate change are lacking and therefore our understanding of anticipated shifts remain largely speculative.
Description:
In 2007 the Oregon legislature created a new Oregon Climate Change Research Institute (OCCRI), which is based at Oregon State University (OSU). As part of its charter, OCCRI is mandated to produce a biennial report for the state legislature synthesizing climate change impacts and research within Oregon. Because of their ongoing research on estuarine climate change, WED scientists were invited to contribute to Chapter 6, which focuses on the physical and chemical impacts of climate change on near-coastal and estuarine environments. As pointed out in the chapter, “The environmental changes associated with climate change include rising sea levels, increased occurrences of severe storms, rising air and water temperatures, and ocean acidification. The combination of these processes and their climate controls are important to beach and property erosion, flood probabilities, and estuarine water quality, with the expectation of significant changes projected for the 21st century.” Dr. Brown of the WED took the lead for synthesizing climate effects on estuarine water quality, including temperature, salinity, dissolved oxygen (DO), nutrients, and changes in pH (ocean acidification). One of the overarching conclusions from this synthesis is that climate effects on estuarine water quality will depend strongly upon changes in ocean processes, such as the timing and intensity of upwelling and advection of low DO ocean water into estuaries. The WED scientists and their USGS partners also took the lead in synthesizing the current state of the science in predicting changes in tidal wetland habitats in response to sea-level rise using “Sea Level Affecting Marshes Model” (SLAMM). The overall conclusion from this evaluation is that SLAMM is of potential management utility but should be modified to better capture the dynamics of Pacific Northwest estuaries. In 2007 the Oregon legislature created a new Oregon Climate Change Research Institute (OCCRI), which is based at Oregon State University (OSU). As part of its charter, OCCRI is mandated to produce a biennial report for the state legislature synthesizing climate change impacts and research within Oregon. Because of their ongoing research on estuarine climate change, WED scientists were invited to contribute to Chapter 6, which focuses on the physical and chemical impacts of climate change on near-coastal and estuarine environments. As pointed out in the chapter, “The environmental changes associated with climate change include rising sea levels, increased occurrences of severe storms, rising air and water temperatures, and ocean acidification. The combination of these processes and their climate controls are important to beach and property erosion, flood probabilities, and estuarine water quality, with the expectation of significant changes projected for the 21st century.” Dr. Brown of the WED took the lead for synthesizing climate effects on estuarine water quality, including temperature, salinity, dissolved oxygen (DO), nutrients, and changes in pH (ocean acidification). One of the overarching conclusions from this synthesis is that climate effects on estuarine water quality will depend strongly upon changes in ocean processes, such as the timing and intensity of upwelling and advection of low DO ocean water into estuaries. The WED scientists and their USGS partners also took the lead in synthesizing the current state of the science in predicting changes in tidal wetland habitats in response to sea-level rise using “Sea Level Affecting Marshes Model” (SLAMM). The overall conclusion from this evaluation is that SLAMM is of potential management utility but should be modified to better capture the dynamics of Pacific Northwest estuaries.