Like many coastal regions, ecosystems in the North Coast and Humboldt Bay face a number of threats from climate change and sea-level rise, including:
Nearly 41 miles of dikes on Humboldt Bay are vulnerable to being breached by extreme tides and water elevations, with nearly 7,000 acres currently at risk of being inundated with saltwater. Assuming 1.0 meter of sea level rise, the mean annual maximum tide could:
Overtop nearly 58% of existing dikes
Inundate approximately 12,000 acres
Inundate critical infrastructure including utilities (municipal water lines/pump stations, wastewater lines/lift stations, gas lines, electrical transmission towers, and optical fiber lines) and transportation (Highway 101 and 255 and local roads/streets).
Loss of snowpack may reduce summer low flows for local rivers leading to increased stress on fish and other aquatic species.
Impacts to fisheries are possible due to shifts in ocean chemistry which lower pH, reducing oyster and clam productivity.
Sea level rise may make tidal marshland susceptible to more frequent, longer, and deeper flooding.
Higher temperatures and longer dry seasons would increase wildfire risk and impair water quality in local streams and lakes.
(DWR California Climate Science and Data for Water Resources Management, June 2015)
With the highest rate of sea level rise in California – 18.6 inches over the last century – and many populated low-lying areas, the Humboldt Bay region will have to adapt to the challenges of sea level rise sooner than other parts of the state. Highways, sewer treatment plants, contaminated sites, power plants and lines, and drinking water supplies all need to be adapted as we plan for he inevitable and potentially catastrophic changes brought as sea level rises.