Sea Level Rise

The Humboldt Bay area is experiencing the fastest rate of relative sea level rise on the West Coast. That's because tectonic activity is causing the ground beneath the bay to sink at the same rate that the ocean is rising. According to the California Ocean Protection Council's 2024 Science & Policy Update, sea level in the Humboldt Bay area is expected to rise approximately 1.5-2 feet above 2000 levels by 2060 and 3.9-5.5 feet by 2100.

The primary impacts from sea level rise are increases in flooding, erosion, and rising groundwater. Sea level rise will expand areas vulnerable to flooding during major storms, as well as in the rare but catastrophic event of a major tsunami. The term 100-year flood is used as a standard for planning, insurance, and environmental analysis. But these extreme storms are happening with increasing frequency, in part due to rising seas. Sea level rise will cause more frequent—and more damaging—floods to those already at risk and will increase the size of the coastal floodplain, placing new areas at risk to flooding. To view sea level rise scenarios for the Humboldt Bay area, visit NOAA's 2022 Sea Level Rise Viewer and go to the local scenario for the North Spit.

NEW! Now you check out our interactive map of two sea level rise scenarios for the Humboldt Bay Area! Featured are scenarios showing 1- and 2-meters above Year 2000 water levels. For many years, these have been static maps with no simple way for the public to examine points of interest. Now, people wondering if their neighborhood is at risk can zoom in on locations and see street names, etc.

California faces more serious risk of sea level rise than other areas

6/22/12

As the world continues to warm from climate change, most of California -- including San Francisco Bay -- will see a greater rise in sea level than other parts of the planet, according to a prominent national study released Friday.

The report, from the National Academy of Sciences, found that the impacts of melting ice and warming, expanding oceans will hit California harder because most of the state's coastline is slowly sinking due to geological forces.

Ocean levels south of Humboldt County will rise up to 1 foot in the next 20 years, 2 feet by 2050, and up to 5 feet by 2100, the study showed.

Rising sea levels around Humboldt Bay

  Aldaron Laird, who walked or kayaked all 102 miles of Humboldt Bay’s shoreline and its sloughs as part of his study, “Humboldt Bay Shoreline Inventory, Mapping and Sea Level Rise Assessment,” was the featured speaker on May 30 at the Arcata Marsh Interpretive Center.

Laird is an environmental planner who specializes in getting permits for wetland enhancement projects and doing historical studies of rivers and tidal waters. He produced the Humboldt Bay Historical Atlas in 2007.  

This year, Laird is completing work for a California Coastal Conservancy grant to inventory the bay’s shoreline and “ground truth” GIS data on the shoreline’s attributes — part of a statewide effort to map areas that will be affected by sea level rise.   During his tour of the bay's shoreline, Laird discovered that acres of diked farmland are currently ill-equipped to hold back the rising sea. The last native salt marsh ecosystems are also at risk of being drowned out by sea level rise.   Laird’s presentation will include some of his 14,000 photographs taken during the project.

To watch online, click HERE. Thanks to Access Humboldt!

For more info, see "Aldaron's Walkabout" in January's North Coast Journal.

Rising Sea Levels Seen as Threat to Coastal U.S.

3/13/12

About 3.7 million Americans live within a few feet of high tide and risk being hit by more frequent coastal flooding in coming decades because of the sea level rise caused by global warming, according to new research.

If the pace of the rise accelerates as much as expected, researchers found, coastal flooding at levels that were once exceedingly rare could become an every-few-years occurrence by the middle of this century.

A Slow Motion Flood: Rapid Sea Level Change on the North Coast

2/15/12

Rapid sea level rise in the next 100 years could affect more than coastal residents may think.

The rise could change the environment of the Arcata Marsh, create prime salmon habitat or affect property values, said local scientist Michael Furniss.

Rough Waters for Sea Level Rise Planning

7/29/11

What do Bay Area airports and some big Silicon Valley companies have in common? They sit right on the edge of San Francisco Bay, where sea level rise is expected to have a big impact by the end of the century.

That may seem far in the future, but state agencies are preparing for climate change now by writing new rules for construction along the bay’s shoreline. As you can imagine, developers and environmentalists aren’t exactly seeing eye to eye.

California faces more serious risk of sea level rise than other areas

Rising sea levels around Humboldt Bay

Rising Sea Levels Seen as Threat to Coastal U.S.

A Slow Motion Flood: Rapid Sea Level Change on the North Coast

Rough Waters for Sea Level Rise Planning

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