Sea Level Rise and Possible Increased Storms in Laguna Beach

Sea Level Rise and Possible Increased Storms in Laguna Beach

Laguna Beach’s attractions have been the beaches, the canyon, the cliffs, the foliage, the artists who have settled here, and the community spirit and involvement.

Our climate effects evaluation does not include a full evaluation of challenges of protecting the ocean environment. But in keeping our blue ocean blue, we must note the impending challenges of having federal intrusion with new offshore oil drilling leases. We also must mention the relaxing of rules protecting off-shore drilling from accidents.  So far, there are no direct attacks on our Marine Protection Areas, but offshore drilling is itself an attack. We have to make our views known to our Representative for the 48th District, which stretches along the coast, Rep. Dana Rohrabacher. Our city and community must oppose such efforts of the federal Administration, and support California’s, Oregon’s, and Washington state’s resistance to them.  Since the oil will go to California refineries and gas stations, we have the opportunity to Boycott any companies that participate in such oil drilling, refining, or marketing.

Looking out to our ocean, far far away, on shores where coral reefs have existed since ancient times, the reefs are rapidly disappearing due to ocean warming.  They are the nurseries of a quarter of ocean species.  Shelfish, mollusks, and plankton that sequester carbon are disappearing due to ocean acidification with dissolved CO2.  Our local kelp plants absorb CO2 and encompass in them a slightly less acidic environment to nurture mollusks.  This year’s warming and calming La Niña has added to our shores the threat of sting rays.  As an ocean enhanced and appreciating community, we are highly motivated to combat climate change and save the entire ocean ecosystem.

The threat of sea level rise is one of the slowest creeping phenomena imaginable. With Laguna’s cliffs, their fortifications, and raised Coast Highway, we are one of the least vulnerable locations compared to our neighbors like Huntington Beach and Balboa Island, or San Francisco Bay and the Delta River region.  The projected mean sea level rise by 2100 in the middle projection is 3.3 feet. The Coast Highway in downtown Laguna would be flooded when sea level rises to 7 feet. If there is faster Greenland and Antarctic melting, the Pacific coast could rise another 2-3 feet. Protecting downtown Laguna Beach might eventually require a beachside sea wall on Main Beach, which could be installed in a short time.  By 2100, however, the sea level rise may cause cliffs to erode twice as fast under wave action.  Armoring the walls won’t allow sand to be replenished by erosion, and will be washed away, so sand will have to be brought in to protect the walls.

Yet there are 10,000 people in Orange County or the 48th Congressional district living less than three feet above high tide level. 6,000 are in Newport Beach, 3,100 in Huntington Beach, and 400 in Sunset Beach. In the 47th Congressional District covering Long Beach, there are 6,000 people living below 3 feet. Around the SF Bay are 107,000 people living below 3 feet above mean sea level. In the Sacramento-San Joaquin River Delta are 78,000 people living less than one foot above high tide, but protected by levees that will be overridden for a three foot rise. We are all connected to these people by family, friends, employment, economics, and providing our food, water, and goods. Protecting the rest of California must remain a main motivation for a long term and significant reduction in our own greenhouse gas production.  An immediate main threat to California is that droughts lead to very destructive wildfires, driven by desert winds.  This is also a threat from Laguna Canyon.

The true threat, illustrated in the vast Houston flood of last year, is for instantaneous and severe rainfall in a Pineapple Express rainstorm. This is an atmospheric River of moisture originating in the Eastern tropical Pacific. About half of our rainfall comes from such storms, in about four or five such events a year. Laguna has already seen landslides from such events as in Bluebird Canyon, and often flooding down the Canyon. Over the remainder of the century, we expect more such storms, and with greater rainfall. With these may come storm surges, and wind whipped waves on top of that. Adding this to end-of-century sea level rise can damage Coast Highway and a fair part of downtown Laguna. The most severe prediction of a six foot sea level rise plus two feet of storm surge, and with an additional two feet of waves, for a ten foot above mean sea level inundation, would flood downtown up to Beach street.

The city must keep monitoring the improving sea level rise and storm modeling predictions, so that it can respond to them in a timely manner. Completing an effective Canyon drainage system through the Coast Highway should be a top priority. Still to be evaluated is if a large sea level rise can eventually seep under the Coast highway, and into downtown cellars.  This might require pumps to keep our ocean outlets from backing up into the city at high tides.  Rebuilding over the years must consider this and sea level rise. The eventual threats are real, and many cities and areas have been in denial and severely damaged by unexpected and rare 100 and 500 year floods.

In my Flickr account, I have an album at the King low tide, revealing the vast underwater sealife lying just off our shore of Heisler Park.

 

About Dennis SILVERMAN

I am a retired Professor of Physics and Astronomy at U C Irvine. For a decade I have been active in learning about energy and the environment, and in lecturing and attending classes at the Osher Lifelong Learning Institute (OLLI) at UC Irvine.
This entry was posted in Climate Change, Climate Science, Coastal Flooding, Dana Rohrabacher CA 48th, Greenhouse Gas Emissions, Laguna Beach Energy Savings, Laguna Beach Flood Levels, Offshore Oil Drilling, Sea Level Rise. Bookmark the permalink.

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