Rising sea destroys homes, erases beaches in California

Rising sea destroys homes, erases beaches in California reuters.com

41 points•geox•5 days ago•34 comments•

#california #sea #destroys #homes #erases #rising #beaches #rising sea

34 comments

Coastal erosion =/= sea level rise.

This is textbook expected behavior on a high energy deep water coast (eg cliffs, not mangroves)

Ya, I don't want to minimize the problem of sea levels rising, but the recent storms had massive swells (I believe partially because of the El Nino year). The sand on most of these beaches is not natural, it's pumped up to the shore to encourage tourism. It is normal for it to wash away during big swell, and not necessarily an indication of the sea level rising.

You could argue that the extreme El Nino this year is due to global warming, which is obviously related, but it's not quite the same as just rising sea levels.

Animats5 days ago

It's annoying for coastal areas, and a problem for beach houses, but California isn't really that vulnerable to rising sea levels. The Pacific Coast is mountainous and the ground slopes upward in short distances.

Here's the US topo map.[1] Look at vulnerable spots, such as Malibu and Oceanside. Three blocks inland you're 20 feet above sea level. Almost all problems are on the ocean side of the Pacific Coast Highway, which was a marginal place to build anyway.

Cliff edge erosion is an ongoing problem. That's why CALTRANS gave up on Devil's Slide as a road route and built the Tom Lantos Tunnels further inland. Small changes in sea level don't affect hundred-foot cliffs that much, though.

The places that really suffer from rising sea level are river deltas, sitting on deposited sand just barely above sea level. In the US, New Orleans has the worst problem. New York City has problems, and they're building coast defenses against storms. China's coastal cities are mostly on river deltas with really flat terrain. That's why China has to build ports way off shore, reached by miles of bridges, to get to deep water.

[1] https://en-us.topographic-map.com/map-9t5k57/Venice-Beach/?c...

bix65 days ago

CA already floods at high tide so I think another 10 ft is really gonna mess stuff up. There are so many rivers that empty at sea level and a lot of roads that cross over low points that will need reworking.

WillAdams5 days ago

I just dodged being stuck on the Outer Banks or evacuating for a hurricane which has now closed Hwy 12 based on which week the family agreed on for the annual beach vacation:

https://www.outerbanksnews.org/post/n-c-highway-12-damaged-c...

(and they have an on-going beach replenishment effort as well)

gboss5 days ago

Isn’t the Bay Area quite vulnerable? I’m thinking they’re going to have to build a dam with locks in front of the golden gate

Animats5 days ago

No way. The Golden Gate is really deep.

The Bay Bridge channel is so shallow it has to be dredged. There was a 1946 plan to fill it in.[1] There were Corps of Engineers plans for a lot of filling, but they didn't go that far. I have a copy of their 1960-2020 plan for the Bay Area.[2] Their vision was to make the SF bay area a major industrial city, building on the facilities built for WWII. Aluminum smelter in Sausalito. Steel mills at Tiberon. Five freeways up the Peninsula (101, 280, 35, 1, and one on stilts in the bay.) Another Bay Bridge. Maybe a SF-Alcatraz-Angel Island-Tiberon link. It would have been like Pittsburgh.

[1] https://www.sfgate.com/local/article/second-bay-bridge-plans...

[2] https://archive.org/details/futuredevelopmen00unit

kzrdude5 days ago

The topographic map says, the Bay Area is just around the first bay, there's a whole second bay opening up behind it (Sacramento area valley) which could flood with enough sea level rise.

comrade12345 days ago

The problem with that is that there are rivers and streams emptying into the bay. All of that water has to make it to the sea somehow.

nostrademons5 days ago

The Bay Area is one big river delta, going inland to Sacramento.

It's not the Pacific coast communities you have to worry about like Half Moon Bay or Santa Cruz. They have a beach, and then cliffs, and then the actual city is like 50-100 feet above sea level.

It's the bayside communities. Foster City. Redwood Shore. The Embarcadero. SFO. Port of Oakland. Highway 101.

All of these are pretty critical parts of Bay Area infrastructure, and gone with as little as a 1.6' sea level rise + 20yr storm.

https://www.kqed.org/science/1973624/maps-see-which-bay-area...

skybrian5 days ago

Foster City has a pretty hefty levee [1]. Palo Alto is building a "horizontal levee" [2]. Looks like Redwood Shores will be raising theirs [3].

This work has to be done for good reason, but looks like they're on it?

[1] https://fostercitylevee.org/ [2] https://www.sfchronicle.com/climate/article/palo-alto-sea-le... [3] https://www.smdailyjournal.com/news/local/new-200m-levee-upg...

skyberrys5 days ago

This is a pretty cool map. I'm at 20' above sea level. That should be good enough right?

readthenotes15 days ago

Im pretty sure _don't look up_ was supposed to be a scathing indictment of climate change deniers, but it makes me wonder how many people living in low low-lying areas of the seacoast claim to believe that climate change is real and happening and vote for everyone else to change their lives but ignore the water lapping at their doorstep

WillowWithAWand5 days ago

[Insert HbomberguyShoutingAtBenShapiro.gif here]

hooli_gan5 days ago

https://www.youtube.com/watch?v=0-w-pdqwiBw

netbioserror5 days ago

I would think the dominating factors in Oregon and California are their uplifted soft geologies. The orogenies that lifted the West have resulted in an elevated, cliff-bounded sandy coastline along the Pacific that has been aggressively eroding for a lot longer than humans have been there.

metalman5 days ago

right, except that humans have fixed the high tide lines over whole geolographical areas and done massive work to redirect almost all of the rivers and streams to agriculture, industry and domestic uses, and stopping most of the sand from reaching the ocean, plus sand mining for building is so extensive that there now shortages, meaning that the main surface sources are gone. those fixed high tide lines are also the collateral for trillions of dollars in loans and investments, and given the tripple wammy described in the article, things could get out of hand in a whole new way.

Read the full thread on Hacker News →

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