Bye-Bye Beaches: How Parts of SoCal's Iconic Coast Could Disappear in Our Lifetime
By Jacob Margolis
The stretch of coast from Santa Monica to Malibu is iconic and quintessentially Californian. It's also ridiculously beautiful — and it's clear, based on the latest science, it could be unrecognizable by the end of the century.
As the planet warms, sea levels will continue to rise, threatening some of our most beloved stretches of coastline.
I was lucky enough to spend a lot of time on those beaches. Raised in the San Fernando Valley, I used to head over the hill in my friend's baby blue VW bus, or my mom's minivan, to surf Topanga or Malibu on my 9'8 Kennedy longboard. It was and still is an amazing escape from the traffic, heat and urban sprawl of the Valley.
I wanted to know exactly what climate change could mean for our beach-going experience through the end of the century, so I reached out to scientists and stakeholders to find out what they know.
Here are the challenges — and some solutions.
Seas Will Rise
First, some context.
A few feet of sea level rise might not sound very alarming, but every vertical foot could mean roughly 20 feet farther that the ocean encroaches inland (depending on a lot of factors, like the slope of the coastline), according to Patrick Barnard, a research scientist at the US Geological Survey.
The state's 2018 sea level rise guidance laid out different scenarios based on how much we curb our greenhouse gas emissions.
- Low emissions: 66% chance of between 0.9 and 2.3 feet of rise in Santa Monica by 2100, and similar rise in other parts of Southern California.
- High emissions: 66% chance of between 1.5 and 3.3 feet of rise, with a .5% probability we'll see 6.8 feet.
As a precaution, the report recommends that state officials anticipate 10 feet of rise when building crucial infrastructure along the coast.
Keep in mind some researchers think we've been underestimating just how bad things could get.
Beaches Will Disappear
According to a paper co-authored by Barnard, SoCal could lose between 31% - 67% of its beaches by 2100.
And areas like Malibu could be threatened in the coming decades.
"I mean these are very, very narrow beaches. They're already having lots of issues, and just a bit of sea level rise and they're going to be completely gone," said Barnard, adding that Malibu could see a major loss of its beaches in the coming decades.
Our coastline is always changing, but as sea levels rise and intense storm surges (potentially) become more common, there's conflict between natural processes and the parts of our coast we want to save.
"If we didn't have anything built on the coast, the beaches in the coastal zone are incredibly dynamic and built to change. When sea level comes up, the beach moves in. When sea level goes out ... the beach moves out with it," said Kiki Patsch, who studies sediment dynamics at Cal State Channel Islands.
"But when sea level rises and we draw a line in the sand and say, 'This is the beach and these are my homes,' we have a problem," she said.
When water encroaches and beaches have nowhere to go, because we decide to protect infrastructure and homes, we're likely going to lose those beaches.Beaches like Santa Monica that have been widened with massive amounts of sediment could hold up with regular additions of sand, at least for a period of time.
Here's a visualization of what rising sea levels could theoretically look like from the pier:
Caltrans just released its vulnerability assessments for our region, and they're particularly bleak for our coast. There's not much area between the ocean and the hills in many spots. Really, much of it's just homes and critical infrastructure, like PCH. Which means that in some places we're going to have to decide between one or the other.
"There can be situations where if we're using shoreline protection to protect private residential development, that might be coming at the expense of a public beach area. And that's going to be a huge environmental justice issue," said Madeline Cavaleri, statewide planning manager for the California Coastal Commission. "We don't know how this is going to play out."
Surfing Could Take a (Duck) Dive
Surf spots are complicated.
I talked to Dan Reineman, a professor at Cal State Channel Islands who's studied the impact of sea level rise on waves.
He said that at three feet, Malibu's waves could get mushy. Surfers already experience that at high tide. With sea level rise it would be like it's high tide all the time.
That said, it's more complicated than just plunking down additional water on top of a break. How we manage our coasts and sediment flow will all impact what we experience on shore.
"Whether you are armoring the sea cliffs or damming the rivers, that'll have ramifications all of the way down the coast, because that is where the sand is coming from," said Patsch.
That could mean that if we decide to stick sea walls and big piles of rocks up and down our coast to protect what's there, surf spots could suffer, too.
That could, "pull the sand offshore and downshore, so it'll get deeper offshore. Waves break because they start to interact with the bottom, so when it's deeper you lose your surf break," she said.
Derek Grimes, a Ph.D. student in physical oceanography at Scripps, noted that while the transport of sediment could negatively impact Malibu's beaches, we don't know how it could impact other breaks up and down the coast. It's possible that new, sought-after spots will pop up.
Grimes told me he's seen that happen off the coast of North Carolina when the bottom of channels are dredged for ships.
What We Do Matters
The good news is that everything we love about our coast is not going to disappear overnight. And we'll have the opportunity to decide how we want to manage things going forward.
- We can continue to dump sand and "nourish" beaches, though sand is an expensive and finite resource that can be wiped away easily by storms.
- Places like Santa Monica and Cardiff Beach are experimenting with living dunes.
- We can move homes and Highway 1 - and maybe even turn the latter into, say, hiking areas, like they did in Pacifica.
- And some people want to install armoring up and down our entire coast, which could run into big problems with California law. Some homeowners in places like Broad Beach in Malibu figured out a workaround and did it on their own.
Some sea level rise is already baked in, but at a very high level, curbing our emissions worldwide would certainly help.
This story originally appeared in LAist. It is republished here as part of EcoWatch's partnership with Covering Climate Now, a global collaboration of more than 250 news outlets to strengthen coverage of the climate story.
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Kevin T. Smiley
When hurricanes and other extreme storms unleash downpours like Tropical Storm Beta has been doing in the South, the floodwater doesn't always stay within the government's flood risk zones.
New research suggests that nearly twice as many properties are at risk from a 100-year flood today than the Federal Emergency Management Agency's flood maps indicate.
Flooding Outside the Zones<p>About <a href="https://furmancenter.org/files/Floodplain_PopulationBrief_12DEC2017.pdf" target="_blank">15 million</a> Americans live in FEMA's current 100-year flood zones. The designation warns them that their properties face a 1% risk of flooding in any given year. They must obtain flood insurance if they want a federally ensured loan – insurance that helps them recover from flooding.</p><p>In Greater Houston, however, <a href="https://doi.org/10.1111/j.1539-6924.2012.01840.x" target="_blank">47% of claims</a> made to FEMA across three decades before Hurricane Harvey were outside of the 100-year flood zones. Harris County, recognizing that FEMA flood maps don't capture the full risk, now <a href="https://www.hcfcd.org/floodinsurance" target="_blank" rel="noopener noreferrer">recommends that every household</a> in Houston and the rest of the county have flood insurance.</p><p>New risk models point to a similar conclusion: Flood risk in these areas outstrips expectations in the current FEMA flood maps.</p><p>One of those models, from the <a href="https://firststreet.org/flood-lab/research/2020-national-flood-risk-assessment-highlights/" target="_blank">First Street Foundation</a>, estimates that the number of properties at risk in a 100-year storm is 1.7 times higher than the FEMA maps suggest. Other <a href="https://doi.org/10.1088/1748-9326/aaac65" target="_blank" rel="noopener noreferrer">researchers</a> find an even higher margin, with 2.6 to 3.1 times more people exposed to serious flooding in a 100-year storm than FEMA estimates.</p>
What FEMA’s Flood Maps Miss<p>Understanding why areas outside the 100-year flood zones are flooding more often than the FEMA maps suggest involves larger social and environmental issues. Three reasons stand out.</p><p>First, some places rely on relatively old FEMA maps that don't account for recent urbanization.</p><p>Urbanization matters because impervious surfaces – think pavement and buildings – are not effective sponges like natural landscapes can be. Moreover, the process for updating floodplain maps is locally variable and can take years to complete. Famously, New York City was updating its maps when Hurricane Sandy hit in 2012 but hadn't finished, meaning flood maps in effect <a href="https://projects.propublica.org/nyc-flood/" target="_blank">were from 1983</a>. FEMA is required to assess whether updates are needed every five years, but the <a href="https://www.fema.gov/cis/nation.html" target="_blank" rel="noopener noreferrer">majority of maps</a> <a href="https://www.oig.dhs.gov/sites/default/files/assets/2017/OIG-17-110-Sep17.pdf" target="_blank" rel="noopener noreferrer">are older</a>.</p><p>Second, binary thinking can lead people to an underaccounting of risk, and that can mean communities fail to take steps that could protect a neighborhood from flooding. The logic goes: if I'm not in the 100-year floodplain, then I'm not at risk. Risk perception <a href="https://doi.org/10.1088/1748-9326/ab195a" target="_blank" rel="noopener noreferrer">research</a> backs this up. FEMA-delineated flood zones are the major factor shaping flood mitigation behaviors.</p><p>Third, the era of climate change scuttles conventional assumptions.</p><p>As the planet warms, extreme storms are becoming <a href="https://nca2018.globalchange.gov/" target="_blank">more common and severe</a>. If greenhouse gas emissions continue to increase at a high rate, computer models suggest that the chances of a severe storm dropping 20 inches of rain on Texas in any given year will increase from about 1% at the end of the last century to 18% at the end of this one, a chance of <a href="https://doi.org/10.1073/pnas.1716222114" target="_blank" rel="noopener noreferrer">once every 5.5 years</a>. So far, <a href="https://www.rstreet.org/wp-content/uploads/2020/02/195.pdf" target="_blank" rel="noopener noreferrer">FEMA hasn't taken into account the impact climate change is having</a> on extreme weather and sea level rise.</p>
Racial Disparities in Flooding Outside the Zones<p>So, who is at risk?</p><p>Years of research and evidence from storms have highlighted social inequalities in areas with a high risk of flooding. But most local governments have less understanding of the social and demographic composition of communities that experience flood impacts outside of flood zones.</p><p>In analyzing the damage from Hurricane Harvey in the Houston area, I found that <a href="https://doi.org/10.1088/1748-9326/aba0fe" target="_blank">Black and Hispanic residents disproportionately experienced flooding</a> in areas beyond FEMA's 100-year flood zones.</p><p>With the majority of flooding from Hurricane Harvey occurring outside of 100-year flood zones, this meant that the overall impact of Harvey was racially unequal too.</p><p>Research into where flooding occurs in Baltimore, Chicago and Phoenix points to some of the potential causes. <a href="https://www.nap.edu/read/25381/chapter/4#16" target="_blank" rel="noopener noreferrer">In Baltimore and Chicago</a>, for example, aging storm and sewer infrastructure, poor construction and insufficient efforts to mitigate flooding are part of the flooding problem in some predominantly Black neighborhoods.</p>
What Can Be Done About It<p>Better accounting for those three reasons could substantively improve risk assessments and help cities prioritize infrastructure improvements and flood mitigation projects in these at-risk neighborhoods.</p><p>For example, First Street Foundation's risk maps account for <a href="https://firststreet.org/flood-lab/research/flood-model-methodology_overview/" target="_blank">climate change</a> and present <a href="https://floodfactor.com/" target="_blank" rel="noopener noreferrer">ratings</a> on a scale from 1 to 10. FEMA, which works with communities to update flood maps, is <a href="https://www.fema.gov/media-library-data/1521054297905-ca85d066dddb84c975b165db653c9049/TMAC_2017_Annual_Report_Final508(v8)_03-12-2018.pdf" target="_blank" rel="noopener noreferrer">exploring rating systems</a>. And the National Academies of Sciences, Engineering and Medicine recently <a href="https://www.nationalacademies.org/news/2019/03/new-report-calls-for-different-approaches-to-predict-and-understand-urban-flooding" target="_blank" rel="noopener noreferrer">called for a new generation of flood maps</a> that takes climate change into account.</p><p>Including recent urbanization in those assessments will matter too, especially in fast-growing cities like Houston, where <a href="https://authors.elsevier.com/a/1boBRyDvMFW6W" target="_blank" rel="noopener noreferrer">386 new square miles</a> of impervious surfaces were created in the last 20 years. That's greater than the land area of New York City. New construction in one area can also <a href="https://scalawagmagazine.org/2018/01/city-in-a-swamp-as-houston-booms-its-flood-problems-are-only-getting-worse/" target="_blank" rel="noopener noreferrer">impact older neighborhoods downhill</a> during a flood, as some Houston communities discovered in Hurricane Harvey.</p><p>Improving risk assessments is needed not just to better prepare communities for major flood events, but also to prevent racial inequalities – in housing and beyond – from <a href="https://www.npr.org/2019/03/05/688786177/how-federal-disaster-money-favors-the-rich" target="_blank" rel="noopener noreferrer">growing</a> after the unequal impacts of disasters.</p>
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