Pacifica, California’s Natural Coastal Erosion and the Lust for Climate Catastrophes
Guest essay by Jim Steele
Director emeritus Sierra Nevada Field Campus, San Francisco State University
For 25 years I’ve lived in the beautiful town of Pacifica, California
situated about 15 miles south of San Francisco. It was a wonderful
place to raise a family. Its great expanse of green space is a delight
for an ecologist. My daily hikes vary from coastal bluffs to watch
feeding Humpback Whales or migrating Gray Whales, to inland mountain
trails with abundant deer, coyotes and bobcats. Oddly this past week I
received emails from friends around the country asking if I was “all
right”, thinking my little slice of heaven was falling into the sea. Not
to disrespect their concern, I had to belly laugh. The news of a few
houses, foolishly built on fragile land too near the sea bluffs’ edge,
were indeed falling into the ocean and were now providing great
photo-ops for news outlets around the world. See a
video here.
It is fascinating how such an isolated event covering 0.5% of the town
of Pacifica would suggest to friends that the whole town was endangered.
But it was more bizarre that this dot on the map could be
extrapolated into an icon of CO2 climate change. I could only laugh as
ridiculous CO2 alarmists who metamorphosed a local disaster, brought
about by ignorance of natural coastal changes, into a global warming
“crystal ball”.
NBC news reported
the Pacifica event as “a brief window into what the future holds as sea
levels rise from global warming, a sort of a crystal ball for climate
change.” The
SF Chronicle
suggested “increased global warming and rising sea levels due to
climate change would double the frequency of those severe weather events
across the Pacific basin.” The result would be “more occurrences of
devastating weather events and more frequent swings of opposite extremes
from one year to the next, with profound socio-economic consequences.”
Such apocryphal stories fueled a menagerie of bizarre blogging alarmists. I was recently
interviewed by James Corbett,
which incurred the wrath of a few internet snipers trying to denigrate
my scientific background. Not knowing I also live in Pacifica,
bd6951,
a skeptic‑bashing poster, linked to a video of threatened apartments in
Pacifica and commented, “What we are observing is run away climate
change/planetary warming. This is just a guess but, the architecture of
these apartment buildings suggest they are at least 20 years old. That
means the people who built these units had determined the site was
suitable for construction. They clearly were not thinking that an
increasingly warming Pacific Ocean would cause their buildings to crash
into the ocean 50 or more feet below. Oops. So I want to hear how the
climate change denier crowd is going to explain this phenomenon.”
But like so many other alarmists,
bd6951 blindly believes
every unusual event must be due to rising CO2. Because the media rarely
tries to educate the public about natural changes, paranoids like
bd6951
perceive every weather event as supporting evidence for their doomsday
beliefs, despite a mountain of evidence that it is all natural. Sadly
when you try to educate them about documented natural change, paranoids
feel you are “disarming them and exposing them to even greater dangers
of rising CO2. But anyone familiar with Pacifica’s history understands
this coastal erosion hotspot has nothing to do with global warming, and
everything to do with the local geology and the natural El Nino
oscillation.
So let’s put California’s eroding coastline into both a long term and
recent framework. About 72% of California’s coastline consists of steep
mountains slopes or raised marine terraces that are being relentlessly
chipped away by Pacific Ocean waves. However the geology of the coast is
complex due to varied depositional events, colliding plate tectonics
and earthquake faults. At one extreme are erosion-resistant
metamorphosed submarine basalts, greenstones, formed over 100 million
years ago during the age of dinosaurs, and often forming headlands that
defy the battering waves. Similarly the granites of the Monterrey
Peninsula endure with very little erosion. On the other extreme are
unconsolidated sandstones that were deposited during the past 12,000
years of the Holocene. Due to vastly different resistances to erosion,
California’s presents a majestically steep and undulating coastline. The
Pacifica locale has eroded more rapidly because the sea cliffs consist
mostly of weakly or moderately cemented marine sediments from the more
recent Pleistocene and Holocene. And because Pacifica has long been
known as a hot spot of coastal erosion, it has been studied for over 100
years. For a more detailed geology read a 2007 USGS report
Processes of coastal bluff erosion in weakly lithified sands, Pacifica, California, USA
. As always, before we can blame catastrophic CO2 climate change, we
must understand the local setting and the effects of natural change.
Since the end of the Last Glacial Maximum sea levels have risen about
120 meters. During the past 18,000 years most of California’s coast
retreated 10 to 20 kilometers eastward at rates of 50 to 150 centimeters
per year. The San Francisco/Pacifica region was much more susceptible
to erosion and retreated about 50 km. After the Holocene Optimum ended
about 5,000 years ago and sea level rise slowed, and California’s
current rate of coastal erosion decreased to about 10 to 30 cm/year.
Undoubtedly rising sea levels have driven coastal erosion. But based on
San Francisco Bay Area’s sea level change posted at
the PSMSL,
since the end of the Little Ice Age this region has undergone a steady
rise in sea level of less about 2 mm/year and counter-intuitively, the
rate of sea level rise has slowed the past few decades as seen in the
graph. Sea level rise varies most between El Nino and La Nina events.
Assuming a 150-year rate of local coastal erosion of 30 cm/year, any
structure built within 20 meters of the sea bluffs’ edge in 1950, was
doomed to fall into the ocean by 2015. But homebuyers that were new to
the region were typically naïve about the natural geology and climate.
Fortunately when I was shopping for Pacifica homes in 1982, my
background allowed me to recognize that developers had ignored all the
signs of natural climate change. They unwisely built homes too near the
cliffs’ edge to ensure a spectacular view, or they had built in the
flood plains and filled tidal marshes. Awareness of the power of El
Niño’s is critical. Sea cliffs crumble and flood plains flood during El
Nino events. Indeed during the 1982 El Nino, Pacifica’s Linda Mar
lowlands flooded as heavy precipitation filled the banks of San Pedro
Creek and high tides resisted the creek’s flow to the ocean. Inspecting
Linda Mar’s homes, we could still smell the dampness in every house
located in those lowlands. Along the bluffs of Esplanade Drive we
likewise saw a evidence of coastal retreat during the 1982 El Nino, but
not enough to undermine homes and apartments. That did not happen until
the El Nino of 1997/98. Wisely we bought our home further inland on a
solid ridge. As seen in the picture below from a
USGS report,
homes in the Esplanade area still had backyards until the 1997/98 El
Nino struck. Residents were well aware of the imminent threat as
revealed by the boulders, or riprap, placed at the base of the crumbling
cliffs to discourage erosion, but those remedies were no match for the
ensuing El Nino storm surge.
Unfortunately scientific measurements of coastal erosion did not
begin until the 1960s led by Scripps Institute of Oceanography. So early
developers had to guess how far back to set their homes from the
bluffs’ edge. Due to
recent research we now know that those cliffs had “retreated episodically at an
average rate of 0.5 to 0.6 meter (1.5 to 2 feet) per year over the past 146 years.”
But lacking geologic backgrounds and unaware of natural weather cycles,
developers’ ability to estimate a “safe distance” was hampered by the
episodic nature of coastal erosion that could lull people into believing
erosion was minimal.
Minimal erosion may happen for decades when La Ninas divert the storm
tracks northward, during which time naïve homebuyers and builders are
not alerted to inevitable future threats. Those mild periods are soon
followed by rapid losses during El Nino events. Thus ill informed in
1949, developers constructed several homes at the top of a 20-meter sea
cliff along Esplanade Drive in the city of Pacifica. During the heavy
winter storms of the 1997/1998 El Niño, 10 meters of local coastline
were rapidly eroded, eliminating the last vestiges of the backyards that
had survived the 1982 El Nino (see pre-1997 photograph below). In
1997/98, seven homes were undermined and three others threatened. All
ten homes were eventually condemned and demolished.
Nonetheless early developers should have been more cautious and
alerted by past catastrophes. Early entrepreneurs in California were
eager to develop its vast potential. The
Ocean Shore Railroad
was built, hoping to link San Francisco to Santa Cruz and entice more
immigration into the area, as well as to transport lumber and
agricultural products. Where the terrain was too daunting to go up and
over, they chiseled out ledges that circumscribed the coastal cliffs.
Scheduled to open in 1907, the 1906 San Francisco earthquake disrupted
those plans. Pacifica lies just south of the San Andreas Fault, and its
movement dropped a length of 4000+ feet of right-of-way along Pacifica’s
fragile sea cliffs into the sea along with all their railroad building
equipment. The surviving railroad ledges can still be seen today.
If you spend enough time walking along Pacifica’s beaches, you would
recognize an annual pattern of beach erosion. Heavy winter storms carry
the smaller grains of sand offshore restructuring a sandy beach into a
bed of rocky cobble. The gentler waves during the summer return the
sands to the beach and bury the cobble. The currents will also carry
some displaced sand down the coast, while those same currents also carry
sands from further upstream. When not enough sand is delivered to
replenish a beach, it undergoes rapid erosion. So in addition to natural
changes, the damming of rivers that halt the seaward supply of
sediments can starve a beach and promote erosion. Likewise when
naturally eroding cliffs are armored at their base by boulders, the lack
of local erosion can starve adjacent beaches of needed replenishing
sediments. Because of that possible impact on neighbors, the California
Coastal Commission now requires a permitting process before any seawall
can be built. Finally jetties that are built to protect harbors often
block the transport sand along the coast, starving beaches down stream
from the jetty and causing amplified erosion. In many locations,
governments dredge regions of sediment build-up, and dump those
sediments where beaches are now starving, such as being done by San
Francisco just north of Pacifica.
This region’s coastal erosion is episodic for well-understood
reasons. When a cliff face collapses it leaves a pile of rubble at the
cliff’s base, sometimes called the “toe”, which raises the beach and
acts to naturally buffer the cliff face from further erosion. After
several years, waves and currents carry the buffering toe away, and
eventually exposes the cliff to another “bite” from the ocean.
Furthermore the Pacific Decadal Oscillation is expressed as a 20 to
30 year negative phase with more frequent La Nina’s alternating with a
positive phase with more frequent El Nino’s. The relatively stationary
high-pressure systems prominent during La Nina’s, forces storm tracks to
the north of California. Fewer storms mean less coastal erosion, but
also result in more California droughts. The current return of El Nino
now allows storm tracks to attack the California coast. Snow is
currently above average in the Sierra Nevada and reservoirs are filling,
but simultaneously coastlines are more heavily eroded.
In addition, the effect of higher rates of precipitation associated
with El Nino also cause greater slippage between geologic layers that
differ in their ability to handle subsurface water flows. Heavier
precipitation caused episodic collapses of coastal Highway 1 at Devil’s
Side at the south end of Pacifica. A tunnel was just built to re-route
the highway away from that geologically unstable area.
For millennia El Nino cycles have caused these natural extreme swings
that alternate between droughts and floods and episodic coastal
erosion. Changing your carbon footprint will never stop the process. But
knowledge of these natural processes will keep people out of harms way.
One of the greatest sins of the politics of the climate wars is that
people are not being educated about natural climate change. They are not
being taught how to be wary of natural danger zones. Instead every
flood and every drought, every heat wave or snowstorm is now being hyped
as a function of global warming. After every catastrophic natural
weather event, yellow journalists like the Washington Post’s Chris
Mooney or APs Seth Bornstein, seek out CO2 alarmist scientists like
Kevin Trenberth or Michael Mann, to make totally unsubstantiated
pronouncements that the event was 50% or so due to global warming. After
centuries of scientific progress, Trenberth and his ilk have devolved
climate science to the pre-Copernican days so that humans are once again
at the center of the universe, and our carbon sins are responsible for
every problem caused by an ever-changing natural world.
You can recognize those misleading journalists and scientists who are
either totally ignorant of natural climate change, or who are
politically wedded to a belief in catastrophic CO2 warming, when they
falsely argue, as NBC news did, that “frequent swings of opposite
extremes” are due to global warming. El Nino’s naturally bring these
extremes every 3 to 7 years, as well as the 20 to 30 years swings of the
Pacific Decadal Oscillation. These swings have occurred for centuries
and millennia! The same storms that bring much needed rains will also
batter the coast and increase episodic erosion. But by ignoring natural
change, climate fear mongers delude the public into believing La
Nina-caused droughts of the past few years were due to CO2 warming. And
now as El Nino returns the rains to California, those same climate fear
mongers want us to believe CO2 warming is causing an abrupt swing to
heavy rains and coastal erosion. One needs only look at the historical
records to find Pacifica’s coastal erosion was much greater around the
1900’s, and that El Ninos have caused natural extreme swings for
millennia.
Honest science, useful science, must educate people about our natural
hazards and natural climate oscillations; so that people do not build
too close to fragile cliff edges or build in the middle of a flood
plain. It is not just the coast of California that is eroding. The
politicization of climate change is eroding the very integrity of
environmental sciences. Reducing your carbon footprint will never save
foolishly placed buildings in Pacifica or stop the extreme swings in
weather induced by El Nino’s and La Nina’s. It was the end of the Ice
Age that initiated dramatic coastal erosion and only a return to those
frozen years will stop it. Pacifica’ eroding bluffs are simply evidence
that most of California has still not reached an equilibrium with the
changes that began 18,000 years ago. Pacifica is truly an icon of
natural climate change.
But the ranks of climate alarmists are filled with legions of
scientific ignoranti who blindly see such coastal erosion as another
“proof” of impending CO2-caused climate hell. This group lusts for
climate catastrophes to prove they are not blindly paranoid. Other
self-loathing CO2 alarmists simply lust for climate catastrophes that
will deal humans their final “come-uppance.” So they too lust for
climate catastrophes. Only a solid of understanding of natural climate
change can prevent this climate insanity and pave the way to truly
scientifically based adaptive measures.
From Freedom Outpost:
Coccolithophore. 
