The Kevin Trenberth Effect: Pulling Science Back to the Dark Ages - Part 1 Droughts and Heat waves

In my essay on the natural causes of Pacifica’s Coastal Erosion, I reported on how California’s coast has still not reached an equilibrium with sea levels that rose at the end of the last ice age. I also suggested the media and a few scientists give the public a false impression that all natural weather phenomenon and coastal erosion have been worsened by CO2-driven climate change. Pointing to a few leading perpetrators I wrote, “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.” Such a strong statement deserves further elaboration. Although a highly intelligent scientist, to support his obsessive claims that CO2-caused climate change has worsened every extreme event, Trenberth has been tragically undermining the very foundations of scientific inquiry by 1) reversing the proper null hypothesis, 2) promoting methods that can not be falsified, 3) promoting fallacious arguments only by authority, and 4) stifling any debate that promotes alternative explanations.

Dr. Trenberth, via his well-groomed media conduits, preaches to the public that every extreme event - flood or drought, heat wave or snowstorm - is worsened by rising CO2. To fully appreciate the pitfalls of his “warmer and wetter” meme, you need to look no further than Trenberth’s pronouncements regards the devastating Moore, Oklahoma tornado. Although Trenberth admits, “climate change from human influences is difficult to perceive and detect because natural weather-related variability is large”, in a Scientific American interview, arguing only from authority he cavalierly attributed CO2 climate change to a “5 to 10 percent effect in terms of the instability and subsequent rainfall, but it translates into up to a 33 percent effect in terms of damage.” But in contrast to Trenberth’s “warmer and wetter world” assertions, there was no warming contribution. Maximum temperatures in Oklahoma had been cooler since the 1940s.

Clearly Trenberth’s simplistic “warmer and wetter” world assertion cannot be applied willy-nilly to every region. Climate change is not globally homogenous. It is regionally variable and the global average temperature is a chimera of that regional variability. Furthermore his claim of a “wetter world” is a hypothetical argument not supported by evidence. As seen in the graph below from the peer-reviewed paper Weather And Climate Analyses Using Improved Global Water Vapor Observations, there is little evidence of a steady increase in water vapor paralleling rising CO2. Even Trenberth’s own studies have concluded, “Total Precipitable Water vapor [TPW] variability for 1988–2001 was dominated by the evolution of ENSO [El Ninos].” The El Nino effect is evidenced by peak water vapor coinciding with the 1998 El Nino. Since 1998, the atmosphere has been arguably drier, contradicting his CO2 driven wetter world hypothesis. Despite a multitude of contradictions, to garner support for his theories Trenberth insists on reframing the scientific method by reversing the null hypothesis. Instead of determining if CO2 had an effect on extreme weather beyond what natural variability predicts, Trenberth wants scientists and the public to blindly assume, “All weather events are affected by climate change because the environment in which they occur is warmer and moister than it used to be.”

Trend in Total Precipitable Water (TPW) Contradicts Trenbert's Assertions

In contrast to simply making the “Trenberth assumptions”, climate scientists use two main strategies to extract any possible CO2 effect. First based on physics, the consensus believes early changes in CO2 concentration exerted no significant climate impact, and extreme events happening before 1950 were due to natural variability. Thus historical analyses compare extreme events before and after 1950 to determine how they differ. But Trenberth has been maneuvering to make such CO2 attribution studies non-falsifiable by stripping recent extreme weather events from that historical framework. In the Washington Post, Chris Mooney pushes Trenberth’s “new normal” quoting,

“All storms, without exception, are different. Even if most of them look just like the ones we used to have, they are not the same.”

Trenberth’s “new normal” side steps historical scientific analyses. One would think a good investigative reporter would question Trenberth’s undermining of that scientific methodology, but Mooney is not a scientist. Ironically Mooney’s claim to fame was a book “The Republican War On Science”, about which Washington Post’s Keay Davidson wrote, "Mooney is like a judge who interprets a law one way to convict his enemies and another way to acquit his friends.” Evidently that is just the kind of journalist Trenberth and the Washington Post wanted. Mooney left Mother Jones and was hired by Washington Post to write columns on climate change and serves as one of Trenberth’s media conduits. (Btw: the Real Science website is a great place to view headlines from the past illustrating great similarities between past and present extreme weather events.)

The second strategy relies on models that compare “the probability of an observed weather event in the real world with that of the ‘same’ event in a hypothetical world without global warming.”  But this approach incorrectly assumes the natural variability is well modeled. Often the model’s “world without global warming” is assumed to be stationary but with a lot of “noise”. But that tactic generates false probabilities because our natural climate is not stationary but oscillating. In 2012 climate experts met at Oxford University to discuss such attribution studies and the highlights were reported in Nature. Many experts suggested that due to “the current state of modeling any attribution would be unreliable, and perhaps impossible…One critic argued that, given the insufficient observational data and the coarse and mathematically far-from-perfect climate models used to generate attribution claims, they [attribution claims] are unjustifiably speculative, basically unverifiable and better not made at all. And even if event attribution were reliable, another speaker added, the notion that it is useful for any section of society is unproven.”

(Such concerns raise another question: if attributing a CO2 effect on any event like a heat wave or drought is nearly impossible, how reliable is any attribution of a global average temperature if those same extreme heat waves and droughts skew the global average?)

Color me an old-fashioned scientist, but our best practices demand we correctly establish the boundaries of natural climate change before we can ever assume rising CO2 has worsened weather events. But Trenberth and his ilk insist on reversing the null hypothesis. Instead of asking if a weather event exceeded natural variability, Trenberth insists we rashly assume CO2 has already worsened the weather. However most scientists share my concern about his maneuverings. As Professor Myles Allen from Oxford University said,  “I doubt Trenberth’s suggestion [reversing the null hypothesis] will find much support in the scientific community.”  Trenberth’s attempt to reverse the null hypothesis has been discussed previously by Dr. Judith Curry and by top rated skeptic blogs, and in a published paper by Dr. Allen “In Defense of the Traditional Null Hypothesis.

Nonetheless many papers are now being published that simply make Trenberth’s assumptions and there is a growing rift between researchers who adopt Trenberth’s “new normal” tactics versus “old school” scientists. The different resulting scientific interpretations are well illustrated in peer-reviewed publications on droughts and heat waves.

A bank account serves as a good analogy to illustrate drought stress.  Financial (hydrologic) stress results from changes in income (rain and snow) versus withdrawals (evaporation and runoff) and the buffering capacity of your reserves (lakes, wetlands and subsurface water). Old school science would demand researchers eliminate all confounding factors affecting hydrological stress before claiming any effect by a single variable like CO2. Here are a few confounding factors that are seldom addressed in papers that blame a greenhouse effect for higher temperatures and stronger heat waves and droughts.

i.)             Clear dry skies increase shortwave (solar) insolation, while simultaneously decreasing downward long wave radiation (i.e. decreasing the greenhouse effect). Reasons for this were discussed in an essay Natural Heat Waves and have been verified by satellite data (Yin 2014). Higher temperatures happen despite a reduced greenhouse effect.

ii.)             In arid and semi-arid regions like the American Southwest, precipitation shortfalls not only decrease the hydrologic “income” but also decrease evaporation. If there is no rain, there is nothing to evaporate. The decrease in evaporative cooling raises temperatures (Roderick 2009, Yin 2014) . Drier surfaces have a lower heat capacity so that incoming energy that was once converted to latent heat of evaporation is now felt as sensible heat that rapidly raises temperatures. Trenberth’s global warming claims often have the tail wagging the dog by assuming higher temperatures cause drier soils. Drier soils cause higher temperatures.

iii.)           Natural cycles cause decadal oscillations between dry and wet years. Recent research (Johnstone 2014) report the past 110 years of climate change in northwestern North America can be fully accounted for by the multi-decadal Pacific Decadal Oscillation (PDO).  The PDO alters the pattern of sea surface temperatures, which alters atmospheric circulation affecting transportation of warmth from the south, and moisture from the ocean. The PDO produces dry cycles that not only reduce rainfall but can increase temperatures via mechanisms i and ii. The negative PDO experienced over the last 15 years promoted more La Ninas that make California drier.

iv.)            The buffering effect of hydrologic reserves has increasingly dwindled. Wetlands have been drained and degraded watersheds have drained subsurface waters resulting in reduced evapotranspiration. The loss of California wetlands since 1820 has been dramatic (Figure 9) generating a decreasing trend in evaporative cooling. Furthermore spreading urbanization has relegated natural streams to underground pipelines. Urbanization has increased runoff (hydrologic withdrawals) as rainfall is increasingly shunted into sewer systems and no longer recharges whatever remaining landscapes are not paved over with heat retaining materials. This increasing reduction in our moisture “reserves” increases regional dryness and has not been balanced by irrigation.

California's Lost Wetlands Has Reduced Evaporative Cooling

The difference between “old school” science and Trenberth’s “new normal” is illustrated in contrasting interpretations of recent extreme droughts and heat waves. For example NOAA’s Randall Dole attributed the 2010 Russian heat wave to a lack of precipitation and a high-pressure blocking pattern that enhanced surface feedbacks. Dole had been studying the effects of blocking patterns for over 30 years since his research days at Harvard. Blocking high-pressure systems pump warm air northward on the systems western flank and trap that heat while clear skies increase insolation. In 1982 Dole had mapped out 3 regions most prone to blocking highs due to undulations of the jet stream.  Those same blocking highs are also implicated in our more recent heat waves that “Trenberth’s school of climate change” trumpet as worsened by CO2. The 3 regions are 1.) Northeast Pacific where the “Ridiculous Resilient Ridge” typically produces California’s drought, 2) North Atlantic that affects Western Europe’s droughts and 3) over northern Russia generating heat waves every 20 years such as the 2010 heat wave. 

Dole concluded in 2011 “the intense 2010 Russian heat wave was mainly due to natural internal atmospheric variability.” Dole’s historical analysis noted, “The July surface temperatures for the region impacted by the 2010 Russian heat wave show no significant warming trend over the prior 130-year period from 1880 to 2009” and he noted similar but slightly less extreme heat waves had occurred periodically over the past 130-year period. The more extreme temperatures could be attributed to “surface feedbacks” from the early season drought and landscape changes. Based on a proper null hypothesis Dole concluded, “For this region an anthropogenic climate change signal has yet to emerge above the natural background variability.”  

Whether or not Dole is correct, Dole is a climate scientist we can trust. A trustworthy scientist, who cannot detect a difference between a recent extreme event and natural extreme events from the past, will simply report that they cannot detect an anthropogenic signal. Whether or not there was a CO2 global warming effect remains to be tested. In contrast less trustworthy scientists will push a non-falsifiable CO2 effect and argue natural variability “masked CO2 warming,” a warming Trenberth insists we must assumes to be present.

Trenberth also appears to hate any scientific claim that weather was just weather. Accordingly he attacked Dole’s “heresy” via his internet attack dogs. Joe Romm blogged, “Monster Crop-Destroying Russian Heat Wave To Be Once-In-A-Decade Event By 2060s (Or Sooner)”, which provided Trenberth an opportunity to denigrate Dole’s analysis in a way not allowed in more staid scientific journals. Trenberth maligned Dole’s analysis as “superficial and does not come close to answering the question in an appropriate manner. Many statements are not justified and are actually irresponsible. The question itself is ill posed because we never expect to predict such a specific event under any circumstances, but with climate change, the odds of certain kinds of events do change.”  

Seriously? Dole’s research was irresponsible because it found no CO2 effect?!? The great value of science to society is that it provides us with some measure of predictability that guides how we best adapt to future events. Dole simply asked, “Was There a Basis for Anticipating the 2010 Russian Heat Wave?” and concluded neither past weather patterns, current temperatures trends, historical precipitation trends or increasing CO2 could have prepared Russia for that event. The only predictability was that similar events had happened every 2 or 3 decades. Trenberth has persistently argued the only “right question” to ask is “how much has CO2 worsened an extreme event, but Dole asked a more useful question. What triggers extreme Russian droughts and heat waves every 20 to 30 years?

Dole’s models, forced with sea ice or ocean temperatures, did not simulate the observed blocking patterns over Russia. Based on several modeling experiments Dole concluded results were “consistent with the interpretation that the Russian heat wave was primarily caused by internal atmospheric dynamical processes rather than observed ocean or sea ice states or greenhouse gas concentrations.” Yet despite Dole’s examination of a great breadth of contributing factors, Trenberth attacked Dole for being “too narrowly focused” because, of all things, Dole did not include July flooding in China and India, or record breaking floods in Pakistan in August. Trenberth was suggesting that that those floods were due to warmer oceans and thus global warming should have been blamed for worsening the Russian heat wave even though Dole’s modeling studies found no such connection.

But Trenberth had the tail wagging the dog - again! Due to the clockwise motion of a blocking High, warm air was pulled poleward and accumulated on the western side of the system driving the heat wave. In contrast the same system pushed colder air equatorward along the system’s leading eastern edge. As discussed in Hong 2011, when that cold air was pumped southward, it collided with warm moist air of the monsoons, and it was that cold air that increased the condensation that promoted extreme precipitation in some locales. Nonetheless, determined to connect CO2 warming to the Russian heat wave, it was Trenberth who was not asking the right questions. He should have been asking how much did a naturally occurring blocking pattern contribute to the southern Asian floods.

As was the case for the Russian heat wave, analyses of the historic heat wave for Texas and the Great Plains revealed no warming trend over the latter 20^th and the 21^st century. In Hoerling 2013, a team comprised of ten climate experts, mostly from NOAA, examined the Texas drought and heat wave. They reported “no systematic changes in the annual and warm season mean daily temperature have been detected over the Great Plains and Texas over the 62-yr period from 1948 to 2009 consistent with the notion of a regional ‘‘warming hole’’. Indeed, May–October maximum temperatures over the region have decreased by 0.9°C.” Thus those experts concluded the absence of observed warming since 1948 cautioned against attributing the heat wave and drought to any warming, natural or CO2 related (However CMIP5 modeled results suggested a 0.6°C warming effect since 1900). Likewise satellite data revealed a radiative signature of a reduced greenhouse effect and increased solar heating (Yin 2014).  

In contrast Trenberth claimed on Romm’s blog, “Human climate change adds about a 1 percent to 2 percent effect every day in terms of more energy. So after a month or two this mounts up and helps dry things out. At that point all the heat goes into raising temperatures. So it mounts up to a point that once again records get broken. The extent of the extremes would not have occurred without human climate change.” But Trenberth’s 1% per day CO2 attribution seems absurd in a regions where maximum temperatures had decreased. His warmer and wetter world meme only obfuscated the issues and Trenberth was again asking the wrong question. The correct question was how much had the drought lowered surface moisture and reduced evaporative cooling that caused higher temperatures? In a region where there had been no increase in maximum temperatures, the amplified temperatures for this extreme weather event were likely the result of natural surface feedbacks caused by a lack of rain.

NOAA’s drought task force also reported on the following Great Plains drought and heat waves. They concluded this drought was likewise due to natural variability stating, “Climate simulations and empirical analysis suggest that neither the effects of ocean surface temperatures nor changes in greenhouse gas concentrations produced a substantial summertime dry signal.” But no matter the level of expertise, Trenberth via his internet attack dog Joe Romm and his blog assailed the Drought Task Force with a less than an honest account. Trenberth assaulted their conclusions, “It fails completely to say anything about the observed soil moisture conditions, snow cover, and snow pack during the winter prior to the event in spite of the fact that snow pack was at record low levels in the winter and spring.”  (But Trenberth’s denigration contrasted with a document-search for the term “soil moisture”, which found it was mentioned about 15 times including the sub-section title in big bold letters “Simulations of Precipitation and Soil Moisture”.) Trenberth’s mugging continued, “There is no discussion of evaporation, or potential evapotranspiration, which is greatly enhanced by increased heat-trapping greenhouse gases. In fact, given prevailing anticyclonic conditions, the expectation is for drought that is exacerbated by global warming, greatly increasing the heat waves and wild fire risk. The omission of any such considerations is a MAJOR failure of this publication.”

But that was a very odd comment for a top climate scientist! Anticyclonic conditions predict droughts will be exacerbated by natural feedbacks, not by global warming.

And again Trenberth failed to ask the right questions. If he believed a greenhouse effect exacerbated the drought by increasing evaporation, then he needed to ask why satellite data has been showing reduced downward long wave radiation and increased solar insolation that typically occur in dry clear skies? In contrast to Trenberth’s obfuscations, the Task Force had extensively discussed the meteorological conditions that inhibited the transport of moisture from the Gulf of Mexico, resulting in reduced soil moisture. Despite low snowpack, soil moisture had not been deficient in the spring. It was the lack of moisture transported from the Gulf that reduced summer soil moisture that raised temperatures and exacerbated the drought. Furthermore modeling experiments performed by the Task Force found precipitation was not affected by changes in sea surface temperatures or greenhouses gases. And historical analyses (as seen in Figure 7) revealed that despite global warming Central USA temperatures were lower than expected given the extreme dryness and expected surface feedbacks. So again Trenberth failed to ask the right questions. Why were temperatures higher during the droughts of the 30s when there was no increased greenhouse effect?

The 2011-2015 drought in California is the most flagrant example of the Trenberth Effect. California’s droughts are most often associated with natural La Nina conditions and a blocking ridge of high pressure that inhibits the flow of moisture from the Pacific to California. Another thorough analysis by NOAA’s Drought Task force again concluded, “the recent drought was dominated by natural variability.” In an interview with the NY Times co-author Dr. Hoerling stated, “It is quite clear that the scientific evidence does not support an argument that this current California drought is appreciably, if at all, linked to human-induced climate change.”

In support of the Drought Task Force’s conclusions, every study of the California drought has reported the major factor driving recent drought has been episodic rainfall deficits. Nonetheless despite the extreme rainfall shortfall there was no evidence of any trend in precipitation amounts or variability that could explain the recent lack of precipitation. Ridging patterns have always reduced rainfall, and the lack of a trend in precipitation contradicts recent claims that greenhouse gases are increasing the likelihood of a ridging pattern that was blocking precipitation (Swain 2014). Nonetheless media conduits for alarmism like Slandering Sou promoted Swain’s arguments. But Slandering Sou is not a scientist nor has she ever published any meaningful science. In contrast climate scientists like Dr. Cliff Mass readily pointed out Swain’s faulty analyses.

Furthermore there is no long-term precipitation trend as seen in the 700-year California Blue Oak study by Griffin 2015. The dashed blue line represents the extreme precipitation anomaly of 2014. For the past 700 years similar extreme precipitation shortfalls have equaled or exceeded 2014 several times every century. From a historical perspective, we can infer there is no evidence that rising CO2 has increased that ridging pattern that reduces rainfall and causes drought. More severe and enduring droughts happened during the Little Ice Age when temperatures were cooler. Clearly land managers and government agencies should prepare for severe periodic droughts whether or not CO2 has any effect or not, testifying to why the Oxford attendees saw little usefulness in CO2 attribution studies.

No Trend in California Precipitation

As expected Trenberth’s attack dogs assailed NOAA’s California report because it attributed drought to natural variability. Romm blogged that the drought would Soon Be More Dire. Over at the Washington Post, Mooney’s fellow yellow journalist Darryl Fears wrote “California’s terrifying climate forecast: It could face droughts nearly every year.” But Fears’ projection has already failed. Despite no precipitation trends, several authors blamed the California drought on extremely high temperatures. Michael Mann argued “Don’t Blame It on the Rain”. Blame it on global warming. To support warming assertions Trenberth blogged a fanciful analogy, “The extra heat from the increase in heat trapping gases in the atmosphere over six months is equivalent to running a small microwave oven at full power for about half an hour over every square foot of the land under the drought.” If that wasn’t fearful enough Trenberth added, “No wonder wild fires have increased!”

But historical analyses suggest the universe had unplugged Trenberth’s “microwaves” over most of California since 1940s, and wildfires were much worse during the Little Ice Age. As shown in the illustration below from Rapacciuolo 2014, observations show most of California, like Texas, had experienced a decline in the maximum temperatures since 1940. If maximum temperatures have not risen there has been no accumulation of heat and California appears to be insensitive to rising CO2. The question that Trenberth failed to ask is why did maximum temperatures decline in his “warmer and wetter” world?

70-year Cooling Trend for Maximum Temperatures in Half of California 

Mao 2012 analyzed the drought in California’s Sierra Nevada and likewise found no trend in maximum temperatures. However assuming the minimum temperature trend was an expression of anthropogenic warming, he used the minimum trend to model CO2-warming effects on drought. But minimum temperatures have little effect on drought. Relative humidity is highest and approaches the dew point during the minimum. Due to daytime surface-heating, turbulent convection peaks around the maximum temperatures and increases evaporation and dries the soil dramatically. But turbulent convection is virtually non-existent when minimum temperatures are measured. Accordingly based on the minimum temperature trend, Mao 2012 found “warming may have slightly exacerbated some extreme events (including the 2013–2014 drought and the 1976–1977 drought of record), but the effect is modest; instead, these drought events are mainly the result of variability in precipitation.”

That brings us to the most recent example of how Trenberth’s “new normal” has undermined science. Williams 2015 claimed CO2 warming had worsened the California drought by 8 to 27%, a claim that was trumpeted by press releases and blogs. To his credit Williams did use a much better version of the Palmer Drought Severity Index (PDSI) that takes into account the physical processes causing a drought. He also pointed out that simpler versions of the PDSI, used by Diffenbaugh 2015, Griffin 2014 and others, had artificially amplified and overestimated the contribution of temperatures to drought (Sheffield 2012, Roderick 2009).

However Williams claimed to have separated anthropogenic warming from natural warming, and used the reversed null hypothesis to do so. Williams warned that he had assumed any warming trend was all anthropogenic. To determine natural temperature variability he simply subtracted his hypothetical anthropogenic-warming trend from California’s observed temperatures. Whatever remained was deemed natural variability. By assuming CO2 is responsible for any warming trend, alleviates climate scientists from the more arduous task of determining natural temperature variability. Furthermore instead of separating out the confounding factors that are known to contribute to higher temperatures, such as the PDO (Johnstone 2014) or landscape feedbacks (as discussed above), Williams simply acknowledged he did not account for those factors as a caveat, then went on to promote his human influence estimated in press releases suggesting he had scientifically linked CO2 warming to drought severity. Without accounting for all factors, Williams’s study was not a scientific evaluation, but simply an opinion piece. Still, as might be expected, Trenberth weighed in calling Williams analyses reasonable but conservative, and recommended that he drop the lower end (8%) of estimated human contribution.

But Williams and Trenberth never asked the right questions. How can scientists assume an anthropogenic warming trend if it hijacks the earlier warming trend before 1950, a trend that the consensus believes was all natural? How can scientists assume an anthropogenic warming trend when there no warming trend for maximum temperatures since 1950? How can scientists blame global warming for worsening droughts when other factors like the PDO, the drying of the California landscape and surface feed backs were never accounted for? 

And more importantly, why should people ever trust Trenberth’s “new normal” science that undermines the very foundation of scientific inquiry. It is more than irksome that my taxes help pay Trenberth’s high salary and allow him to undermine the foundations of scientific inquiry.

In part two: Trenberth’s snowjob, I examine Trenberth’s fallacious argument that global warming causes more snow. 

Pacifica, California’s Natural Coastal Erosion and the Lust for Climate Catastrophes

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 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.” 

The Pacifica CA Erosion Hotspot

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 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.

San Francisco Sea Level 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, 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 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 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.

Pacifica Sea Cliff Backyards before 1997/98 El Nino

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.

Addendum

For those who visit or reside in Pacifica, take a walk along the Devil's Slide trail or hike the bluffs near Mori Point. With luck on a clear day you will be able to see the Farallon Islands that lie 48 kilometers west of the Golden Gate. Eighteen thousand years ago, at the end of the Last Glacial Maximum, the Farallons were the tops of the coastal bluffs that delineated California's coastline. Below is a photograph of the Farallons posted by summitpost.org to the internet.

Farallon Islands sat on California's coastline 18000 years ago