SEA LEVEL: Rise and Fall – Part 1

Guest Essay by Kip Hansen

In remembrance of the victims of Hurricanes Harvey and Irma:  I have held off publishing this essay until after the damage from Hurricane Irma could be determined hoping not to add to the fears, angst and now sorrow experienced by both victims and their relatives.  My prayers and sympathy go out to all who have suffered losses.

 

Sea Level RiseIs it the greatest threat the posed by Climate Change today?

Long_Hunt_beachThe press tells us it is:

“The current best estimates predict that sea level will rise up to 6.6 feet, or 2 meters, by the year 2100.” —  The Climate Institute, “Sea Level Rise: Risk and Resilience in Coastal Cities” by Erin A. Thead

“A rapid disintegration of Antarctica might, in the worst case, cause the sea to rise so fast that tens of millions of coastal refugees would have to flee inland, potentially straining societies to the breaking point. Climate scientists used to regard that scenario as fit only for Hollywood disaster scripts. But these days, they cannot rule it out with any great confidence.   The risk is clear: Antarctica’s collapse has the potential to inundate coastal cities across the globe. … If that ice sheet were to disintegrate, it could raise the level of the sea by more than 160 feet — a potential apocalypse, depending on exactly how fast it happened.” —  The NY Times, Looming Floods, Threatened Cities, a three part series by Justin Gillis

But is it, really?

“Sea level has been rising for the last ten thousand years, since the last Ice Age…the question is whether sea level rise is accelerating owing to human caused emissions.  It doesn’t look like there is any great acceleration, so far, of sea level rise associated with human warming.  These predictions of alarming sea level rise depend on massive melting of the big continental glaciers — Greenland and Antarctica.  The Antarctic ice sheet is actually growing.  Greenland shows large multi-decadal variability. ….  There is no evidence so far that humans are increasing sea level rise in any kind of a worrying way.” — Dr. Judith Curry, video interview published 9 August 2017

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Sea Level Rise (SLR usually hereafter) is being characterized in the press — newspapers, magazines and television reports — as the latest and greatest threat to mankind from human-caused climate change.

Why?  It is always difficult to assign motivation to social memes but it is not disallowed to speculate.  The Global Warming threat has lost much of its appeal with the general public — air temperatures simply have not risen as threatened 30 years ago by James Hansen, despite the changing metrics used to measure and promote it, and, quite frankly, it no longer looks like they are going to.  I needn’t repeat the story of IPCC model prediction failures and the shortfall of actual global temperatures to match their alarming projections.  As we know, the public face of Global Warming shifted from Dangerously Rising Air Temperatures to Climate Change (including Extreme Weather, and Sea Level Rise)  over the last 20 years — though the scientific community has always used both terms interchangeable (for the most part).  But we see fewer magazine covers featuring a flaming Earth — instead we more often see images super storms and NY City underwater with the Statue of Liberty half submerged.

I have written about sea level rise here:  here, here, here, here and here.  The previous essays are not prerequisites but are interesting specific examples.

There are two important points which readers must be aware of from the first mention of SLR:

  1. SLR is a real imminent threat to coastal cities and low-lying coastal and near-coastal densely-populated areas.
  2. SLR is not a threat to anything else — not now, not in a hundred years — probably not in a thousand years — maybe, not ever.

The first of these two facts is a convenient tool for propagandists — those wishing to raise public alarm about “climate change” as a currently-ongoing disaster.

It is easy enough to find some place on the planet foolishly built and occupied within a few feet of local relative sea level at some time in the past which is now flooding at Spring Tides [sometimes referred to as King Tides] or during periods of storm surge.   Given that the average rise of the seas over the last century or so (the total length of our dependable instrumental record) has been about 8 to 12 inches, the chance that occasional tidal flooding will occur in these locations is almost 100%.

The propaganda opportunity is so great that a PR firm has created the King Tides Project to use these naturally occurring “highest tides” to raise the alarm about global SLR.

 

SLR is a real threat to coastal cities — today

First, let’s not kid around — The sea itself, whether rising or not, is a real imminent threat — a clear and present danger — to the many coastal cities and highly populated areas of the world that lie at or very near local mean sea level.

My recent essays on Miami Beach and Guangzhou–Canton point up real-life present-time examples of entire cities at risk from today’s sea level, today’s tides, and already experienced storm surges.  Streets and neighborhoods have been built below Mean High High Water (highest normal tides) and below-ground infrastructure (water and sewage pipes, underground utilities, parking garages, subways) built many feet below sea level requiring them to have pumps to keep things dry and working.

There are not only cities currently below sea level (New Orleans, Amsterdam, Georgetown [Guyana]) but also major portions of whole nations (the European Low Countries and parts of the UK and Ireland among them).  In Asia, Bangladesh, most of which is made up of river delta  less than 12 m/40 ft  above sea level, about 10% of its land would be flooded by 1 m/3 ft of SLR or storm surge.

Any sea-side or estuary-side city with major assets within ten feet of current sea levels are at risk now and those not taking active measures to mitigate those risks are placing losing bets on their futures. The tendency of societies to allow building in harm’s way seems inexhaustible — and to me, inexplicable.

An Example

The megapolis of Los Angeles, California is one of the country’s largest cities (and place of my birth, these many long years ago).  It is nestled in the Los Angeles Basin, surrounded by coastal mountains.

LA_Basin

An inundation of greater Los Angeles would be a truly world-class disaster.  It is home to over 18 million people.

The NOAA Sea Level Rise Viewer, designed to inform us of the threat of sea level rise, allows us to map the inundation that would be caused by up to 6 feet  (2 meters) of sea level rise.  Let’s see what that would look like if it happened to LA — here is Los Angeles Basin, with six feet of extra sea level:

LA_SLR_6ft

Now look at that — almost nothing happens.  From Santa Monica in the north all the way down to San Pedro, almost exactly nothing.  Up near the top , there is the bright green “low-lying area”. Primarily a section called Venice (you guessed it — a developer built canals lined with houses – waterfront homes)  and a little flooding near the Marina Del Rey and Playa Del Rey (the King’s Beach in English).  Marinas are built more-or-less at sea level by necessity — Marina Del Rey in the mouth of a river estuary and a small slough or brackish wetland.  Then absolutely nothing until one rounds the Palos Verdes peninsula (Green Hills) and comes to San Pedro, the seaport of Los Angeles.

Let’s enlarge that portion of the map:

Long_Hunt_beach

Pushing the sea level rise viewer slider all the way up to 6 feet gives us some flooding in the sea port — here there are the docks and warehouses, built intentionally just a few feet above MHHW (mean high high water) so that vessels can be unloaded conveniently.  Circled in RED is an area of light industrial buildings associated with the docks and shipping industry, located along a sea-level river.    The newer Long Beach Harbor area is unscathed.

There is bad news further south-east.  Circled in YELLOW are areas of single-family homes built on what were salt marshes and a sandy, brush-covered sand bar, outfitted with canals so more homes could have their own docks on the water. Leisure World, a huge mobile and manufactured home park, also built in a filled salt marsh is entirely flooded out at six feet.   Sunset Beach is a Miami-like development of canals and water-front homes built just above mean high high water.

naval_stationThe Naval Weapons Storage facility, built at sea level to accommodate loading munitions onto naval vessels, gets flooded, but not the storage areas themselves. The flood-prone portions make up an associated,  not always open-to-the-public, nature preserve.  Close-up views show the munitions storage bunkers built on raised-out-of-harms-way leaf-like islands, far from civilian populations.

 

 

The area circled in ORANGE is shown as already flooding at King Tides.  Let me add that image once more, to keep it in view:

Long_Hunt_beach

Right on the coast in this section is a State Marine Conservation area, but inland in deep water (at six feet of SLR) are literally thousands of single-family homes, cheek-to-jowl.

Just to the south, one half of Huntington Beach is flooded out.  The area now covered with homes was in the 1920s and 1930s part of the great California Oil Boom, and looked like this:

Huntington_Beach_historical

By the 1950’s, the oil boom had moved on, and the low-lying lands were cleared for home-building to accommodate the post-war families cranking out the baby boom.    As we can see from the flood map, little attention was paid to elevation or concerns about the sea.   Riverbeds connect to the sea and bring the rising tides inland where the land is not protected by bluffs — one can see the bluff in the right hand side of the photo above….but further north (left hand side) the bluff doesn’t exist).

 

What has happened here?

Let’s try to be very clear about what has been allowed to happen here.  Humans have been able to measure relative elevation for at least 150 years, since about 1850 when spirit leveling first came into use.

This means that when land is developed near a body of water, like the Pacific Ocean or its connected estuaries, it can be assumed that it was possible to know the differences between the elevation of the water (sea level) and the elevation of the land.  Any time that modern infrastructure — buildings, homes, factories, warehouses — was built, the builders knew (or certainly were obligated to know) the elevation of the land above sea level.

Sea level, worldwide, is understood to have generally risen 8 to 12 inches over the last century.   So all of the areas shown as flooding at six feet of SLR have been built on and developed despite their being 5 feet or less above expected levels of the sea on the day construction was started.

Terminal Island (in Long Beach, the port of Los Angeles) has a tidal range of 5.5 feet (1.7 meters), with Mean High High Water being about 2 ½  feet higher than mean sea level.  The NOAA Sea Level Viewer adds “sea level rise” to Mean High High Water — which can be considered the same as Spring or King Tide.

Mean High High Water is not to be confused with the tidal datum known as “Maximum — Highest Observed Water Level”.   The tide station at Los Angeles, located in San Pedro Bay,  has an historical Maximum that is another  two and a half feet higher than MHHW, meaning that many of these flooded areas have already been flooded at existing sea levels.

 

The Bottom Line for Los Angeles:

Most of the megapolis of Los Angeles is protected from any threat from the sea by the bluffs along its coastline, with some minor exceptions at river estuaries, where some incursion could take place if there was to be six feet/two meters of sea level rise.

Where the greed of developers and lack of foresight by city planners (under the assumption that there was anyone doing city planning) has allowed thousands upon thousands of homes to be built in harm’s way in Sunset Beach, Huntington Beach, Seal Beach and other low-lying beach communities at the southern edges of the LA Basin.  These homes stand at risk under present sea levels, requiring only King Tides and Storm Surges to inundate them with as little as six feet of extra sea level.  As a comparison, Los Angeles has already historically experienced high water half of that in the past. As a reminder, Hurricane/Tropical Storm Sandy recently pushed 13 feet of storm surge into New York Harbor.

 

How much SLR can we expect?

What can we expect from rising seas?  The generally accepted guess is “more of the same” — about 1 foot per century.  If the temperatures rise a bit more, as expected by the luke-warmers in Climate Science, this could increase to about 18 inches over the next 100 years.

Los Angeles, though founded in 1781, did not become a mega-metropolis until after the 1920s, about a hundred years ago and may have seen the one foot of SLR over the last 100 years but it will not see 6 feet of SLR  in the next few hundred years, so they have plenty of time to adapt and prepare.

The situation in LA’s low-lying, at-risk areas will not get much worse due to actual rising seas within a reasonable time scale.  But, with the understanding that some areas are already at risk at current levels, anything other than a sea level drop will make a bad situation worse in those areas.

Neighborhoods built on sea-level canals with only a foot or two of freeboard (the  factor of safety, usually expressed in feet above a sea level or MHHW) will probably have to be abandoned over the long term.  Building codes will need to be enacted forbidding building on low lying areas prone to sea water inundation. All new homes built in flood-prone areas should be mandated by code to be built on “stilts” or with living spaces raised on eight to ten foot foundations as they are now in some East Coast areas.  Existing homes in many areas will have to be raised or when next flooded, abandoned.

Southern Florida has been making these types of changes in building codes and development requirements for the last ten years, along these lines, requiring new homes to be at least a foot above FEMA flood map levels.  Sea walls, when newly built or repaired are required to be raised to match expected flood levels.  New homes in the Beaufort area of North Carolina (and all throughout the low country as it is called)  can be seen going up in compliance with codes requiring living areas to be raised — most often ground level is dedicated to  garage and storage space, and the living spaces up one floor.    The following image shows (in light blue) how much land would be flooded by 6 feet of SLR or storm surge.

NC_SC_low_country_6ft

As a personal note, my wife and I sat out Hurricane Irene in August 2011,  near Beaufort, NC, in a tiny marina along the Atlantic Intracoastal Waterway, about three miles inland.  There we had over 8 feet of storm surge.  We watched as the docks and the pilings disappeared under the rising waters.  We had our car parked on a hill 10 feet above MSL, it was touch and go through the night whether the hill too would be flooded.  (On the map above, Beaufort is just south of the “ville” portion of the city name for Jacksonville.)

The Future

The Low Countries of Europe have long ago developed the engineering skills necessary to deal with and mitigate past errors of building too close to sea level. The rest of the world’s nations and cities each need to carry out an exercise similar to the one above — and as was done in Dade County — much more detailed and exacting on the level of professional civil engineering and develop mitigation plans for their current situation and for the expected continued rise in sea levels over next century — mitigation plans that will correct for past errors and oversights and protect them in both the short term and the long term.

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  1. local relative sea level — the average level of the surface of the sea in relation to the land at any given locality. NOAA says : Tide stations measure Local Sea Level, which refers to the height of the water as measured along the coast relative to a specific point on land. Water level measurements at tide stations are referenced to stable vertical points (or bench marks) on the land and a known relationship is established.” (back to essay)

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Author’s Comment Policy:

I am always eager to read your comments and to try and answer your on-topic questions.

Try not to jump ahead of the series in comments — this essay covers only the existing sea level threat with a single example (added to the examples in my previous sea level essays).  I will cover, in future parts of the series: How is sea level measured?  Do we know that sea level is really rising? How fast is it rising?  Is it accelerating? How do we know?  How accurate are sea level measurements anyway?  Should I sell my sea front property?

Sea Level Rise is an ongoing Scientific Controversy.  This means that great care must be taken in reading and interpreting new studies and especially media coverage of the topic  (including this essay) — bias and advocacy are rampant, opposing forces are firing repeated salvos at one another in the journals and in the press and the consensus may well simply be an accurate measure of the prevailing bias in the field.  (h/t John Ioannidis)

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169 thoughts on “SEA LEVEL: Rise and Fall – Part 1

  1. If the property to be flooded by sea level rise is valuable enough, build dikes and a pumping system, Otherwise, write it off. Less than a third of a meter in a hundred years allows more than enough time to do the work.

    • Indeed, just look at the “property” wiped out in the Keys: mostly mobile homes.

      BTW

      Humans have been able to measure relative elevation for at least 150 years, since about 1850 when spirit levelling first came into use.

      Roman and Egyptian engineers understood relative elevation, we did not need to wait to invest the spirit level.

      • Greg ==> The Romans also understood how to build real road beds — thus there are still usable Roman roads 2000 years later.

      • RWTurner ==> Interesting. The wiki article lacks maps and graphics, so folks like me unfamiliar with the geography have trouble understanding exact;y what is being described. If you happen to be expert in the region, perhaps you could edit the article.

        If not, I believe we have some folks here from the region that might be able to improve the online encyclopedia on this issue.

    • I spent fourteen years in a cottage 6 feet below the level of the river 300 yards away.
      In a place that used to be drained by windmills, but as soon as steam engines came they used those, and thereafter diesel and now small electric units.

      Did you know that the greatest danger came from moles, undermining the earth dykes?

      Mole catching was a lucrative profession once.

      Anyway, coping with slowly rising sea levels is simple enough and a lot cheaper than renewable energy.

      You surround ‘polders’ with earth dykes (levées in USA spik?) – and that’s a handy place to put the roads, and you pump the polders dry with electric pumps.

      Some of these polders are allowed to flood if water rise cannot be coped with.

      In the case of river valleys subject to tidal flows, a tide barrier can be constructed as e.g. has been done in for London.

      Unless sea rise is massive and rapid as may have occurred when the straits of Gibraltar were breached* – its not hard to cope with it.

      Some protection, some abandonment.

      *https://en.wikipedia.org/wiki/Zanclean_flood – 10 meters a day is hypothesized.

      • Leo ==> New Orleans is built on that plan …. but nothing is fool proof. Dikes, poorly maintained, breached, power to the pumps went out, and New Orleans drowned.

      • This is the Cruquius steam pump, that drained the Schiphol polder, within which Amsterdam Schiphol airport is built. (12 ft below sea level). Yes Schiphol seems to be dry 24/7/52, without any iminent threat of inundation.

        The Cruiquius steam engine was built by Harveys in Cornwall, and is claimed to be the biggest ever built. (9 high pressure cylinders that surround a huge low pressure cylynder). But I think the Crossness beam engine on the Thames is larger, and is a masterpiece of Victorian architecture – more like an ornate museum than a pumping station.

        The Cruiquius pumping station….

      • The Crossness sewage pumping station on the Thames. Now THAT is how you build national engineering infrastructure (when the country is confident and prosperous……..)

    • Most buildings are only built to last 60 to 70 years. SLR is so slow that the solution is simple. Wait for the buildings in harms way to finish their natural life. Then instead of replacing them, tear them down and rebuild a mile or two inland.

      • Mark ==> Many places have this rule in place – for homes, for docks, etc. You can live in them now, but if they are damaged severely, you may not rebuild. In many areas, this leads to non-reporting of serious damage and midnight home repair outfits that work after hours, secretly gutting and rebuilding the interior of a house without anything showing on the outside one month, then “re-siding” and “re-roofing” the next month — resulting in an essentially new home where the old one stood.

      • That is unless your the mayor of any of the cities being effected. Then all the problems are due to climate change and the Federal Government (ie: American tax payer) must be made to pay for years of greed and poor planning. Was driving the big truck and tuning the radio came across an NPR program in which the mayor of Tampa was being interviewed. Was surprised at the tone of the interviewer who asked something to the effect: ‘Tampa has dodged a bullet from the recent hurricane but it can’t expect to remain so lucky. What are your plans Mr. Mayor to address the problem of so many years of poor decisions in the placement of developments which have continually been allowed to be built in the low lying coastal areas?’

        The mayor first did the usually meaningless two bit shuffle and then launched into how the current administration must take climate change seriously and it was a tragedy it didn’t.

      • Mark – yes, or do what we’ve been doing in Florida for decades – if you want to retain your waterfront, or near the water home, build upwards. Instead of putting the first floor at natural grade, elevate, either with stem wall foundations, or build on pilings (as some call them, “stilts”). The space between the first occupied floor level and ground is still useful space, because it will flood only momentarily on a rare recurrence rate. Use it for storage, garage, put your barbecue grill there, etc.

        We have been establishing required “first floor elevations” by building code and FEMA flood maps, periodically revised, for many decades now in Florida. No big deal.

      • Duane,
        Yup, Northern Australians have been doing this for decades. Google Queenslander style.
        Chicago raised the whole city one story back in the day. We’re probably too politically insipid to do that today.

  2. Sea level has often been higher than now during the Holocene. It’s rising naturally, as a result of leaving the Little Ice Age, but its rate hasn’t increased in this century and didn’t in the last one. And the long-term trend is still down, as it has been for more than 3000 years.

    MSL was naturally higher during the Holocene Climatic Optimum, the Egyptian, Minoan, Roman and Medieval Warm Periods than now. Despite southern Britain’s rebound from the loss of ice off of northern Britain, Roman coastal forts and Medieval coastal castles are now high and dry there.

      • Tidal gauges for south Britain (e.g. Newlyn, Sheerness/Southend) show sea-level rise pretty much at the 100-year global average of 1.5-2 mm/year. Perhaps rebound has most of its effect at an opposite edge of a crustal plate, contributing to greater rise along the northern shore of the Mediterranean, and along the much-discussed Atlantic shore from New York City to Houston.

      • sixto and David ==> Ancient history neither increases nor lessens the danger that many localities face today from their relationship with the sea. All that matters is today’s local Relative Sea Level and the level of your city, home, etc.

        Changing sea levels only affect those areas for who sea level is an issue at all — rising sea levels make bad places worse (albeit slowly in most cases).

      • Kip,

        It just puts sea level rise into perspective. Any place that is threatened by 1′ of sea level rise per century is already being flooded by high tides, seasonal & annual sea level fluctuations and storm surges. You characterized it very well here:

        First, let’s not kid around — The sea itself, whether rising or not, is a real imminent threat — a clear and present danger — to the many coastal cities and highly populated areas of the world that lie at or very near local mean sea level.

        The sea is the imminent threat. SLR is not.

      • The NOAA Sea Level Rise Viewer, designed to inform us of the threat of sea level rise, allows us to map the inundation that would be caused by up to 6 feet (2 meters) of sea level rise. Let’s see what that would look like if it happened to LA — here is Los Angeles Basin, with six feet of extra sea level:

        […]

        Now look at that — almost nothing happens.

        And “ancient history” tells us that 6′ of SLR is not possible over a human lifetime under amy rational scenario.

      • The challenge for the civil engineers of modern ports isn’t a tiny sea-level rise of less than an inch. It is, and always has been, tsunami and huge storm surges. A once-every-500-year storm will create a sea-level rise greater than 500 years of gradual melt, and will do it all at once, with no time to build dikes.

        Often engineers are not given enough money to build for a once-every-500-year-event. In such cases cities should have a contingency plan for what to do when the engineering is overwhelmed.

        For example, there are suspicions that Boston’s “Big Dig” may not be able to withstand the stress created by huge storm tides that seem to have occurred in the 1600’s, when the thousand-mile fetch of prolonged easterly gales piled water into Massachusetts Bay. Can the roofs of certain tunnels hold up with an extra ten feet of water pressing down? Or with water pouring down ventilation shafts?

        If people insist upon sitting about dreaming up worst-case-scenarios, engineers can think up better ones than Global Warming Alarmists. For example, on very rare occasions Pacific Hurricanes neither go west out to sea, nor curve east into Mexico, but rather zip all the way north and cut inland over Los Angeles. Then you’d get the six-foot sea-level rise envisioned by the above maps in a matter of hours, with the addition of waves surfers drool over.

      • Funny thing. On another Internet forum thread about Irma, this came up:

        Normally it’s not too big an issue within The City as we have extensive sea walls, but since Sandy’s surge broke the ~200-yo record by nearly two feet, suffice to say that it was eye-popping. I mean, how does one plan for a 200-yo record not being merely surpassed, but outright shattered? Most of our sea walls were built to 10′. The old surge record, set ca-1827, was 12′. The Battery’s 10′ walls hadn’t been surmounted since Floyd in 1999. Sandy’s surge was 13′ 9″. Is it even possible to plan for something like that?

        I replied… 4.5 m (15′) should be adequate…

        To which the other person replied…

        That makes sense if we ever challenge the record set in 1638 (how did they measure that one? ) Now excuse me while I warm up the time machine . . . . Economically speaking, how feasible is it to build for an event that occurs once every 374 years?

        To paraphrase the legendary Steve Mosher… I people won’t even prepare for 374-yr events, how can we ever get them to plan for 500-yr events? ;)

      • First attempt at a major Texas port was Indianola, wiped out in 1886. Second attempt was Galveston, wiped out in 1900. Only then did Houston get the nod.

        In some ways we humans do things by trial and error, learning from pain and blunders. Only in Ivory Towers is there never a mistake. Even the amazing days when NASA actually landed on the moon saw loss of life and tragedy.

      • David ==> a pleasant experience to be understood….

        Can you supply a link to the graphics you have posted (the pinkish ones)?

      • Kip,

        I’m worse at record-keeping than Phil Jones and Michael Mann… combined. The original PowerPoint is on one of my many memory sticks, on my old laptop or possibly my office PC. I know it’s not on my new laptop… because I’ve already looked there.

        I’ll dig up the original sources. That shouldn’t be nearly as difficult as finding my own work… ;

      • Blum et al., 2002 (not 2003), Texas Gulf Coast, adapted from figure 7A…
        http://usuarios.geofisica.unam.mx/gvazquez/estratiGAB/Zona%20desplegar/Lecturas/blum_et_al_2002.pdf

        Baker et al., 2005 is in Figure 4 of this paper:
        https://research.jcu.edu.au/tropwater/publications/Lewisetal2008MidlateHolocenesealevelvariabilityineasternAustralia.pdf

        Jameson et al., 2012 Qatar, page 9…
        http://www.searchanddiscovery.com/documents/2012/50704jameson/ndx_jameson.pdf

        Figure 4 from Lewis et al., 2008 is also in this presentation.

    • Caleb ==> Yes on this:

      “For example, on very rare occasions Pacific Hurricanes neither go west out to sea, nor curve east into Mexico, but rather zip all the way north and cut inland over Los Angeles. Then you’d get the six-foot sea-level rise envisioned by the above maps in a matter of hours, with the addition of waves surfers drool over.”

      I have seen this and surfed this (at Huntington Beach — a truly terrifying experience — but then I was young and extremely foolish).

    • Thanks for referring to this excellent paper. Summarized: There is no visible CO2 signal observed in any of the tide gauges with records exceeding 100 years. Since 1880, CO2 has risen at an accelerated exponential rate (38%) while tide gauges remain linear – rising or falling determined by local tectonics, but linear nonetheless!!!

      • …yes and when adjusted for land rising or sinking, about 1.5 to 2.0 mm per year.

        U of Colorado is very late on their SL rise info?? WUWT?

  3. I have held off publishing this essay until after the damage from Hurricane Irma could be determined hoping not to add to the fears, angst and now sorrow experienced by both victims and their relatives.

    Funny, all the climate alarmist had no issue instilling fear, angst and prophesy at the impending doom before the Hurricane’s even hit.

  4. Is there any work or study regarding whether the contentinent or parts of the continent are rising or falling due to shifting tectonic plates?

    What if near certain parts of the ocean the land is slightly sinking ?

    • Doug ==> NOAA CORS project is measuring the vertical movement of land masses — as well as their North/South, East/West movement.

      There is barely enough data to do good analysis as yet, but rough averages can be calculated for many locations. NY City’s Battery is currently subsiding by about 1.3/mm per year.

    • A couple of areas come to mind. The most interesting is the Chesapeake Bay impact crater. There is a large crater roughly centered on the southern end of the delmarva peninsula that extends westward to the west shore of the bay. The land all around is slowly slumping into the crater, and since it is coastal, it causes a greater than normal apparent SLR in the local area. Coincidentally (or not) this area is often cited for sea level problems.
      Another area is coastal Louisiana where there is some evidence of land subsidence due to oil and gas extraction. Because the land is very flat and very low any subsidence has a magnified effect.
      There is not going to be any halting of building on the beaches. It is the most desirable place to live. I remember video from Bangladesh after a tsunami had killed several hundred thousand people and had wiped the beach clean. The next morning the beach was swarming with people building new homes on those beaches – those were people who had survived on higher ground purposely building on what had been wiped out the day before. Many Floridians like living ON-the-coast, not inland a few miles. The climate is much nicer within a mile or so of the coast – sea breezes and such. They will build and live there regardless of intermittent threats, and evacuate if the threat is immediate, and rebuild if it is realized. And if there is nice freshly wiped beach someone will be ready to pay dearly for it.

      • People used to build cheaply on the beach – now with the government in the Insurance business taxpayers subsidize extravagant homes in places of peril. They mess up everything they touch.

      • Shawn ==> Honestly, I think it is the advent of Building Codes — long gone are the days when one could knock together a pleasant beach shack for your family’s use during the summer — and go out and repair it every few years after major storms. Now codes require that you build a real house — even if you just want a shack.

  5. It isn’t just the sea that causes floods – we need rational policies towards any area that historically floods as well as ones aimed at the gradual sea level rise. It never ceases to amaze me when people brag about “rebuilding” their homes for the second or third time (typically using government funds) because of flooding. Why it doesn’t occur to people that this is a bad idea is puzzling.

    Coastal areas should enact policies to reduce the tendency of people wanting to build close to the water – instead make these areas close to the water “public lands”. This protects property from rising sea levels and hurricanes.

    Obviously building higher than any expected flooding makes sense as well – coastal or river. Either build away from the area on higher land, or raise the level of the land, or raise the level of the buildings. I personally do not trust dikes – anything built and maintained by the government is going to be suspect over time.

    The time following big disasters like Houston and Florida is the time to start correcting the defects. Trump wanted a big infrastructure project to stimulate the economy – well here is the chance.

    • Robert of Texas ==> Flooding in Houston is no surprise to anyone — Houston has been flood-prone since before it was built. See any topo map of Houston (try this link for a pdf) the link is to a topo map of the University area. Hardly a five foot difference to anything.

      Texas flooding is legendary.

      Despite this, there have not been crash programs to build drainage canals such as those in the Los angles Basin. Use this map and zoom in on the 10 and 105 intersection, turn on all layers. You’ll see what Houston has not done.

      • Mr Hansen – Thanks for a good piece of reporting and science. I must point out, however, that Interstate 10 and Interstate 105 do not intersect. Did you mean the 101 and the 105?

      • Retired (as am I) ==> Lousy map — when I lived there we didn’t call the freeways by number — they had names.

        I did mean the 105 and the 110….though … The 110 was the Harbor Freeway, the 105 didn’t exist.

      • gary ==> Look at the graphic in the second link. The sinking to towards and to the river that leads to the bay — the text claims that water will not flow out of that dent — but that is clearly false, it flows directly into the bay at the spot marked -10′.

        Truthfully, this looks to me to be the expected subsidence from building on what used to be marshland or seasonal marshland — the shape and location is very indicative of this effect — sloping down to an estuary. Marshland normally get sediment washed into them which balances out the subsidence. When cities are built, rivers and streams get channeled to flow quicker, and sediment ends up in the sea instead of rebuilding the marsh.

        Could be a combination of the effects of ground water/oil/gas extraction and normal marshland subsidence.

    • The original Oregonians were pretty smart, not so much anymore. Too many Progressives have infiltrated the state. But Govenor Oswald West set aside almost all of the beaches, I believe up to the high tide mark as public highways. This goes a long way toward realizing Robert of Texas’s suggestion of “public lands” concept. Now we just have to hope the Cascadia Fault doesn’t break loose.

      • Dan, I am not so sure that reserving all the land “up to the high tide mark” would rate even as high as a no-brainer. If you don’t have a proper sewage system, building your house in the inter-tidal zone is okay, so long as the population is small. For me, I reckon you need a good sea wall in place if you are building on anything less than solid rock at the ocean’s edge.

      • Ray B ==> What the Oregon law does is give the pubic free access to the beaches, at least seaward of the high tide line, and makes private ownership of the beach nearly impossible.

  6. What I would like to see is a compilation of storm surges experienced by cities, both in the U.S. and elsewhere, that occurred before 1950. If such a list has already been posted, my apologies. I know there.was a recent post concerning the 1900 Galveston hurricane. Didn’t New York/New Jersey experience storm flooding before Sandy, as well?

    SR

    • Steve ==> NOAA Tides and Currents keep records of tide gauges around the United States (and a few other places) and establishes “datums” for each spot. One of these is MAXIMUM, which is the maximum high water every experienced for any reason (usually represents storm surge) and gives a date.

      Mayport, FL (the tide station associated with Jacksonville, FL) can be found here. That link is to the datum page for that tide station. It shops on the left hand side that the datum named Maximum is 5.72 feet above the local Mean Sea Level and 3.2 feet above Mean High High Water (the highest high tides).

  7. Suppose the sea level was essentially stable and perceived to be so. What percentage of buildings standing today (say in present dollar value terms) would we expect to still be standing by the year 2100? It seems like the mitigation challenge should be gaged in the context of this normal replacement rate.

    • Michael ==> Of course, mitigation plans should take into account normal attrition, and not all areas, not all neighborhoods, not all cities for that matter, should be “saved” — the same way that not all buildings are preserved in urban renewal plans. The homes of the uber-rich should be allowed to perish if they don’t wish to invest in their protection — tax dollars should not be wasted on these million dollar beach homes that never should have been built.

      Miami’s canal neighborhoods could be torn down and made into nature parks and allowed to flood periodically, etc.

      • ‘Neighborhoods built on sea-level canals with only a foot or two of freeboard (the factor of safety, usually expressed in feet above a sea level or MHHW) will probably have to be abandoned over the long term.’

        Or, do as they do in the Netherlands and build houses on floating concrete ‘barges’.

      • Kip,
        I don’t know if your comment is correct. The federal government sponsored flood insurance only covers $250,000 limit plus $10,000 for contents. Is there anyway the uber rich get more from the state or elsewhere?
        I think the uber rich who lost their homes used their own money to restore homes that cost more than the allowance, I know of one case. FEMA did raise the elevation requirement by 1 foot increasing the cost for flood insurance cost
        I have a nice 2700 ft^2 lagoon front, summer home built in 1986 at the NJ shore that has never flooded, although Sandy was close.
        The insurance would cover the structure but not the value of the land at least that is my thinking. For me to loose a lot of $$ , the lagoon property would have to be destroyed on declared un-build-able which is not likely as raising the house on piling is always an option.

      • Flood insurance does not consider the land only improvements to the land. However, if you have a mortgage you must cover the mortgage amount which usually includes the price of the land.

        BTW, I finally got my power back yesterday at 5 PM. Got to wondering, how could a power grid supplied solely with wind and solar possibly be able to get so many people back on line in just a few days. Remember when we all get power restored everyone switches on everything all at once. That’s thousands of household and commercial properties producing a massive power drain all at the same time.

      • Tom ==> The solution to this problem can be found in the alternate energy playbook. It is used throughout the Third World where one can not count on the power gird to supply 24/7/52 power. My wife and I lived with such a system in the DR for a year. The system below provided all the necessary power for a modern household, including a swimming pool (in the living room) and all its pumps and filters.

        One installs a battery bank – 8 to 10 12vdc deep cycle batteries with an appropriate sized inverter/charger. This is backed by a diesel/gasoline/propane/natural gas generator (gen set).

        Short power outages are handled by an automatic switching to the inverter supplied 120vac converted from the batteries. If your solar panels haven’t blown away, they will start charging the battery bank as soon as the clouds blow away and sun reappears.

        Longer outages are covered by firing up the gen set.

        In emergencies, the gen set powers the house, charges the battery bank, allowing the gen set to be turned off at least for the ten hours of sleep time, conserving fuel. A fifty gallon fuel oil tank can see one through quite a long disaster this way.

        Low-density power sources, like solar and wind, at the present can not be ramped up quickly enough to power disaster recovery.

        Break-throughs in energy storage (solid state batteries, maybe) will someday supply backup to grids, regardless of the primary source of the power.

  8. Raised beaches on the north coast of Greenland, ice-locked for centuries (A study by Danish researchers) has driftwood, sand dunes at the back, “plowing” by pushed ancient ice onto the beach, etc. Wood was dated at.~6000ybp. The development of the beaches and its features required a substantial area of open water out from the beach where winds could drive waves, and driftwood could be delivered.

    https://www.sciencedaily.com/releases/2008/10/081020095850.htm

    In the Caribbean, the shore cliffs are notched several metres above current sea level, demarking an earlier sea level high. On the north coast of Dominican Republic, I examined one such notch which was in coral that made up the entire cliff, and even above that, inland at an elevation some 10m above sea level, coral outcrops that must have been several metres more below sealevel there when it was alive.

    https://www.mona.uwi.edu/geoggeol/mgu/Coastal%20Hazards/SEA%20LEVEL%20RISE.pdf

    • Gary ==> I have seen many notched cliffs and ancient coral heads in the northern Caribbean. What we can know from these is that the local Relative Sea Level has changed — but not what this has to do with Global Sea Level. We can not tell if the land rose up or the sea went down. we only know they changed their relative altitudes.

      NOAA CORS will eventually tell us more,data sets need to be quite long, and we will only then know for the time actually measured.

  9. I have a house on a creek off the Chesapeake Bay. It’s on the water but sits on a mini-bluff about 10′ above it. Hurricane Isabel pushed water into the creek 4′ or so above high tide until the wind shifted 180 deg and it all rushed out. That has been the highest water I’ve seen there.

    Another foot or two will not make a difference and will actually benefit me giving me another foot of water at my slip which would let me dock a sailboat with a deeper keel. Plus the Bay is relatively shallow and more water will help navigation.

    Kind of like CO2 where more is actually better.

    • rbabcock ==> I have a sailboat I need to leave in the Chesapeake this winter….where are you located? Know of any decent inexpensive slips (with basic electric)?

  10. One of the unintended consiquences of cheap government subsidized flood insurance is that it allows fools to build in flood planes and other at risk areas. If you want to build there,fine. But pay full load for your insurance and don’t expect bailouts when the inevitable happens.

    • Fraizer ==> Revkin and Pielke Jr have been pounding on this point for years….I have repeatedly written about it. It is the simple greed of developers and the foolishness of city planners to allow building in harm’s way — not really the flood insurance plans — though the law should only allow flooded out homes to be rebuilt with insurance pay outs OUTSIDE of floodplains and not allow rebuilding in the same stupid place.

      • “the foolishness of city planners”

        And the local-boosterism + self-interest of city officials, who want a bigger tax-base.

      • Planning and regulations, when enacted and enforced, do make things safer. They also increased costs, time, and frustration.
        While I live at 2,240 feet and sea level is not an issue, there is a small stream that runs through the property.
        Initial flood plain zoning used a simple map. The steam was overlain with a series of short straight lines and the flood plain was marked on either side at 100 feet out. No regard was given to the height of the land. This silly approach is now being re-done using modern technology.
        The county building regulators, not planners, dictated where I could have a hay barn (pole barn) built. An inspector visited (1st) to be sure the holes had proper footings – that took 10 minutes, and (2nd) to count the number of bolts holding the trusses to the poles – another 10 minutes. There was driving time, a total of about 1 hour.
        The county demanded almost $700 for their advice and inspections.
        I hired a respected builder. He did not need their advice nor the inspections.
        Still, I’ve got a very nice hay barn.

      • Kip,
        Unfortunately, this is part of a similar problem, particularly in California. People build expensive homes on cliffs of unconsolidated sediments overlooking the ocean. Storms undercut the cliffs and the homes are demolished. People with more dollars than cents build homes on flat areas in the coastal mountains — the flat areas are invariably the toe of old landslides and when loaded with a structure and cars, and watered to keep the grass green, they typically reactivate. Personally, I wouldn’t care if they took their inevitable losses, but they want special treatment for a short tenure of spectacular views.

      • Clyde ==> It is a mystery to me….although I do understand the esthetic value of the night view south from the ridges of the Hollywood Hills….absolutely priceless. I would hope the the insurance companies charge the homeowners there for the additional risk involved.

        The ocean cliff houses I understand less well…. looking out over the seemingly endless Pacific Ocean during the day doesn’t appeal to me, the constant wind irritates me, but there is pleasure to be derived from the sunset-over-the-sea hour. (Here on the East Coast, we get sunrise over the sea).

        After eleven years in the Caribbean I became a bit jaded about what I referred to as “just another beautiful sunset” — we must have a thousand beautiful sunset photos stored on hard-drives…..each one suitable for National Geographic.

      • Kip there is a widely used option of raising the house on pilings in the shore communities. It involves extra cost but can make sense in many cases. The building codes along the NJ coast require all new and rebuilt homes to be elevated.
        Total ban of building does not make sense in all cases.

  11. Here I sit with the sea on three sides of my house. We have huge tide swings ( +20 to -4). My house is located at about 30 feet above sea level, or about 10 feet above the highest tidal swings. God how I love this place. I have never been worried. A tsunami could really cause problems, but so far, every tsunami warning has made no detectable change in the sea levels. I have no flooding insurance, and I don’t care. I argue with my liberal friends that global warming hysteria is bunk, and I live accordingly.

    • Haverwilde ==> Sounds lovely — what part of the world are you in?

      I have spent more than 1/2 of my adult life living on the sea, on ships and boats. So I just go up and down with the tides….even the storm surges. I do not however, like to be out in anything worse than a Force Seven or so seas. (High wind, moderate gale, near gale) . Getting too old for that kind of excitement.

  12. There is just no end to the risks you can name to your existence where ever you live – we just really have to trust our luck. It is a comfort to bear in mind that we only die one death each – which is bound to happen to us anyway, eventually.

    You forgot to mention the very real risk of a tsunami (like the one in Lisbon a few hundred years ago), caused by the Pacific – American fault-line. That, within a few minutes, could stir things up in Los Angeles (worse than climate change!).

    • AndyE ==> A tsunami would have to be pretty big to seriously threaten Greater LA — but of course would be horrifically damaging in direct relation to its height. Much of the beach front of Los Angeles, from south of Venice to Palos Verdes is backed by a bluff (really a huge sand dune) that is quite high — 100 to 200 feet in Hermosa Beach for instance. Of course, the ocean side of the bluff is covered with homes and businesses, all the way up to the top.

      • One caveat with regard yo a 6″ LA rise. Certainly it would cause a great deal of erosion within a relatively short time. ( fortunately at current rate of so rise we have 1000 years or so…)

      • David a ==> The generally touted idea that rising seas increase erosion is an unsubstantiated alarmist talking point.. A slowly rising sea simply changes where the water hits the land, but not its nature or its action. On LA’s wide sandy beaches, the waves would simply be breaking nearer the boardwalks (they are cement, but we call them boardwalks). At Palos Verdes, the waves would be breaking higher on the cliffs and the ever changing cliff-face would still be ever changing.

  13. I have been very surprised that the sea level increase has not accelerated higher. We have seen an increase of global temperatures of around 1 Deg. C over the last century, with the increase greater at the higher latitudes. Obviously, in the Arctic, when you melt sea ice, you don’t have an effect but with warmer temperatures at higher latitudes, there should be more melting of land ice(including mountain glaciers and ice sheets).

    In addition, there is thermal expansion of the oceans from the warming. Maybe this should be adding another 25-30% to the increase in sea levels. In addition, we have been pulling out a lot of water from underground aquifers that makes its way to the oceans via runoff. This may have added an additional 20% to the sea level increase vs a century ago.

    The 3 factors above, all should have accelerated the increase in the sea levels and it should be very obvious by now.
    How is this not happening? Is there an increase in evaporation from the oceans from the warming, that’s increasing rains enough so that this water is being relocated to land? Has global soil moisture increased?

    Maybe its increasing snow in Antarctica that is stored but that amount should be small compared to the expected increase from the factors above. Global precipitation has gone up.
    Some of it is in the atmosphere. Precipitable water in the atmosphere has increased with the global warming but that amount is not nearly enough to explain why the sea levels are not going up faster.

    https://www.climate.gov/news-features/event-tracker/rising-atmospheric-moisture-global-warming-not-blame-2013-colorado-flood

    It doesn’t add up unless global temperatures are not warming as fast as what we think or there is a lag of numerous years or I am just overlooking some things.

    • Mike ==> The entire Earth Hydrologic system is very complex — meaning “it is not that simple”. I suspect that it is as non-linear as the atmospheric system and the ocean system.

      There have been lots of studies trying to sum up all the bits that earth scientists think should add up to the rise in the seas……but they mostly just agree with one another — but not the actuality.

      I will be writing an essay in this series but how sea level rise is measured/calculated.

      • ZThomm ==> In all honesty, we (humans) do not know exactly what is causing the sea to rise in anything other than a general (common) sense — the water in the seas is warming up (still, after both the last Ice Age and the recent Little Ice Age) and expanding a bit (this is why we can make water-in-glass thermometers – water expands evenly when warmed) and maybe the little jitters in the long term (NASAs Ground Data) graph are caused by things like more rain, less rain, more ice melt, less ice melt — we just don’t have data to the precision (or accuracy) that is needed to sort this out.

        The Ground Data shows that nothing out of the ordinary is happening – 20 year slow down in SLR rise from 1910-1930, a rapid-ish 20 year rise from 1930-1950, and then steady-on the long term trend since then, with the expected little jitters.

        I think that the two-or three year slow down on the Satellite Data graph is just jitters — as is the whole Satellite Data series…..

        In an upcoming part of this series, I will lay out just how iffy all of this data is….the bottom line is: The seas have been rising slowly for at least the 150 years that we have measurements for, at a more-or-less steady rate, and we have no reason to believe that rate is changing very much now or will change in the future.

        In the Satellite Data, remember they are talking of discerning a 3 mm change in the average level spread over 361.9 million square kilometers (139.7 million square miles) of ocean. 3mm is the thickness of two American pennies stack on top of one another.

    • Mike Maguire September 13, 2017 at 8:43 pm: “Has global soil moisture increased?” and “It doesn’t add up unless global temperatures are not warming as fast as what we think (…) ”

      WR: An interesting question you are posing: why isn’t sea level rising more? First of all there is the risk that the higher temperatures that are mentioned for a considerable part only exist in some overheated computers. Adjusted temperatures. But it is also possible that soil moisture (as one of the factors) has increased. The growing CO2 could be the cause. Because of CO2 the Earth is greening, not only above ground level, but also below the surface. A considerable part of the biomass (20-40%?) grows below the surface and stays there. Extra biomass above means extra biomass below the surface. After plants and trees die, the remnants in the bottom will stay there for a part, forming brown and black soils and thick layers of peat. Those bottom types behave like a sponge, so they suck up water.

      • Increasing biomass from the greening earth, below and above the ground is something that I never considered. Studies of plants under CO2 enriched environments do show a huge increase in root mass, which would be below ground.

        I know that woody stemmed plants have accelerated growth the highest, up to 50%, which would include the worlds forests/trees. That might explain part of where the unaccounted for increase in water(expansion) is going.

      • Post Comment
        Mike Maguire September 14, 2017 at 6:31 am

        WR: Mike, it is not only the biomass under the ground, but the sponge effect as such that is very important also. Think about the millions of small thin roots that are able to retain water in sandy soils. Also the quick run off is diminished by the plants above the soil, causing more rainwater to enter the soils.

        Besides, former desert and semi desert areas that show the highest greening rates will contain biomass and sponge effects in the soil where there was hardly any sponge effect, changing the water retaining qualities of the soil dramatically.

        The more the world is greening, the more water will be retained on land.

        And, the growth of the number of water basins and their water leakage into the subsoil also play a role.

      • Mike ==> On average, living plants are 80-90% water — so added living plant biomass represents almost an equal amount of water.

        Think of the fresh grass you rake up after mowing your lawn (does anyone still do this?) — heavy fresh grass, if left spread out for the afternoon in the sun, turns into light dry grass as the water returns to the atmosphere.

      • wim and Mike ==> There is a satellite, SMAP, that has begun to measure soil moisture content from space. Produces some interesting graphics, but not a long enough data base yet for serious study.

      • Kip Hansen September 14, 2017 at 8:37 am: “There is a satellite, SMAP, that has begun to measure soil moisture content from space.”

        WR: Thank you Kip for the very interesting link. Unfortunately some months after starting operation one of the instruments of the new satellite failed (radar) and therefore now only maps with lower resolution can be produced: https://www.nasa.gov/press-release/nasa-soil-moisture-radar-ends-operations-mission-science-continues

        But anyway the results of the satellite are and will be very interesting.

      • WR: A simple but important thought: the simple fact that plants evapotranspirate less water at higher CO2 levels means automatically (!) that more water in soils will be available for storage.

    • We have seen an increase of global temperatures of around 1 Deg. C over the last century

      That degree is probably not real. We have biased so much our past temperature records (1900-1979) that a significant part of that degree is probably fictitious. One of the big problems of alarmists was that proxies did not agree with adjusted at pleasure instrumental data: the famous “hide the decline.” In my opinion the global average temperature increase since 1900 is probably no more than ~ 0.6-0.7 °C.

      Sea level is one of the two great climate integrators that answer the question on how is the warming of the world proceeding. There has been a recent spurt of articles trying to accelerate sea level rise by:
      – Adequately selecting a group of tide gauges that show acceleration since 1990.
      – Decreasing past tide gauges sea level measurements through adjustments.
      – Introducing early satellite drift corrections to show acceleration in the satellite data.
      – Producing new sea level reconstructions that show less increase in the past.
      No doubt when they are done we will have the sea level rise acceleration needed to support the CO2 hypothesis.

      If the world is not scared enough by the rate of change, the rate of change will be inflated as much as needed.

      • Javier ==> In my two recent light-hearted posts on Climate Science Double Speak the data emerged that the average temperature of the Earth is still about 15 degrees C — just as it has always been in modern times.

        That’s really why the current scare metric is the non-physical Temperature Anomaly.

        I do agree with you on the nonsense being done with the SLR metrics — same ol trying to get experimental results to agree with pre-determined conclusions == ” the consensus may well simply be an accurate measure of the prevailing bias in the field. “

    • Mike ……………..Another BIG unknown is the rate of change of the volume of the ocean basins resulting from tectonics, i.e. subsidence of cooling oceanic lithosphere, submarine volcanism, compaction of marine sediment, etc.

      • But Peter, they must know as they adjust SL rise up by .3 km+@ a year to account for basin increase.
        ( Everyday evidence of clear bias, as SL is SL, and you cannot call a factor that theoretically moderates SL down, an increase in SL unless you have an agenda.

    • There’s also been bacteria found nearly 2 miles into the crust. So we have biomass covering the surface and down, at least, 2 miles (not saying every cubic area is covered lol).

      This planet is literal Gaia.

  14. So the Southern Coast of California is subject to storm surges…. if I understand you correctly. When was the last storm surge in that area that flooded anyplace but Sunset Beach (almost a yearly ritual)? When was the last hurricane in Southern California? Tsunami of any significance? Floods in SoCal are overtaxed and debris plugged local drainage systems that clear within hours. “Storm surges” are big waves that temporarily erode beaches and get Pacific Coast Highway wet in a few locations. Bad example.

    • markl ==> I have used LA as an example simply because it is home to 18 million people. It is typical of American coastal cities in that some areas are quite safe from SLR and Storm Surge flooding, and others are at imminent risk of flooding even from fairly minor storm surges — as you point out, Sunset Beach floods when there’s a heavy fog.

      Where geography is protective, and planning has been reasonable, the threat of simple sea level rise and expected storm surges (based on past history) is minimal to non-existent.

      Where men have been foolish and greedy, building where the should not have, thousands of homes are at risk from today’s tides and today’s storm surges. a Pacific Hurricane backing storm surge up into the bay of Los Angeles would leave most of the city unscathed (heavy rains would flood some streets, though LA has extensive and very effective drainage canals) but the even just the areas shown flooded by six feet of water above MHHW represent literally thousands of homes..

      Purposefully selecting examples that are extremes is called cherry-picking — not a scientific approach.

      There is nothing that I am trying to prove one way or the other — just trying to present a reality.

      • Understand your explanation but it didn’t answer my questions. I’ve lived in SoCal near the ocean over half a century and never experienced flooding from storm surges (Sunset Beach notwithstanding) and in that time we’ve had some BIG storms. It’s like using Los Angeles as an example for snow damage :-) But I’m nit picking…. your message is clear and accurate for many locations that experience storm surges like the Gulf and East Coast.

    • markl ==> I am having trouble understanding your point. This essay is about Sea Level Rise, and the associated dangers of building too close to sea level which includes storm surge (any time the weather pushes water up against the coast raising apparent local sea level).

      This essay is not about the flooding caused by heavy rains in the LA Basin — which are another matter and the reason for an extensive system of storm drain canals (I supplied a link somewhere in comments).

      Hurricanes do not generally hit the Southern California Coast — but this essay is not about hurricanes. The wiki has a list of California hurricanes.

      • “…I am having trouble understanding your point….” Sorry, not trying to be obtuse. My point is you used an example that won’t materialize. Storm surge, like snow, in the area you mapped is almost non existent. Maybe I missed your point?

      • Markl ==> The simple point is that these areas (and only these areas) are already in harm’s way because of their low elevation very near MHHW, lower the Maximum (historic) highest ever water, and already flood with existing conditions — which will only get worse as the sea slowly rises. They are not yet at the point Miami Beach finds itself — which I characterized as “ought to preemptively be declared a disaster zone”. But there is little doubt that they will flood and will be inundated over the course of the next few decades, sooner or later, a Pacific storm will backup on the coast off San Pedro or Huntington and bring five to six feet of water with it.

        These low-lying areas are not threatened by Sea Level Rise — just threaten by the sea even at its current level.

        The second point is that no reasonably expected amount of SLR (in this or the next century) will adversely affect any other part of the Greater Los Angeles megapolis — contrary to alarmists constant drumbeat of stories and studies about SLR.

    • Storm surge here in the W. Coast is typically on the order of inches, maybe a foot at most. Obviously tropical systems are too weak to cause them, by they time they reach our latitude as relics. It’s the larger winter systems that will bring a surge. The “perfect storm” is when there is a King Tide plus a surge plus lots of rain. I witnessed bad flooding under this scenario in Milpitas (a suburb up here in the Bay Area) back during the El Nino winter of ’97-’98.

    • Marlow ==> Thanks for this link — for the other readers, here is a cropped image of a “hurricane-proof beach house”:

      • That is common on the NJ coast today but not so extreme in elevation. The living quarters start at the second floor typically.

      • Cat ==> Yes, that’s also what I’ve usually seen in the Carolinas. I was surprised by the three story model in the link, so shared it.

      • cerescokid ==> i grew up in LA and remember the still operating oil fields as great places to play — lots of open space, interesting stuff laying around, absolutely forbidden territory (made it more fun to be there). Oil fields were also locations for horse stables and riding trails – one episode there left me unable to dance at my Senior Prom.

    • The Dutch had more sense and ability centuries ago than the professional planners have today.

      Not exactly. The key difference is that all this land was privately owned, and the protection was not done by a bureaucratic government using public money.

      In general, better results are obtained by private capital with a specific objective: This is one of the great fallacies of Socialism, that public ownership leads to better results.

      • Leo Smith September 14, 2017 at 2:49 am: “Not exactly. The key difference is that all this land was privately owned, and the protection was not done by a bureaucratic government using public money”

        WR: The Dutch had (and still have) “Waterschappen” which were rather small scale semi government institutions. The board is elected by the local / regional people they are working for. The first ‘waterschap’ was established in the year 1255, so waterschappen know a long development. In 1950 there were still 2600 waterschappen in our small country. Right now, because of efficiency there are only 26 left, but the direct control by the people is not changed. The waterschappen have the right to levy tax upon the people they are protecting.

        For protection agains the water and for the cleaning of my wastewater I all together pay a 180 euro for my household, some 215 dollar. That’s what a long term investment in safety (and cleaning) costs after years. Protection is a very long term investment that (in my opinion) is much cheaper than the disturbance of daily life, the destruction of investments plus negative effects on the economy – that is not working for days or more. Not to talk about the stress millions of people have.

        I am feeling quite safe behind our dikes. Most of my life I lived some meters (up to 4.5 meters) below sea level. Like millions of us do. Without any problem.

    • The Dutch had to drown in scores to produce that sense and ability. Exactly the same others are doing now. Every prudent construction code has been introduced as a result of some previous catastrophe. That’s how we learn.

      • You are right, Javier. In the Netherlands the Afsluitdijk was built after the storm surge of 1916, the waterworks in the river Schelde estuary (the ‘Deltaplan’) were built after the storm surge of 1953. But times have changed. I have the impression that in the Netherlands loss of live by drowning is now better correlated with nice swimming weather than with storm surges.

  15. The global average rate of coastal sea-level rise is about 1½ mm/year (6 inches per century).

    What’s more, sea-level isn’t rising everywhere. At about 20% of tide-gauge locations sea-level is falling.

    You might think that in places where sea-level is rising, even at a slow pace, SLR must eventually cause increases in flooding. But that isn’t necessarily true, because other coastal processes often keep up with or even outpace SLR.

    For instance, studies show that coral atolls are remarkably resilient in the face of sea-level change, and the coral growth rate can easily keep up with such a minuscule rate of sea-level rise. Here’s a paper:

    http://geology.gsapubs.org/content/early/2015/04/27/G36555.1.abstract

    Silt, dust & vegetation buildup can often exceed 1½ mm/year. In the tropics, peat can sometimes accumulate at over 10mm/year.

    Higher CO2 levels help salt marshes cope with rising sea-level, because the CO2 helps the vegetation grow faster. Here’s an article:

    https://phys.org/news/2015-12-coastal-marshes-resilient-sea-level-previously.html

    Here’s an excerpt:

    “…The research, published this month in the Proceedings of the National Academy of Sciences, shows that the significant boost in marsh plant productivity associated with elevated levels of atmospheric carbon dioxide will allow marshes to trap more sediment and create more organic soil.
    This, in turn, will result in increased rates of accretion that will allow marshes to keep up with rising sea levels and may increase the thresholds for marsh drowning by up to 60 percent.”

    Translation:
    more CO2 emissions = better for coasts
    less CO2 emissions = worse for coasts

    I know of only one location in the last century in which SLR had a severe impact on a coastal community. I give you the sea-level measurement record at Seward, Alaska:

    Seward got a full meter of SLR, in just one day. (But, of course, the Great Alaska Earthquake had nothing to do with anthropogenic climate change.)

    • Daveburton and David M ==> Joking aside, in the next part of this series I will cover this subject of the relationship between the land and the sea surface, each being in motion, closer to or away from, the center of the Earth.

      As Burton points out, rivers carry sediments to add to deltas, storms add or take away sand from beaches, coral atolls build themselves, continents move up down, marshes are land makers — all these processes, some intolerably slow, and other frighteningly fast change what we know as Relative (Local) Sea level.

  16. Kip, have you had any angry rebuttals from the alarmists? I can’t see any posts here. Has your evidence (rare in much of climate science) silenced them?

    • Kelvin ==> Climate Change/Sea Level Rise is a Modern Scientific Controversy

      “This means that great care must be taken in reading and interpreting new studies and especially media coverage of the topic (including this essay) — bias and advocacy are rampant, opposing forces are firing repeated salvos at one another in the journals and in the press and the consensus may well simply be an accurate measure of the prevailing bias in the field. (h/t John Ioannidis)”

      It also mean that for the participants in the Science War — those that the two far edges of opinion or position — there is no convincing by evidence. This last observation is true in ALL science wars. See my series here.

  17. At Cape Hangklip, East of False Bay in South Africa, I have walked on what was seabed which has coral formations embedded in it. It is probably about 10 feet above S.L.

  18. I read a few years ago that the sea “level” in the middle of the Indian Ocean was about 80′ lower than the edges and assumed that this was because of the vigorous ocean circulation, rather like stirring water in a bucket. So what might happen if this circulation slowed down a little? Might it cause the sea level at the ocean edges to rise and be a possible cause for the flooding in low lying areas like Bangladesh?

    • Sara — I think that current thinking — supported by some satellite measurements — is that the low sea levels in the central Indian Ocean are (mostly?) caused by uneven distribution of mass within the Earth. i.e. gravity is a little stronger there than elsewhere because there is a bit more mass than elsewhere between the water surface and the center of the Earth.

      I could easily be wrong about that.

    • Sara ==> The sea is lumpy bumpy — on a grand scale, not flat at all. It is also not like a bathtub — adding water at one point does not raise the level everywhere evenly.

      Not a lot is know about the whys and how-it-works. The GRACE satellites are trying to figure out the gravity component.

      About 10% of Bangladesh is a sea level river delta — covered with the homes of a million people. In 1991 hundreds of thousands of people lost their lives in a single storm.

  19. “Where the greed of developers and lack of foresight by city planners (under the assumption that there was anyone doing city planning) has allowed thousands upon thousands of homes to be built in harm’s way in Sunset Beach, Huntington Beach, Seal Beach and other low-lying beach communities at the southern edges of the LA Basin.”

    This is an incomplete sentence. What are you trying to say here?

    • blcjr ==> My wife too is an English major….usually edits for me but was out of town yesterday and failed in her proof-reading duty (see how I managed to blame her?)

      Try running the two sentences together at this point “and other low-lying beach communities at the southern edges of the LA Basin, these homes stand at risk….”

      I love readers who actually read carefully enough to catch these things for me…..

  20. Miami is sinking! Please use DGPS to assess this.
    For other places, look at 200 to 300+ year old Admiralty charts to see what has really changed because of “SLR”.

  21. Nicely done. Wouldn’t it be great if all the MSM articles about SLR were as measured, informative and circumspect as this one, instead of the usual hysterical propaganda pieces. But then true education doesn’t always sell newspapers.

    • …kid ==> Thank you. Said before but worth repeating:
      “Sea Level Rise is an ongoing Scientific Controversy. This means that great care must be taken in reading and interpreting new studies and especially media coverage of the topic (including this essay) — bias and advocacy are rampant, opposing forces are firing repeated salvos at one another in the journals and in the press and the consensus may well simply be an accurate measure of the prevailing bias in the field. “

  22. Excellent article Kip. You might have mentioned that the area on the extreme West of your map near the words “Docks and Warehouses” is protected by large berms and is stabilized against subsidence (primarily) caused by petroleum extraction. They pump water into the strata under the area to prevent further subsidence.

    I think San Diego — 100 miles to the South might have been an even better example. Unlike LA which built outward from an interior location on the Los Angeles River and developed its port and ocean fronts in the 20th century as an afterthought. San Diego grew around it’s excellent natural harbor. Like many seaports around the world downtown SD is built on a lowland site about 2-3 meters above the ocean. It also has communities — Imperial Beach and Coronado — built on a barrier island. That’s common on the East and Gulf coasts, but a rarity on the West Coast.

    An additional point. In California, coastal housing probably not only should be built to Florida construction codes to protect against tropical cyclones, but needs to be built to survive major earthquakes. My impression is that enforces quite different requirements on architectural design

    One other factor that is difficult to quantify. Many low lying areas in SoCal are protected from the Pacific waves by wide sandy beaches. The sand migrates North to South over time. Much of it eventually disappears into submarine canyons. All well and good. But upstream flood control efforts are purportedly cutting off the sediment flows that provide new sand to the beaches. Probably not a short term problem, but long term, it could be a problem. While some of Southern California’s sea cliffs are well consolidated sediment, many are pretty much just big dirt piles. Without the protective beaches, major storms will probably erode those cliffs quite severely.

    • Don K ==> Thanks for the additional information. I haven’t been down to the San Pedro docks since the early 1970s when I was helping refit an old WWII sub-chaser.

      I couldn’t locate the berms you speak of on the two-dimensional Google satellite view. Can you tell me exactly where they are?

      BTW, I picked Los Angeles as the largest megapolis on the West Coast — then did the SLR research on it. Not really proper to “pick” a “good example” of one’s preconceived conclusion — that’s what Climate Scientists do :-). I just took the data as it came out —

  23. Has anyone ever attributed SLR to aquifer depletion? I am not too sure on where the human population gets its water, or whether aquifers are even a significant water source. I know it’s an issue in the (former) Great American Desert, or as the Progressives now call it, Fly-Over Country.

    • Wu Nee ==> Yes, there is a lot of talk about aquifer pumping out adding to the surface water budget and thus to rising seas — but, as I will eventually discuss later in this series of essays, the sea level data set doesn’t show this — or really any (much) modern contribution of this, or glacier melt, or Greenland ice sheet melt, or anything else. It has been mostly just “business as usual” for the long spookily steady rise in absolute sea level for as long as we have records.

    • Wu – The IPCC has looked at contributions from aquifers. They say the numbers are hazy, the amount is fairly small compared to other source of SLR — which i dominated by thermal expansion of the oceans as they slowly warm.. And to date it’s probably largely offset by the sequester of water on land in new reservoirs.

  24. Still not sure I buy the 12 inch sea level rise, per century. Having looked at cliff undercuts all over the Med, they appear to be on the present sea level (no tides to worry about in the Med). And judging by the thickness of the stalactites, the cliff faces are over 500 years old. And while I was in the Philipines last year, I noted large undercuts on the low-tide sea level there too.

  25. It would appear that sea level will either go up or down as temperatures only go up or down. There is no stable level only the appearance within a persons lifetime. Either way the the shore line will be somewhere else in future. Looking at all climate data there are NO horizontal lines unless time scales are reduced sufficiently to reduce detail.

  26. Sea rise early in the interglacial period drowned HUNDREDS of cities, river basins,roads,mines yet we continue to hug the ocean shores today.

    Drowned Cities

    ” Gradually rising seas

    For 4,000 years, the world’s sea level has been inching up.

    This has been caused by

    (a) the melting of the post-Flood ice and

    (b) the gradual evaporation or outflow of inland basins to the sea.

    The gradual rise of the oceans is thus another clear relic of the Deluge. Flood waters left behind on the land, in the form of ice or inland lakes, have been gradually returning to the oceans. The result has been not only a drying out of the land, but a corresponding rise in sea level.

    The Hadji Ahmed map of 1559, whose original source dates back thousands of years, shows a landbridge between Siberia and Alaska, which existed when the original map was drawn. If the ocean between these two land masses were lowered 100 feet today, there would be a dry-land path between them.

    According to some oceanographers and geologists, the ocean level may have been as much as 500 feet lower than today.

    Ireland was connected with England; the North Sea was a great plain; Italy was joined to Africa, and exposed land cut the Mediterranean into two lakes.

    Since then, the rising seas have engulfed coastal land and islands, turning isthmuses into straits and large islands into underwater plateaus.

    Along many of the world’s shorelines are lost islands, now deep below the sea, with remains of cities, palaces and temples.”

    a lot more here:

    http://www.beforeus.com/drowned.html

  27. At a talk at SIO some years ago, an avowed AGW alarmist warned the public about the imminent dangers of SLR. At its conclusion, I commented to the effect that I won’t begin to act on it until the UC real-estate division–who have masterfully acquired large acreages of prime coastal property throughout the state–would announce the sale of the lower SIO campus at 10 cents to the La Jolla dollar. I’m still waiting…

  28. Kip Hansen, I would greatly like to fully understand how sea level rise is measure/calculated, as you stated you would be writing an article about that topic soon. How do I get a copy of that article?

    • Dale ==> How we measure Sea Level and SLR will be the main topic of Part 2 or 3 of this series. You can just leave a comment to the one you want …. or email me at my first name at the domain i4 decimal net when the time comes. Be glad to send you a .pdf of the essay once it is written.

  29. Harson sez:
    “Given that the average rise of the seas over the last century or so (the total length of our dependable instrumental record) has been about 8 to 12 inches …”

    6 inches, not 8 to 12 inches !

    HOW CAN WE TRUST ANYTHING ELSE YOU WRITE
    if you can’t get the most basic fact about sea level rise correct?

    I’ve got an article on the subject you need to read: Sea Level 101:
    http://www.elOnionBloggle.blogspot.com

    • Richard ==> You are welcome to comment — but not to troll. This means abiding by the WUWT policy on commenting and its generalized requirement that participants here engage in civil conversation.

      There is no single correct number for the amount of sea level rise over the last 100-150 years. Scientific opinions on the magnitude of Sea Level Rise since the late 1800, about the start of the measurement records, vary from 6 inches to 15 inches, with the most common range given as 8 to 12 inches, in many cases simply “about a foot”.

      • Harson
        Do you character attack anyone who disagrees with you as “trolling”?

        In a prior comment, you said you hadn’t heard from me, so thought I might have died.

        Talk about rude!

        I use my real name.

        I posted the quote in your article that I disagreed with.

        I posted the right (conservative) answer of a 6″ sea level rise in past century.

        A century is 100 years — not “100-150 years” as you wrote in your latest comment.

        Your 8″ to 12″ is on the high end of the estimates, for no good reason.

        You should have used 4″ to 12′ as a range.

        The warmunists have been pushing up the range in recent years, using arbitrary adjustments, and questionable satellite measurements ( questionable because they show so much more sea level rise than the tide gages that were used for most of the past 100 years).

        I provided a link to my article on sea level rise posted on my climate blog today, which includes some comments on why satellite data may overstate sea level rise.

      • Richard ==> My patience is limited, and you have just lost the right to receive replies from me. To earn that privilege back, you must only engage in civil and constructive comments here.

      • Harson,
        Your “patience is limited” to people who agree with you !
        Your patience with disagreements is near zero.

        I challenge you to name any current scientific consensus’ you agree with.

        Based on your articles here, you believe every scientific consensus is wrong.

        And there is always some recent contradictory study that you think is definitive, and proves the consensus is wrong. That pattern is so consistent I recognize it as your bias.

        You should post as Kip “the consensus is always wrong” Harson,
        so people understand your bias before they start reading anything you write

      • Gentlemen: the difference between your estimates is a mere two inches in a century, or 0.5 mm/yr. Is that really worth getting hot and bothered over?

        What’s more 60% (0.3 mm/yr) of the difference between 6″/century and the often claimed 8″/century rate is due to the addition, in the larger estimates, of Peltier’s 0.3 mm/yr estimate of the effect of the ongoing sinking of the ocean floor, in response to loading from meltwater from the last deglaciation. Most alarmist climate scientists add that adjustment, which slightly inflates their reported rates of sea-level rise.

        (I don’t agree with that. Adding the adjustment makes sense if you’re trying to calculate water mass changes, but it is not correct for coastal planning, the sum isn’t actually “sea-level rise.” When that adjustment is added to a measured sea-level trend the sum is really an estimate of what the sea-level trend would be, were it not for the sinking of the ocean floor.)

        When Peltier’s 0.3 mm/yr adjustment is taken into account, it leaves just 0.2 mm/yr (0.8″ per century) true difference between Richard’s number and the low end of Kip’s range. Can’t we all agree that’s not enough to fret about?

        In fact, Richard’s blog article says, “The precise rates of change are an open question,” which sounds agreement with what Kip wrote, above: “There is no single correct number for the amount of sea level rise over the last 100-150 years.”

        As it happens, I agree with Richard’s estimate (6″ per century) of the “global average,” but, truly, y’all are not that far apart.

        Most places are not “average,” anyhow. At about 1/3 of the world’s tide gauges, vertical land motion has a greater effect on the local sea-level trend than does global sea-level rise.

        The main practical use of sea-level trend analyses is for coastal planning. What difference does it make to, for example, Vaasa, Finland, whether “global mean sea-level rise” is 1 mm/yr, 2 mm/yr, or 3 mm/yr? Since sea-level rise has been approximately linear for nine decades, and has not been noticeably affected by GHG emissions and global warming, the best prediction for sea level in the future is simply a linear projection of the history of sea level at the same location in the past.

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