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San Francisco To Drown By 2100

March 9, 2018

By Paul Homewood




The ground around San Francisco Bay is sinking to meet the rising sea, another reason for Bay Area residents to worry about the impact of climate change on their region.

A new report suggests that sinking land, known as land subsidence, will increase the potential reach and damage of flooding in the Bay Area, submerging a larger portion of the region by the year 2100 than previously estimated.

Subsidence can be caused by groundwater pumping, which can act to “deflate” the ground above it or the gradual compacting of landfill — when lands are filled in an effort to create solid ground to build upon.

The authors of the report — Manoochehr Shirzaei, a professor at Arizona State University and Roland Bürgmann, a professor at University of California, Berkeley — have combined land elevation data with rising sea level projections. And they are now challenging the current flood threat projections as too conservative.

The authors hope that their new findings will help cities and agencies produce more accurate hazard maps, updating the extent of affected areas.

Under the new projections, San Francisco International Airport could see half of its runways submerged by the year 2100. Original estimates that did not include land subsidence were much lower. Other areas around the Bay that have been built on engineered landfill, like parts of Foster City and Treasure Island, are particularly vulnerable to the dual impact of subsidence and sea level rise.

Scientists have long tracked the effects of global warming on the planet’s water levels. A recent study of 25 years of satellite data pointed to climate change as a cause for the acceleration of rising sea levels, making previous estimates unreliable.

“It’s a very well-known problem, but we really don’t know how fast it’s going to be in the second half of the 21st century. This is a projection,” Dr. Shirzaei said.



Subsidence may be a very real problem, but absolute sea level rise is not.

Sea levels at San Francisco have been rising records began in the 1850s, at an average rate of 1.96mm/yr:



The rate of rise has actually been decelerating since 1970, and the fastest rise occurred 1920 and 1970:



San Francisco airport is 13 ft above MSL on average, so at that rate it will be underwater in 2000 years time.

Meanwhile little seems to have changed since 1927.



San Francisco may have problems with subsidence, but this is an engineering problem, which cannot be solved with any number of wind farms.

  1. Gamecock permalink
    March 9, 2018 12:26 pm

    ‘Under the new projections, San Francisco International Airport could see half of its runways submerged by the year 2100.’

    Because San Franciscans are too stupid to bring in landfill and repave the runways.

    • Le goof permalink
      March 9, 2018 12:41 pm

      1. Due to runway thickness in the “touchdown zones”, usually first 3,000ft at each end, probably much less disruptive and expensive to build a “sustainable” (definition de jour) seawall.
      Beneficiaries would be all the construction/engineering industries involved. Exacerbate subsidence rate?
      More “studies “!
      >return to 1<

    • catweazle666 permalink
      March 11, 2018 10:43 pm

      “‘Under the new projections, San Francisco International Airport could see half of its runways submerged by the year 2100.’”

      Always supposing the san Andreas hasn’t let go and dumped the whole of the Left Coast into the Pacific Ocean.

  2. charles wardrop permalink
    March 9, 2018 12:28 pm

    Bravo to you, Mr Homewood, for the clarifying info.

  3. Jack Broughton permalink
    March 9, 2018 12:54 pm

    Professors Henny-Penny and Ducky-Lucky: where’s Foxy-Loxy when you need him????

  4. March 9, 2018 1:00 pm

    It is a sad thing when the AGW Meme continually inserts itself into the science mindset.

    The object of this report is surely very valid; as it has impact on the engineering policies required to mitigate observed subsidence.
    Bringing the global sea level factor into the equation was necessary; but should have been clearly reported as of minimal influence and best ignored.

    Perhaps the mincing words of Dr. Shirzaei at the end were required in order to obtain publication.

    In consequence the false threat of climate sea inundation hovers over and detracts from the work done in the report and once more sullies the reputation of the scientists.

    • Mike Jackson permalink
      March 9, 2018 1:32 pm

      Well said! And in this area, as in all too many others, actively prevents action to mitigate, alleviate, prevent … because it’s all “Climate Change” which “we” can do nothing about except by giving up our 21st century lifestyle.

      Correction — which we can only do something about by *you* giving up *your* 21st century lifestyle.

  5. March 9, 2018 1:29 pm

    If the highly unlikely should happen and San Francisco should “drown”, it might be a boon. Here is what happens to a jewel city when you allow the left (Democrats) to run it for any length of time. They turn it into a third world slum. It might wash the feces and needles away. Pictures of Detroit looks like Europe following WWII.

  6. Broadlands permalink
    March 9, 2018 1:39 pm

    It’s amazing what a little added CO2 can do…cause the land to subside and the oceans to rise….requiring more funding for research… to be sure?

    • March 9, 2018 3:51 pm

      More studies? But I thought it was settled science now. Why do they keep doing studies if it’s all settled?

  7. March 9, 2018 2:13 pm

    These days, everything is always worse “than previously expected”, proving that they were wrong in the past, so why should anybody think they will be right this time?

  8. TomL permalink
    March 9, 2018 2:17 pm

    San Francisco bay is surrounded on all sides by high, steep hills and receives all the runoff from the west slope of the Sierra Nevada. In spite of the large influx of sediment an area of several hundred square miles manages to remain below sea level. The Bay also happens to sit right on top of an active transform tectonic plate boundary.
    Do you suppose vertical tectonic motion unrelated to fossil fuels might be a factor?

  9. March 9, 2018 2:34 pm

    I wonder what the Dutch would do…

    • Stuart Brown permalink
      March 9, 2018 2:46 pm

      Beat me too it and way more succinctly!

  10. Stuart Brown permalink
    March 9, 2018 2:45 pm

    ‘San Francisco may have problems with subsidence, but this is an engineering problem, which cannot be solved with any number of wind farms.’

    Maybe. The Dutch drained vast areas with wind pumps. Beemster is 72km2, Schermer 64km2. But this might be the limit of 1600s technology.

    You can bet, however, that money could be found to protect the San Francisco airport. By contrast, Schiphol airport is 4 metres below sea level and was built in a drained lake. It’s a major international hub, catering for nearly 70 million passengers last year, so slightly bigger than San Francisco airport, but not by much.

    Now, the lake was actually drained in just 3 years from 1849 using steam engines, but the arguments about the unreliability of steam vs tried and tested wind pumps apparently raged for years.

    San Francisco Bay is 10 times the size Haarlemmermeer was, but most is not much deeper. Give the Dutch the engineering problem and you could be growing crops in the middle by 2050 easy, let alone 2100.

    Shame about all those seabirds, crabs, halibut etc though.

  11. Athelstan permalink
    March 9, 2018 2:51 pm

    “suggests that sinking land, known as land subsidence”

    Are they kidding, or do they (NYT) condescendingly view the American public the same as here with NHS England/HMG UK – ie, we’re all a tad thick?


    is it a wind up?

    What would they know, mind you according to ‘the Al Goreacle’, NYT will be “6-7 metres under by the middle of this century” whatev.

    And besides when the big one comes, we don’t know when but we sure know (geologically speaking) it will be soon, what’s a millimetre or two between seaboards Pacific V Atlantic?

  12. Harald Martin permalink
    March 9, 2018 4:05 pm

    San Francisco underwater? Is there some way we could speed that up?

    • John F. Hultquist permalink
      March 10, 2018 3:41 am

      Good that I read the comments before writing.
      So, I’ll just 2nd HM’s thought.

    • March 12, 2018 8:35 pm

      Harald I promise I will do my bit. I’m going to jump in my SUV now and drive to the corner takeaway for a cheeseburger.

  13. John Fuller permalink
    March 9, 2018 4:08 pm

    It doesn’t surprise me that parts of San Francisco have problems with subsidence. Further south near Bakersfield, the Belridge oil field has very well known compaction and subsidence due to the extremely porous diatomite reservoir. I’m not sure if these same sediments extend into the San Francisco Bay area. But if there has been water extraction in similar formations the loss of pressure could cause dramatic subsidence above; in the order of centimetres, rather than millimetres, per year. Far more than the sea level rise discussed above. If this is the case then I’d agree with Paul, this is an engineering problem, not a sea level rise problem.

  14. LOL@Klimate Katastrophe Kooks permalink
    March 10, 2018 3:55 am

    If you drive around the perimeter road at SFO, you’ll note in the northeast corner (at the northern end of the 19R runway) that the wall there already has water seeping through at its base… not due to sea level rise, but because the land is subsiding.

    If you go underneath the ITB building, you can see that the land has subsided in some places by several inches, pulling away from the pilings holding up the building.

  15. LOL@Klimate Katastrophe Kooks permalink
    March 10, 2018 4:27 am

    Taking a look at the tide gauge for SFO:

    And exporting the data to a .csv file, then importing it into LibreOffice Calc, then discarding the years prior to 1854 (since those years don’t have trend data), then summing the Monthly MSL and Linear Trend columns shows the following:

    Monthly MSL: -200.029 mm
    Linear Trend: -198.892 mm

    How, then, do they show a rising trend in their chart?

    Doing away with data prior to 1910 (when there was an Apparent Datum Shift), we get:
    Monthly MSL: -86.717 mm
    Linear Trend: -84.17 mm

    How, then, do they show a rising trend in their chart?

  16. LOL@Klimate Katastrophe Kooks permalink
    March 10, 2018 4:37 am

    Looking at Jan 1968 to present (approximately the last 50 years), we get:
    Monthly MSL:-4.87 mm
    Linear Trend: -4.097 mm

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