Claim: Odds of storm waters overflowing Manhattan seawall up 20-fold, new study shows

I think I know a practical reason for this, which I’ll cover in a post later, but I’d like readers to weigh in first.

From AGU:

Newfound rise of storm tides by almost a foot since 1844 adds to risk from sea-level rise

WASHINGTON, D.C. — Maximum water levels in New York harbor during major storms have risen by nearly two and a half feet since the mid-1800s, making the chances of water overtopping the Manhattan seawall now at least 20 times greater than they were 170 years ago, according to a new study. Whereas sea-level rise, which is occurring globally, has raised water levels along New York harbor by nearly a foot and a half since the mid-19th century, the research shows that the maximum height of the city’s “once-in-10-years” storm tide has grown additionally by almost a foot in that same period.

The newly recognized storm-tide increase means that New York is at risk of more frequent and extensive flooding than was expected due to sea-level rise alone, said Stefan Talke, an assistant professor of civil and environmental engineering at Portland State University in Portland, Ore. He is lead author of the new study accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union. The research also confirms that the New York harbor storm tide produced by Hurricane Sandy was the largest since at least 1821.

water level data

Tide gauge data analyzed in the study show that a major, “10-year” storm hitting New York City today causes bigger storm tides and potentially more damage than the identical storm would have in the mid-1800s. Specifically, Talke explained, there’s a 10 percent chance today that, in any given year, a storm tide in New York harbor will reach a maximum height of nearly two meters (about six and a half feet), the so-called “10-year storm.” In the mid-19th century, however, that maximum height was about 1.7 meters (about 5.6 feet), or nearly a foot lower than it is today, according to tide gauge data going back to 1844, he noted.

“What we are finding is that the 10-year storm tide of your great-, great-grandparents is not the same as the 10-year storm tide of today,” Talke said.

To get the data used in the study, Talke and a graduate student photographed hundreds of pages of handwritten hourly and daily tide gauge data going back to 1844 that is stored at the U.S. National Archives in College Park, Md. Back in Portland, Talke and his students entered the data into spreadsheets and adjusted the data where points were erroneous or missing, including using newspaper accounts of big storms to fill in some of the holes. The researchers then analyzed the data to calculate storm tide levels and look for trends, and compared the information with climate data.

The storm tide is the amount that water levels rise during a storm. It includes both the storm surge – the abnormal rise in water generated by the storm above the sea level – and the predicted astronomical tide. The rise in storm tide outlined in the recent study is in addition to the .44 meter (1.44 foot) rise in local sea level that has occurred since the mid-19th century in New York harbor.

Combining the newly calculated rise in storm tide with the rise in sea level that has taken place since the mid-1800s, the researchers found that today, waters can be expected to overtop the lower Manhattan seawall – 1.75 meters (5.74 feet) high — once every four to five years. In the 19th century, when both sea levels and storm tides were lower, water was expected to overtop the Manhattan seawall only once every 100 to 400 years, according to the paper.

tide graphic

Scientists have studied the question of increasing storm tides in the area before, but none have gone back as far as the current study, Talke said. Hourly storm tide records for New York harbor that are kept by federal agencies, like NOAA, only go back to the 1920s, he said.

In the paper, Talke and his colleagues suggest that the variability in storm tides in New York harbor over the past 170 years could be a result of multiple factors. About half of long-term change could be attributed to decades-long variations in the North Atlantic Oscillation, an irregular fluctuation of atmospheric pressure over the North Atlantic Ocean that has a strong effect on winter weather in Europe, Greenland, northeastern North America, North Africa, and northern Asia.

Longer-term trends could also be influencing the increase in storm tides over the past two centuries, according to the paper. The authors speculate that climate change and increasing global temperatures could be contributing to the increase in storm tides. There could also be local factors, like deepening of shipping channels around New York harbor, that could have affected storm tides in the area over the past 170 years, Talke said.

tide data

The study’s findings may indicate that “storm surges’ interaction with New York harbor has gotten larger so that in addition to sea level rise, the storm surges may have been enhanced,” said Chris Zervas, a scientist at NOAA’s Center for Operational Oceanographic Products and Services in Silver Spring, Md., who was not involved in the study. “For the latter part of the 1900s, [it shows] that the possibility of overtopping the seawall has increased quite a bit in addition” to sea-level rise, he added.

Having this long, continuous set of data enabled the scientists to tease out decades-long cycles and long-term increases that they may not be able to see with shorter data sets, Zervas and Talke said.  Knowing that there has been an increase in storm tides and figuring out why the increase occurred could help scientists better predict what will happen in the coming decades and help cities mitigate future problems, Talke said.

“If it turns out to be a local reason, as has been suggested in some cases, there could be local solutions as well,” Talke said. “In some cases, we may be able to turn back the clock on that a bit.”

notebook sketch

 

 

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71 thoughts on “Claim: Odds of storm waters overflowing Manhattan seawall up 20-fold, new study shows

  1. “Adjusted?” “Filled in?” Use the data you do have, and get back to us. Even a press release not specifying the effect of created “data” on their results is so very far from good science. How would the results have changed without using numbers they did not have? What a travesty…

  2. There is just not enough information. I know the effects of man made flood dangers, by poor dredging (see Britain 2014), having flood control (dikes etc) when at one time seawater would flood wetlands and then recede. This is not to me as a Dutchman a very well written or well based report , but what the heck there just as many people to scare to hell out off in the greater NY area as in all of Holland.

  3. I don’t see much to get worked up about. These days I’m a bit more suspect of “adjustments” to data, but it isn’t anything new or restricted to climate science. And they do use the term “speculate” when discussing links to changing climate, which I think is fair.

    Bottom line, between rising sea levels, subsidence, human changes (dredging & filling) and other factors, the risks associated with storm surges to NYC appears to be increasing. That’s good to know. Tells me NYC would be prudent to build higher sea walls and toughen up their infrastructure to flooding. Doesn’t tell me a thing about climate change.

  4. One nice caveat is that the ‘once every 4 to 5 years’ will be quickly put to the test. Aside it was nice to see that they went back and reviewed records and used data rather than run a model!

  5. The rivers flowing into the harbors and bays of Manhattan bring down tons of silt each year causing a raising of the seafloors and the shallowing is causing waves to be higher with the same back pressure as is seen from winds equal to 150 years ago. More dredging would likely correct some of this. I wonder which “wonder model” these green geniuses used this time?

  6. No valid reference datum (i.e. floating comparison).

    How many times was the pier-post with the tacked-on-ruler adjusted since mid-1800s or did it just ‘sink’ in the mud as the barnacles grew and added weight !

    Epoch fail.
    Ha ha

  7. Once again, cherry-picking and “filling-in-the-blanks” to get what they want, GRANT MONEY for more studies.

    When was the seawall last rebuilt, or is it original?
    Seattle is currently rebuilding their seawall, with no apparent height increase to compensate for the “rising seas” attributed to CAGW.

  8. Whatever the cause, if flooding is likely, then local steps, such as dikes and protecting the subway system, should be taken

  9. My thoughts are what changed have there been downstream of NY’s harbour? Was there low-lying land that stormsurges flooded, that are now concrete walls & wharfs, thus funnelling water higher up into the harbour?

  10. The east coast subsidence is well documented. Build up the sea walls as the piers were in the 1930 s. You are behind schedule.

  11. Most of Manhattan’s current sea front proprty is man-made land fill, consisting of anything at hand, including abandoned hulks and garbage. That such 19th century expedients are now subsiding shouldn’t surprise anyone.

  12. Relatively small sample size, major city built on hodge podge of metamorphic bedrock interleaved with Quarternary and Pleistocene poorly consolidated moraine / moraine outwash / alluvium with all the attendant excavations, tunnels and other disruptions, plus, the well known innate sea level rise due to the long tail of the Great Melt, plus, the innate tectonic subsidence of a Passive Margin slowly moving outward from the mid oceanic spreading center.

  13. krs says:
    April 23, 2014 at 9:53 am

    “Gilligan’s Island. Those poor people,….” – Mathesar

  14. I actually like the idea of at least getting the available tidal data in a usable form. I think notions of local changes in the sea floor from dredging and silting deserve careful attention. Bottom line, how many feet do you need to add to the seawall to establish an acceptable risk? I was reading a little while ago about how the Dutch have reassessed their seawalls and because of potential losses are adding to their flood barriers – not because of Climate Change but the increased wealth and population they are trying to protect.

  15. Self inflicted wounds if true. The entire New York Habour area has been changing due to landfill and siltation. Both will change the height of storm tides at a specific location. The water has to go somewhere.

  16. “…. his students entered the data into spreadsheets and adjusted the data where points were erroneous or missing, including using newspaper accounts of big storms to fill in some of the holes. The researchers then analyzed the data to calculate storm tide levels and look for trends”

    OMG more spreadsheet science for beginners.

    At least they seem to be looking for other causes that kneejerk attribution to AGW.

    I thought subsidence was a significant factor in that region.

  17. Makes you wonder why the UN is spending billions in upgrades to their building in Manhattan when it is just going to be inundated.

  18. 1. Are they still dredging the rivers and channels like they used to or is that now bad and not done anymore because of ecological reasons?

    2. A lot of time islands and ports expand by just shoving earth out and building on it. That will subside with time. I’m guessing a certain amount of the area expanded that way.

    3. What changes have happened in the over all water flow and distribution over the last 200 years? You can’t just change how water flows without consequences. You have to adapt to your changes.

  19. Has anyone taken into account the elastic movement from adding billions and billions of pounds of steel, buildings and people there over the last century?

  20. This is what infrastructure spending is all about: adapting to future needs. This soundsl like at most a call pointing out the obvious.

  21. Degrading Ekman transport. The sinking of land south of New York City (they probably should read Nature or Populat Mechanics.. The newly discovered “rising Greenland” effect. Since Ekman effect makes the center of the atlantic a few feet higher in mid-atlantic than eastern seaboard, and fact that the land is actually sinking….

  22. How long has the Lower Manhattan seawall been there? Is it original or something built on filled land?

  23. When I read these kind of alarmist rising sea level perils, I think about a 1965 Gilligan’s Island episode (season 2, episode 6, title: Quick Before It Sinks). The Professor was measuring the tide levels in their tropical lagoon with bamboo sticks as tide gauges. He became very agitated and alarmed when he realized his “data” from his tide gauge sticks showed their island paradise was rapidly sinking. He proposed all sorts of radical solutions from Arks to building the huts on higher ground in the middle of the night so as not to frighten the women. Only at the end did the Professor realize it was Gilligan who was moving his sticks into deeper water for his crab trap anchors.

    http://www.imdb.com/title/tt1288877/

    Lesson: Professors are easily fooled by their data and preconceived interpretations. The alternative explanation that the sticks were being surreptitiously moved by a 3rd party never occurred to him.

  24. Water Street had its name from something, though I’m sure nobody knows what now. Surely it’s several feet under the river now, given the accelerating sea-level rise since 1900.

  25. If they don’t account for glacial isostatic adjustment (land is like little see-saw with north of new york rising and south sinking) and the don’t account for the Sargasso Sea level changes, it’s worthless.

  26. With regard specifically to NYC storms, did the authors also “adjust” for the increase in paved-over land over the metro area, that is, soil no longer available to absorb storm/rain runoff?

  27. Also, if the Manhattanoids care about their land, they can build a taller seawall (or simply pay higher flood insurance rates). Or maybe they can choose to live more than 6ft above seal level so they avoid the problem entirely. Venice is sinking pretty rapidly (relatively, at least compared with Manhattan) & it still has quite a lot of undrowned people in it. Almost as if there was some mysterious mechanism built into (most*) life forms that stopped them from just standing around gape-mouthed whilst the waters lapped over their heads.

    *non-Alarmist

  28. “There could also be local factors, like deepening of shipping channels around New York harbor, that could have affected storm tides in the area over the past 170 years, Talke said.

    could have? This is THE MAIN REASON.

  29. http://onlinelibrary.wiley.com/doi/10.1029/2007GL030862/abstract

    Gyre-scale atmospheric pressure variations and their relation to 19th and 20th century sea level rise

    Laury Miller1 and Bruce C. Douglas2

    Most of the long tide gauge records in the North Atlantic and North Pacific commonly used to estimate global sea level rise and acceleration display a marked difference in behavior in the late 1800’s – early 1900’s compared to the latter half of the 20th century. The rates of sea level rise tend to be lower in the 19th compared to 20th century. We show this behavior may be related to long-term, gyre-scale surface pressure variations similar to those associated with the Northern Annular Mode. As sea level pressure increases (decreases) at decadal and longer timescales at the centers of the subtropical atmospheric gyres, sea level trends along the eastern margins in each ocean basin decrease (increase). This is not an isostatic response; the scaling between local surface pressure and sea level at interannual and longer timescales is 3 to 6 times greater than expected by that mechanism. Rather, it appears to be the result of large, possibly gyre-scale changes in ocean circulation. Some evidence is also presented indicating slow, ∼2 cm/sec, westward propagation of sea level changes in the Atlantic from the west coast of Europe to the east coast of the U.S. which produce the decadal variability seen there.

    http://www.ocean-sci.net/6/185/2010/os-6-185-2010.pdf

    The gyre-scale circulation of the North Atlantic and sea level at Brest
    P. L. Woodworth1, N. Pouvreau2, and G. Woppelmann3

    “In this paper, we present a similar analysis for the North
    Atlantic to that of Miller and Douglas (2007), but use sea
    level and air pressure records twice as long as those used
    previously. The research has been made possible through
    an immense amount of recent “data archaeology”, wherein
    valuable historical records have been rediscovered and their
    data converted into computer form and quality controlled.”…

    “. However, if the Miller and Douglas (2007) interpretation is on the right lines, then the sea level rise (fall) observed on the eastern boundary will be primarily a consequence of the spin down (up) re- sponse of the gyre to changes in wind stress curl. It follows that it will not then be related primarily to the changes in sea level that occur due to variations in ocean volume, although of course the different contributions to sea level change could be related indirectly through various climate forcings….

    “It is certainly the case that the redistribution of water needs to be considered alongside the many factors responsible for ocean volume change on multi-decadal and century timescales that are included in periodic assessments such as that of Bindoff et al. (2007).”

  30. Tide data contains three components: periodic, secular, and episodic.
    The periodic data can be easily identified with a Fourier analysis. It will have components related to the phase of the moon and to the time of day (phase of the sun). because of the celestial mechanics of the orbits on the earth and moon, this will repeat itself almost exactly every 54 years and 33 days (19,756 days equals 669 synodic months equals 717 anomalistic months).
    Removing this contribution will leave the monotonic secular trend (the VERY long range changes in sea level, averaged over the entire span of the data) and the episodic component due to short-term random variability (such as storms).
    This kind of analysis applied to tidal records for the Atlantic coast should also reveal historical data regarding the Atlantic Multidecadal Oscillation.

  31. Rud Istvan says:
    April 23, 2014 at 10:12 am
    LamontT says:
    April 23, 2014 at 10:23 am
    Stark Dickflüssig says:
    April 23, 2014 at 10:37 am
    Charlie A says:
    April 23, 2014 at 10:33 am
    kenw says:
    April 23, 2014 at 11:11 am
    JDN says:
    April 23, 2014 at 11:06 am

    Several writers have asked about the original shoreline across the south tip of Manhattan, others about the fill and dredging that has gone on.

    Above link is to a reliable map showing why this simplistic effort is doomed to merely re-create hysteria and hype. Which IS, after all, its intended purpose.

    But, land movement MUST be specifically and explicitly accounted for: With the baseline elevation, and the continued re-calibration of alignment of that baseline established. Where is Zero?
    Where WAS Zero, and at what time was “Zero” established ?
    How has the land moved with respect to that “Zero”?
    How has Sea level moved with respect to “Zero”?

  32. Upon this infilled estuary We will build a city?
    The management of this papers data duplicates the human management of the harbour.
    I wonder what sea level rise would result from tossing the UN buildings and staff into the East River?

  33. john robertson says:
    April 23, 2014 at 12:05 pm
    ……
    I wonder what sea level rise would result from tossing the UN buildings and staff into the East River?

    Zero. As they are unnatural, water shall surely reject them. The Standard Test for Witchcraft states this plainly..

  34. They actually claimed we should see the sea wall breeched every 4-5 years. If 10 years from now a storm surge doesn’t breech the wall what will the excuses be? WUWT already has a list of things CAGW causes, now how about starting a list of excuses for failed predictions.

  35. Nice job everyone! It didn’t take long for those posting here to see the problem, even without the help of “Major Domo”:))

    It is amazing that they never considered the land holding the tide gauges might move! Perhaps in Portland they are back to Aristotles Geocentric, earth where the natural state of things is at rest.

  36. I seem to recall reading that there used to be large oyster reefs in New York Harbor and these reefs helped to dissipate the energy of a storm surge. Sadly, the reefs are gone now – oysters on the half-shell are my favorites.

  37. timg56 says:

    April 23, 2014 at 9:41 am
    ===
    Yes. No dissent.
    Local or regional effects – which can and should be mitigated.

    Auto

  38. Hurricane Flashback: The Great New York Storm of 1821

    September 3 marks the 190th anniversary of the Hurricane of 1821, which saw flooding and destruction in the growing metropolis. In less than an hour a thirteen-foot storm surge deluged the city, swallowing everything below Canal Street. The Battery was particularly devastated, docks were destroyed, and ships were swept onto streets. Further uptown, a bridge that connected Harlem to Ward’s Island was washed away and somewhere in Chinatown, the East River likely met the Hudson. “New Yorkers were lucky,” writes Bruce Parker in The Power of the Sea: Tsunamis, Storm Surges, Rogue Waves, and Our Quest to Predict Disasters. “The hurricane hit at low tide.“

    http://stevengoddard.wordpress.com/2013/09/05/1821-new-york-hurricane-hit-at-low-tide/

  39. Alarmists are simply inflexible and cowards.
    Everything has to stay as it is and any change makes them fear the worst.

    Come on guys, man up, get a life.
    The sky is not falling all the time. It’s not dangerous out there in the real world.

    But I agree, you shouldn’t have kids and grandkids.

  40. As others have said they need to account for subsistence and moon phase, as well as compare infilled results to non-infilled results.

  41. Those of us with a bit more experience in these matters know the value of marshes, wetlands, tide pools and other such features that have surely been eliminated over time in NYC.

    Houston remembers Ike.

  42. I saw a remarkable thing one clear sunny late autumn day some 20 years ago. I am not sure which bridge it was spanning the Hudson river , I am thinking the Bear Mountain Bridge about 25 miles north of Manhattan. I saw what appeared to be a huge vertical fissure running up the west face of the mountain cliffs. These fissures had many horizontal steel cables of the sort used for major suspension bridges bolted with enormous iron pins to either side of the fissure. Again this was some time ago, but I remember thinking to myself “Holy Sht, Manhattan must be pulling on the land mass all the way up here!” I will be very pleased if anyone else has seen this construct, or was I seeing things…..

  43. “In the mid-19th century, however, that maximum height was about 1.7 meters (about 5.6 feet), or nearly a foot lower than it is today, according to tide gauge data going back to 1844, he noted.”

    “September 3 marks the 190th anniversary of the Hurricane of 1821, which saw flooding and destruction in the growing metropolis. In less than an hour a thirteen-foot storm surge deluged the city”

    ….see previous post for links

  44. philjourdan says:
    April 23, 2014 at 9:49 .
    Seems they are not sure if the elevator is going up, or the shaft is going down.
    Thanks for the laugh, just wondering who is getting the shaft?

    @ bernie 1815 I read the same thing . They were going to built a line of new dunes just inside the 12 mile limit, backfill the diked in land farm it and develop it and move the 12 mile limit out again , as a Dutchman, sounds like a plan to me wow in a few decades we can bike across to England!!!

    The article was in one of the A’dam’s news papers, I think it was dated early April!

  45. kenw says:

    April 23, 2014 at 1:59 pm

    “Those of us with a bit more experience in these matters know the value of marshes, wetlands, tide pools and other such features that have surely been eliminated over time in NYC.

    Houston remembers Ike.”
    =========================
    Got anything more than platitudes ?
    Please expand upon your “bit more experience”, and enlighten us.
    Memories might be short.
    Surely.

  46. My $0.02 worth:

    One of my nerdier hobbies is to check out old photographs, drawing and maps of where I live (opposite side of the Hudson river).

    On the NJ side, A good portion of the southern part of Jersey City (from Paulus Hood on down) was salt marsh. Hoboken used to be just an island surrounded by salt marsh. A lot of the land on the Jersey side didn’t exist back in the 1820’s. It came about later and land was extended out into the Hudson to accommodate the building of railroads, ports, housing, and factories,. Not enough land? Just make more!
    Same thing happened on the New York side. Battery Park area didn’t really exist before all the fill was dumped (from excavating the first WTC) there. A number of islands are also man made (most of Governor’s Island for example).

    Could the storm surges have gotten worse because there is a lot less marsh other other areas o take up the surge?

  47. I should have stopped reading after “assistant professor of civil and environmental engineering at Portland State University in Portland, Ore”

  48. “Sea level in the New York City metropolitan area has been rising between 2.2 and 3.8 cm (0.86-1.5 in) per decade for over a hundred years, as recorded on tide gauges. This includes a contribution of 0.86-1.1 cm (0.34-0.43 in) per decade from regional subsidence, predominantly due to glacial isostatic effects.” http://seaandskyny.com/2011/05/26/rising-waters-and-coastal-floods-living-with-sea-level-rise-in-nyc-part-22/

    Sea level at the New York tide gauge (The Battery) has risen 426mm in 157 years, a rate of 271mm/century (11″). Of that, 100mm/century (4″) is due to subsidence from glacial isostatic effects, so measured sea level rise (11″) minus subsidence (4″) leaves 7″/century, not much following the drop in sea level during the Little Ice Age. The New York tide gauge record begins in 1856, just at the end of the Little Ice Age (1450-1850AD).

    “(New York) is no stranger to tropical cyclones, in spite of its northerly location. A hurricane struck the city in 1821, producing a surge of 13 feet in 1 hour that flooded lower Manhattan as far north as Canal Street. In 1893, another hurricane submerged southern Brooklyn and Queens, erasing a small barrier island off the Rockaways. During the 20th century, the “Long Island Express” (1938), hurricane Donna (1960), and the weaker hurricane Gloria (1985) created extensive damage on nearby Long Island and in New Jersey. Even extra-tropical winter storms, such as the nor’easter of December, 1992, can result in widespread flooding of low-elevation neighborhoods and seriously disrupt ground and air transportation.”

    New York sea level fell 4mm from 1996 (7130mm) to 2013 (7124mm). In contrast, the New York City Panel on Climate Change experts using 7 Global Circulation Models (GCMs) and 3 IPCC emissions scenarios estimated that during the period 1996-2013, sea level would have risen 20mm (0.8″). The expert projection was for New York sea level increase of over one meter (39’4″) by 2100. The experts must be expecting a big speeding up very soon, because so far they have wasted 14 years with nothing happening that would suggest their 2100 estimate is correct.

    Besides isostatic effects, subsidence in highly developed urban coastal areas is also influenced by pumping of groundwater, blocking of siltation and increasing river flow rates by building levees and compaction of previously deposited silt, and erosion from the resulting loss of barrier islands, and organic decomposition resulting from changed surface land use.

    The Global Climate Models former Mayor Bloomberg’s experts used didn’t include subsistence factors, and only looked at sea level rise based on estimates of thermal ocean expansion and projected ice-melt. Since other recent studies have shown no increase in ocean temperature (a study of my own of six West Coast cities [San Diego, Los Angeles, San Francisco, Seattle, Victoria, and Vancouver] shows an average sea level decrease of 3″ since 1983), and a study of almost 500 glaciers showed that their rate of retreat 1850-1950 was higher than after 1950.

    I’m sure all of this would be good news to panicked New Yorkers, but all they will get is a steady diet of panic from the media. The simple truths of science will be cherry picked to paint a picture of a climate-doomed future.

  49. and adjusted the data where points were erroneous or missing, including using newspaper accounts of big storms to fill in some of the holes.

    But I can also think of other reasons why. Mainly urbanization. Areas that used to be meadow or marsh would absorb a lot of the rise and now it is all walled in and the water can’t spread out. It gets channeled into the harbor and up the rivers now with concrete “banks” in many areas.

  50. It’s well mapped how Manhattan has expanded into the sea. Here’s a pearler if anyone would like to see :) (H/T to this wonderful site)

    And at an apparent 2.77mm/yr sea level rise. OMFG. They’re all about to drown!

  51. Plenty of photos of the construction of the Brooklyn Bridge towers in the 1870s. Water levels are very little changed today compared to those photos. Note that the local tidal ranges for New York harbor are around 5 feet, but up to 7 feet depending on the time of the photo.
    Another water level reference is Bedlows Island, now called Liberty Island. Plenty of photos of construction of the Statue showing a pre-existing sea wall. The same sea wall exists today, but no obvious increase in sea level. The same caveat regarding daily tide changes here.
    Also, Sandy was not a hurricane, as has been covered many times.

  52. I’ve long been curious about the Battery Park real estate formed by dumping rubble from the WTC. From the bush in Oz it’s hard to find out the details. My understanding is that the mouth of the Hudson was narrowed by up to 700 feet. True? Or true only in part? False?

    I can tell you this: Sydney, unlike NY, is not a low-lying metropolis in a hurricane belt. But if anybody in the last fifty years had suggested infilling even a tiny fraction of our massive harbour the whole population would have screamed.

    My questions about Battery Park (provided what I have heard is true): Were the responsible parties ever prosecuted? Weren’t there state, federal or maritime authorities with a say? Are there any individuals now prominent in NY government and/or business who favoured or profited from the development? Are any of these people the same ones who are now keen to attribute the flooding to AGW?

    I understand that there has been bad luck and bad bungling in the past. Nobody is perfect. But to deliberately narrow a river mouth to make more low lying real estate in a notorious hurricane belt? It’s enough to make you doubt the sophistication of New Yorkers, and I know what a shocking statement that is for some. They had the experience of 1935…and still dumped rubble in the mouth of the Hudson? Whew!

    I am one very curious outsider.

  53. I just believe that Global warming is being used as an excuse to do nothing and just blame emissions for doing nothing. There is historical evidence on NYC flooding due to rare events in the past and yet we see nothing being done to stop flooding from occurring again. If the are worried then they should be building a levee system to stop the water from flooding the city, but nothing like that looks to be even being proposed.

  54. Since the Hudson River feeds into NY Harbour has anyone bothered to note the status of said River at the time? Abnormal or High Rainfall perhaps upstream?

  55. I see 1821 in the above post. What happened in 1821?

    1821 HURRICANE
    Reaching the City on September 3, 1821, the storm was one of the only hurricanes believed to have passed directly over parts of modern New York City. The tide rose 13 feet in one hour and inundated wharves, causing the East River to converge into the Hudson River across lower Manhattan as far north as Canal Street. However, few deaths were attributed to the storm because flooding was concentrated in neighborhoods with far fewer homes than exist today.

    http://www.nyc.gov/html/oem/html/hazards/storms_hurricanehistory.shtml

    http://stevengoddard.wordpress.com/2012/05/05/sea-level-isnt-rising-manhattan-is-sinking/

  56. This is a most curious paper. They make an odd claim. They say that the storm surge in NYC has gone up by 2.5 feet since the mid 1800s.

    However, we have actual tidal data for the period. Since the mid-1800s, the RELATIVE sea level at the Battery in NYC has gone up by only one and a half feet.

    Now, it’s possible that the storm surges have increased. If so, it’s likely from siltation, because the V-shaped nature of the New York harbor area means the resulting surge is dependent on the bottom geometry. But I’d need a lot more data before I bought into the story …

    Next, despite the 2.5 foot rise claimed in the lede, further on it says:

    Specifically, Talke explained, there’s a 10 percent chance today that, in any given year, a storm tide in New York harbor will reach a maximum height of nearly two meters (about six and a half feet), the so-called “10-year storm.” In the mid-19th century, however, that maximum height was about 1.7 meters (about 5.6 feet), or nearly a foot lower than it is today, according to tide gauge data going back to 1844, he noted.

    “What we are finding is that the 10-year storm tide of your great-, great-grandparents is not the same as the 10-year storm tide of today,” Talke said.

    So in that quote, despite the 1.5 foot rise in sea level, he’s saying the storm tide has only increased by one foot, which is LESS than the relative sea level rise … what happened to the 2.5 foot increase trumpeted in the lede?

    w.

    PS—The best claim was this one, saying that they had:

    … adjusted the data where points were … missing, including using newspaper accounts of big storms to fill in some of the holes.

    I love it. Making up missing data data out of the whole cloth, or guessing at missing data from newspaper reports, is now officially called “adjusting” your data. If I could only “adjust” my bank account in the same manner …

  57. [The preliminary abstract of the paper is below]

    Abstract
    Increasing Storm Tides in New York Harbor, 1844-2013†
    S.A. Talke1,*, P. Orton2 andD.A. Jay1
    Three of the nine highest recorded water levels in the New York Harbor (NYH) region have occurred since 2010 (Mar. 2010, Aug. 2011, and Oct. 2012), and eight of the largest twenty have occurred since 1990. To investigate whether this cluster of high waters is a random occurrence or indicative of intensified storm tides, we recover archival tide gauge data back to 1844 and evaluate the trajectory of the annual maximum storm tide (AMST). Approximately half of long-term variance is anti-correlated with decadal-scale variations in the North Atlantic Oscillation (NAO), while long-term trends explain the remainder. The 10-year storm-tide has increased by 0.28 m. Combined with a 0.44 m increase in local sea-level since 1856, the 10-year flood-level has increased by approximately 0.72 ± 0.25 m, and magnified the annual probability of overtopping the typical Manhattan seawall from less than 1% to about 20-25%.

    http://onlinelibrary.wiley.com/doi/10.1002/2014GL059574/abstract

  58. An important factor in these situations is the physical shape of the shoreline (which can be modified by human or natural action), submarine topography (likewise) and the configuration of the continental shelf break (submarine landslides can alter this). These changes will affect the locations of convergences and divergences of incoming water masses. Changes in sea level will also affect the significance of topography on the magnitude of these flows, and not always in the corresponding direction.

  59. u.k.(us) says:
    April 23, 2014 at 3:07 pm
    Got anything more than platitudes ?
    Please expand upon your “bit more experience”, and enlighten us.
    Memories might be short.
    Surely.

    surely, indeed.

    google Hurricane Ike. or any other large gulf hurricane where storm surge was a factor. Even try the Galveston Hurricane of 1900 (no name). We (USA Gulf coast residents) are awash in data for such. I’ll allow you the priviledge of learning about it on your own. Follow that seach with ones for not buildiing on barrier islands, filling in marshes, tide lands, etc. These actions increase storm surge penetration by removing natural dissipation. The tides aren’t getting all that higher, but they are penetratiing farther inland as the natural features disappear thru poor land use.

  60. In the last fifty years, the apparent sea level has risen 6 inches at The Battery in New York, according to the New York State Sea Level Rise Task Force Report to the Legislature dated Dec 31, 2010. NOAA’s NGS finds that 4.3 inches of that six inches consisted of the Battery sinking towards the center of the Earth due to AIG Subsidence. This is just the last 50 years. If we extrapolate that over the last 170 years: AIG would account for approximately 14.6 inches (Battery sinking) — accounting for the majority of the “sea-level rise, which is occurring globally, has raised water levels along New York harbor by nearly a foot and a half since the mid-19th century”. Please see my essay at http://wattsupwiththat.com/2014/01/27/what-to-do-about-the-flood-next-time/.

    The most probable explanations for “Maximum water levels in New York harbor during major storms have risen by nearly two and a half feet since the mid-1800s, making the chances of water overtopping the Manhattan seawall now at least 20 times greater than they were 170 years ago, according to a new study” (in addition to the 14 inches of land subsidence) are 1) restricted access to flood plains for the rising storm surge waters to flow onto due to development — either outright denied access or restricted channel flow (anyone growing up in or around the New Jersey Meadowlands will understand this) and 2) silting and narrowing of the actual river basins and bays themselves, so that they hold less volume of water in their “normal” states.

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