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Far out in North Carolina

Filed under: — stefan @ 24 June 2012

The extensive salt marshes on the Outer Banks of Carolina offer ideal conditions for unravelling the mysteries of sea level change during past centuries. Here is a short report from our field work there – plus some comments on strange North Carolina politics as well as two related new papers published today in Nature Climate Change.


The Outer Banks of Carolina are particularly vulnerable to coastal erosion and sea-level rise, partly because the land is subsiding and the banks are naturally moving landward. On the ocean front, land is continually being lost.

At 11.20 AM we get a walky-talky call from the research vessel Stanley Riggs which anchors a bit offshore from us: a few meters behind us is a shark in the water they say. They’ve been observing it through their binoculars. We haven’t noticed a thing and turn around, but only the student Ray catches a glimpse of the fin before it disappears. We’re standing on a bit of peat surrounded on three sides by water, drilling a core. Sharks don’t bother us – but the people on the ship are worried about our divers who plan to go in the water shortly. We don’t see the shark again – only little snakes elegantly gliding past through the water, heads above the surface, and some crabs, a popular local delicacy.


R/V Stanley Riggs lands our team at Sand Point.

To us as onshore crew, alligators would be far more interesting than sharks. Last week, not far from one of the study sites a man was injured by an alligator. My colleagues reassure me: alligators are nothing to worry about, as long as you can run faster than the slowest person in the group. But everything looks as peaceful as it can be now. The sun glitters on the lagoon, every now and then a group of pelicans patrols over our heads and convective clouds are billowing near the horizon. Sometimes we hear thunder rolling in the distance, but it stays dry all day. What a contrast to the previous day! A cold wind and constant rain bothered us and a series of technical failures meant that we did not even bring a useable core home. A dozen people worked a whole day in vain. (No hint that day of the fact that this May was the warmest on record in the Northern Hemisphere!)

The day I arrived on the Outer Banks I’d been greeted with news of a 50:50 chance of a tropical storm developing offshore. The same evening the first tropical storm of the season was called by the National Hurricane Center: Alberto. In mid-May – the hurricane season officially only starts in June (it turned out to be only the third May on record with two tropical storms in the Atlantic). The Outer Banks are very exposed. Several times in the last decades a hurricane caused a break in the barrier island and washed away the only road connection to the mainland. Luckily, Alberto turned offshore and passed far out at sea without bothering us.


Andy Kemp (on right) with students Ray and Hanna.

We’re here because of the several metres thick peat layer which has accumulated during the past millennia behind the Outer Banks. The land here is still sinking since the end of the last Ice Age, because it is located on the glacial forebulge: a zone around the edges of the glacial ice sheets that was pushed up when the ice load was pushing down adjacent lands. So instead of getting post-glacial uplift it suffers from post-glacial subsidence. The subsidence has led to a continuous sea-level rise relative to the land of around one millimetre per year. The salt marsh is able to keep up with this rise by accumulating sediments and building up peat, about a metre per millennium. This provides a unique opportunity to reconstruct the speed of relative sea-level rise – and by subtracting out the land subsidence, also the absolute sea-level changes.

I’ve already reported here on the previous results of our collaboration with the team around Ben Horton of the University of Pennsilvania: it was possible to reconstruct sea level for the past 2,000 years and to link the variations of the last 1,000 years to the global temperature evolution (see graph in that earlier post). Now we’re here to look for even older, thicker peat. Some of the oldest peat may well have been flooded in the meantime and be sitting at the bottom of the lagoon, hence we’re also coring from aboard the research vessel run by East Carolina University. After more than a week of coring, the peat is looking promising – but only months-long efforts in the lab will show whether the new cores are suitable for reconstructing sea level.

North Carolina politics

On the last day we hold a stakeholder workshop in Nag’s Head. NOAA, the funding agency, requires this type of direct discussion of the project scientists with potential users of the results, e.g. from local planning authorities. Sea-level rise is right now a hot topic in North Carolina: an interest group called NC20 has proposed a rather bizarre piece of state legislation that would ban the use in planning of scenarios of accelerated future sea-level rise (as recommended e.g. by the guidance document of the US Army Corps of Engineers, who assume a “high” scenario of 1.5 metres – about five foot – sea-level rise by the year 2100). And yes – NC20 was represented at our stakeholder workshop. Here is a leaflet that they distribute. The group tries to discredit the credibility of science by propagating the myth that climate science predicted global cooling in the 1970s. In truth this cooling idea was never main-stream but a small minority view also in the 1970s. CO2-induced global warming was in fact correctly predicted in classic papers e.g. in 1972 (Sawyer in Nature) and 1975 (Broecker in Science).


Dark clouds gather over the beach at Jennette’s Pier where we hold our stakeholder workshop. Not long after a thunderstorm strikes. The wide beach is artificial: result of a beach nourishment project for $ 36 million in the previous year. Environmentalists are critical of the beach nourishment. [All photos (c) S.R.]

Of course, global sea-level rise has already accelerated in the course of global warming (as many scientific papers have demonstrated – including the data from the peat cores in North Carolina), and will almost certainly accelerate further as the planet warms. After all, ice melts faster the warmer it gets, and the oceans also heat up faster. In other words, this law would have banned taking reality into account in planning. It was passed recently by the Senate of North Carolina, albeit with some rewording that softens up the central clause, but looks unlikely to become law this year. The Colbert Report has a rather funny comedy piece on the sea level law. This story was topped by a Senator from northern neighbour Virginia, who apparently said that “sea-level rise is a left-wing term”.

Two new papers

Nature Climate Change publishes two new sea-level papers today. One, by Sallenger et al., is an analysis of US tide gauge data. The main finding is that there is a “hotspot” of acceleration in sea level rise over the past sixty years on the US Atlantic coast, with the largest acceleration found between Cape Hatteras and Boston. The authors argue that this pattern is consistent with a weakening of the Atlantic overturning circulation (and hence their first reference is to our 2005 paper where we show this sea-level pattern in our model). In my opinion an intriguing possibility that warrants further investigation. There could be other causes, like interdecadal changes in the wind field.

The other paper, by Schaeffer et al. (disclosure: I am a co-author on this) estimates global sea-level rise up to the year 2300 using a semi-empirical approach. The paper exploits the observed relationship between global temperature and the rate of global sea-level rise and was calibrated using the sea-level proxy data from North Carolina for the past millennium. For the main results, see the graph below, which also includes the proxy data (click to enlarge). Ironically, it is thus the historic data from North Carolina that lead us to rather grim expectations of future sea-level rise.

Links

More photos: see my US Atlantic Coast set on Flickr.

Press release for the Schaeffer et al. paper
Realclimate: 2000 years of sea level
Realclimate: Is sea-level rise accelerating?
Sea-level pages of the Potsdam Institute

Update: a few links to media articles about this topic

The Guardian: Scientists warn US east coast over accelerated sea level rise
New Scientist: Sea-level rise accelerates faster on US east coast
The Wall Street Journal: Sea rise faster on East Coast than rest of globe
Nature: US northeast coast is hotspot for rising sea levels
Le Monde (in French, quotes this Realclimate article)
Sea-level panel’s mainstream report – article by Rob Young, a member of the NC sea-level panel.


139 Responses to “Far out in North Carolina”

  1. 51
    Lennart van der Linde says:

    @42 Martin Vermeer: The 6,5 meters SLR in 2300 in the CPH reference scenario I extrapolated from this table in your paper:
    http://www.nature.com/nclimate/journal/vaop/ncurrent/fig_tab/nclimate1584_T1.html

    My reasoning was: max 139 cm of SLR in 2100 + max rate of SLR of 26 mm/yr in 2100 ‘could’ mean about 6,5 meters by 2300, if that rate of SLR would continue for two centuries.

    I admit that the table does not give all the information needed to make this extrapolation, and for lower scenarios the rate of SLR declines significantly after 2100, so that’s why I asked if I understood correctly. So the question is if and how fast the rate of SLR declines after 2100 in the CPH reference scenario. Do your modelling results give an answer to that question? And did you also model even higher scenarios than CPH reference? If so, what were the results for those?

  2. 52
    T. Marvell says:

    I live hear the Virginia and North Carolina shores; public concern about sea level rise is small compared to concerns about hurricanes. Their impact is much more immediate. It is harder to tie hurricanes to global warming then SLR, even though hurricane damage is affected by sea level and ocean temperature. Still, the way to affect public policy is through scares of hurricanes, rather then SLR directly.

    Most hurricane damage along the shore is by water, as opposed to wind. Private insurance companies insure against wind damage only, and insurance rates have increased about 300% in the past decade along the shore. Flood insurance, granted by the Federal Government, has not increased nearly as much.

    For almost 50 years Federal flood insurance has been attacked as one of the stupidest Federal handouts, since it encouranges building in flood prone areas. Without it, public conern about global warming would probably be greater.

    Right-wingers who contest the idea of SLR are typically opposed to federal programs. As far as I know they have not attacked Federal flood insurance. This inconsistency could be used to question their credibility.

  3. 53
    dbostrom says:

    T. Marvell: I live hear the Virginia and North Carolina shores; public concern about sea level rise is small compared to concerns about hurricanes.

    Yeah, and that’s odd because with hurricane behavior held at a constant sea level rise is going to guarantee that the impact of each storm making landfall will be worse.

    Not to bang on about it but the Climate Central interactive sea level map illustrates this nicely. It’s about changing probabilities; a neighborhood need not be permanently underwater before it’s effectively useless.

  4. 54
    Tokodave says:

    And another note…a storm doesn’t have to be a hurricane to have major impacts…see Florida today. Extreme weather events do not have to rise to the various naming thresholds to cause major impacts.

  5. 55
    dbostrom says:

    Here’s another weird outcome of living in a pretend world.

    Fifty years from now people who insist that sea level behavior has not varied from bygone times will have to explain more frequent and severe coastal flooding by some other means; it’ll be necessary to invent an alternative explanation for observations. Thus something else will have to be exaggerated, perhaps hurricanes. Supposing that hurricanes behave no differently, some folks nonetheless will need to insist that hurricanes are worse.

    That is, presuming human nature still precludes “oops, I’m wrong.”

    I’m sure some philosopher somewhere has explored the notion that facts are conservative, that it’s not possible to vanish the real.

  6. 56
    John E. Pearson says:

    The article said: “The group tries to discredit the credibility of science by propagating the myth that climate science predicted global cooling in the 1970s. In truth this cooling idea was never main-stream but a small minority view also in the 1970s.”

    Here’s Mr. George Will just flat out lying in a 2006 opinion piece published in what was at one time a decent paper: (http://www.washingtonpost.com/wp-dyn/content/article/2006/03/31/AR2006033101707.html)

    “when he was 20 he was told to be worried, very worried, about global cooling. Science magazine (Dec. 10, 1976) warned of “extensive Northern Hemisphere glaciation.” ”

    Now Mister Will didn’t expect anyone would actually go and look at the actual papers he was misrepresenting. Here’s the one mentioned above: Variations in the Earth’s Orbit: Pacemaker of the Ice Ages J. D. Hays, John Imbrie, N. J. Shackleton
    http://www.sciencemag.org/content/194/4270/1121.abstract

    Here’s the relevant cut and paste quote from the Hays et al article:
    ——————-snip———————————
    A model of future climate based on the observed orbital-climate relationships, but ignoring anthropogenic effects, predicts that the long-term trend over the next sevem thousand years is toward extensive Northern Hemisphere glaciation.
    ——————-snip——————————————–

    As you can see there is nothing in the actual text that suggests we ought to be “worried, very worried” (as Mr Will prevaricated), or even mildly alarmed, about the extensive Northern Hemisphere glaciation that were predicted would occur on a 7,000 year time scale by a single climate model in the absence of anthropogenic effects.

    I provided a similar illumination of Mr Will’s mendacity in a comment on the column at the time they published it and which stayed there for some time but as far as I can it has now been removed. From time to time it seems worth bringing up. At the time I was surprised that George Will didn’t know how easy it was to debunk his lies but in retrospect I’m thinking that maybe he didn’t care, knowing that they’d be repeated 1,000s of times anyway.

  7. 57
    SecularAnimist says:

    John E. Person wrote: “At the time I was surprised that George Will didn’t know how easy it was to debunk his lies but in retrospect I’m thinking that maybe he didn’t care”

    Your retrospective thinking is correct. George Will didn’t care.

    The evidence that he didn’t care is that over the course of several Post columns about global warming, he repeated lies that had already been thoroughly debunked, not only by letters to the editor from scientific organizations, but by the Post’s own reporters.

    And the Post’s editorial page editor, Fred Hiatt, didn’t care either. His response to the debunking of Will’s lies was to assert that Will’s columns were “an important contribution to the debate” and to continue publishing them, even though they contained the same lies that had already been debunked.

  8. 58
    Martin Vermeer says:

    Lennart van der Linde #51:

    My reasoning was: max 139 cm of SLR in 2100 + max rate of SLR of 26 mm/yr in 2100 ‘could’ mean about 6,5 meters by 2300, if that rate of SLR would continue for two centuries.

    OK, I see. Ball-park reasonable, but that ‘if’ is a big one. Yes, the other scenarios see the rate of sea-level rise go down after 2100, and it’s a reasonable question whether this also applies to CPH reference and CPH policy.

    Looking at Figure 2 we see that, up to 2100, the increase in rate indeed goes down. Whether the rate itself does at any point? To know that, we would need to have these curves (and uncertainty bands) extended by two more centuries. Extending the underlying temperature curves amounts to making assumptions on human behaviour (by 2100 we are already looking at 3 degrees plus. How dumb can we get? Don’t answer that), available fossil-fuel stocks, and technologies. We didn’t want to go there.

    Note that the “point” of our paper is not so much showing how bad it can get; rather, to provide actionable information on the effect of various mitigation approaches, and levels of aggressiveness in mitigation, that have been floated or pre-exist in the literature.

  9. 59
    dbostrom says:

    Some fun remedial (for me) reading on the topic of sea level. The gravitational part is especially amazing. Buy waterfront property in Iceland, watch it grow…

    These polar ice caps are Stouffer’s gorillas. They keep sea level higher than it would otherwise be for thousands of kilometers around both land masses, and correspondingly lower elsewhere.

    If the polar ice sheets shrink, though — as they’re currently doing, especially in Greenland and West Antarctica — their gravitational pull weakens and so does their hold on the surrounding water. About a year ago, Jerry Mitrovica, a geophysicist who teaches an entire course on sea level at Harvard, co-authored a paper in Science that laid out what would likely happen if the West Antarctic ice sheet, the smaller of the two sheets that cover the Antarctic continent, were to melt. (Like a complete shutdown of the Gulf Stream, this is not considered likely anytime soon. But recent satellite measurements have shown that glaciers that drain the ice sheet have begun moving faster toward the sea).

    If you simply spread the resulting increase in sea level evenly around the world, it would amount to about 5 meters’ worth. But the ice sheet’s gravity is currently keeping sea level artificially low in the Northern Hemisphere, so if it disappeared, the actual increase along the U.S. mid-Atlantic coast would be more like 6.3 meters. In other words, as the West Antarctic Ice Sheet melts and loses mass, its pull on the surrounding ocean will lessen. Seas will drop around Antarctica and parts of the Southern Hemisphere, and that water will be displaced to more northerly areas, such as the east coast of the U.S.

    Now that the gorilla has made its presence known, Stouffer is working with Mitrovica to understand its effects in greater detail. A joint paper, due out in a few months, will look into the gravitationally driven sea-level changes a melting Greenland could trigger. “The signal is so large,” says Stouffer, “that if you own beachfront property in Iceland, and all of the ice on Greenland melts and adds seven meters to average sea level, you end up with more beach. But in Hawaii, you get your seven meters of sea-level rise plus an extra two or three on top of that. It’s phenomenal to me that it matters that much.”

    The Secret of Sea Level Rise: It Will Vary Greatly by Region

  10. 60
    Martin Vermeer says:

    …and another reason why we didn’t want to go there is that our semi-empirical model is calibrated only over a period where there were temperature variations of up to 1 degree C. While it seems reasonable to extrapolate out to 1.5 – 2 degrees of warming, extrapolation of such a simple linear model to three degrees plus, sustained over many years, would become questionable.

  11. 61
    prianikoff says:

    re.45,47

    I meter/year is the average rate of coastal erosion for that section of the East Anglian coast. This is based on historical and archaeological evidence dating back to Roman times.
    The geological evidence indicates that it’s been similar for more like 5,000 years.

    The Eustatic Sea level rise affects the rate, but is not the only factor. As on the East Coast of the USA, this is a coast near a former Glacial margin, so it’s tending to sink.

  12. 62
    Lennart van der Linde says:

    @Martin Vermeer 58: I hope the point of your paper will be well taken. This information seems very important to me. Nevertheless, the additional point I’m taking from your paper seems equally important: if we don’t mitigate agressively enough we take a significant risk of levels and rates of SLR that will be very hard or impossible to adapt to, even for a rich country like The Netherlands.

    If I read your paper correctly than your conclusions go further than those of the Dutch Delta Committee:
    http://www.deltacommissie.com/doc/deltareport_full.pdf

    They thought 3,5 to 4 meters SLR by 2200 the worst case scenario. It seems their highest warming scenario by 2100 was somewhat higher still than your CPH reference scenario. If not, let us know.

    Your CPH reference could lead to max 4 meters SLR by 2200, by the same ball-park approach as above. So an even warmer scenario, like the Delta Committee could presumably lead to even some more SLR by 2200.

    I hope we will be wiser than to let it come that far, but so far we can’t be sure of that. Information like this may help us become wiser sooner.

  13. 63
    BillS says:

    Re #1 & #4 and Insurance

    In my part of the country (Maine) insurance companies and lawyers got interested in the prospects of sea level rise with a changing climate at least 5 years ago. While outside of my area, I believe both groups continue to solicit information from the science community. What they do with this information is, of course, another matter. The state’s coastal communities are likewise taking sea level rise seriously because coastal erosion is already a problem in some areas.

  14. 64
    JCH says:

    Steve Easterbrook – outside of the lighthouses and beaches and dunes, there isn’t really a lot to see on the outer banks, but when I lived there one of my favorite places was Ft. Macon (captured during the Civil War and well preserved.) There was a live oak forest just outside of Emerald Isle. I could always find a rattlesnake in there somewhere. I fear the forest is probably gone now. I was lucky to be there before the big development took place.

  15. 65
    BillS says:

    Steve Easterbrook & JCH….

    The importance of barrier islands is not what you can see but what you don’t. The dune structure of the islands themselves is interesting and within each subsection are ecologies that often exist no where else. Behind the islands into the protected bays and sounds are the nurseries for a vast web of marine and terrestrial creatures. From the backside of barrier islands, across the bays to the tidal salt marshes of the continental shore are the spawning grounds, the breeding grounds for thousands of species that do not exist in any other environment. Yet, this is a naturally dynamic environment and the creatures therein have adapted and, as with all such places, the mix changes as the environment changes.

    Want to know what barriers islands are really about? Find an old bay-man and ask him to show you about.

  16. 66
    Chris Dudley says:

    Is similar work being done along Assateague Island or further down along the Delmarva Peninsula? Subsidence from an ancient bolide impact may provide a useful range of background rates there.

  17. 67
    Gilles says:

    A question : when do you expect the acceleration to be statistically significant enough to be detectable, reaching say a 5 mm or 0.2 inches/yr ? It may be reasonable to wait a little bit to be sure your semi-empirical model is really confirmed by observations before “planning” anything for the next 100 years, to say nothing of 300 years ..

    [Response: Your point is about model validation, and there are two possibilities. Either you wait some decades to see whether the projections come true. Or you validate with hindcasts. For example, in this paper I have shown that when you calibrate the model only with the first half of the data (i.e. the period 1880 to 1940), you can quite nicely predict the sea level rise since 1940 with it. -Stefan]

  18. 68
    Dan H. says:

    Gilles and Stefan,
    The Rahmstorf paper does show a reasonable correlation between 1880 and 2000. However, the paper forecast that SLR should have reached the 5mm/yr rate by now, with error bars from ~3.75 – 6.25 mm/yr (extrapolating fig. 1 out to 2010). The most recent SLR lies clearly outside this range. If an acceleration in SLR is to occur, it should be readily evident in the very near term, in order to reach some of the higher predictions.

  19. 69
    Hank Roberts says:

    > Either you wait some decades to see whether the
    > projections come true. Or you validate with hindcasts.

    Very helpful to see this implication spelled out clearly, Stefan — you wouldn’t write that in the published paper, written for people who understand statistics.

    For the rest of us :-) it helps to be here working out clearly the very basic information about how you can get information by looking at this particular data set, which has this amount of internal noise/variability during this particular time span.

    Am I right that each high tide (one per 24 hours, in North Carolina, compared to two in 24 hours in California) can be a data point?

    I understand, I think, that to do a significance calculation on noisy data takes a certain number of data points or observations — for “annual” data you have to wait years; but for tides?

    (I’m trying always to remember my fellow citizens’ average reading comprehension for _non_scientific material is somewhere around 7th or 8th grade; so I’m trying to ask this stuff as simply as possible.)

  20. 70
    Unsettled Scientist says:

    Dan H. does bad science (or just likes to smear confusion around).

    >(extrapolating fig. 1 out to 2010)

    Figure 1 is a graph projecting the second half the 1900s using data that stopped at 1940. The entire point is to show that the model’s forecast fits the already measured data when you only use the first half of the set. Its purpose is not to project in the future. The paper did not forecast anything about what is happening now with Figure 1. Surely you wouldn’t take a model and run it on data from 1880-1940 to forecast into the future, you’d include the entire data set.

    BTW, that’s also not the paper, it’s the response to comments. I assume you cannot be talking about the actual paper because Figure 1 in the paper is not a forecast.

    Lay readers – yet another example of Dan H. not understanding the source material.

  21. 71
    Susan Anderson says:

    I don’t think the Norfolk coast of England is a good example – as noted, it has degraded continuously for quite a long time. There are places that grow and places that diminish, and the geography of that area makes it one of the diminishing ones. We visited it in the early 60s and there were crumbling houses then. Of course, this will increase, but it makes it a bad example.

    Gilles likes to throw dust in the eyes but waiting on events seems particularly foolish in the light of the increase in newsworthy disasters lately. It seems pretty clear that a complex of interrelated phenomena are making flooding and droughts worse, as predicted, increasing the seasons for destructive insects, and other large and small changes over time. It would be nice if people were a bit more interested in things that happen beyond their own horizons (world rather than local weather news, for example, over time) and more observant. The increase in personal portable media allows people to seek virtual rather than real entertainment.

  22. 72
    Susan Anderson says:

    Norfolk Coast near East Anglian Coast. I think the meter per year loss was meant to be horizontal rather than vertical and matches our observation; also agree it’s a bad argument.

    The Delmarva/Chesapeake area is likely in real trouble, between toxifying shallow water and a lot of low ground.

  23. 73
    Hank Roberts says:

    Dan H. lectures Gilles and Stefan on Dan’s misinterpretation of the meaning of the Rahmstorf paper. It would appear Dan H. doesn’t know Stefan’s last name. Or

    …. dagnabbit, hooked again.

  24. 74
  25. 75
    Observer says:

    At 52, the write stated
    Right-wingers who contest the idea of SLR are typically opposed to federal programs. As far as I know they have not attacked Federal flood insurance. This inconsistency could be used to question their credibility.
    =======================

    Well, a little research might be useful before making such an argument—arguments that are easily refuted can damage the credibility of those who put them forward and tarnish other arguments that they are associated with.

    I believe that the bulk of the criticism of subsidized flood insurance comes from the right.

    See, for example, http://www.cato.org/pubs/regulation/regv16n3/v16n3-2.pdf at page 15.

    I did a search on the cato website and got a number of hits.A quick scan of these hits did not reveal any that were positive.

    Given that federally-subsidized flood insurance is (a) an unnecessary and inefficient intervention in a part of the economy in which the market could work, and (b) flood insurance nets out as a transfer from taxpayers to a selected class, one would expect that the right would oppose it. One would hope the left would oppose it also and that support would be restricted to those who own property in flood plains. Maybe it more or less is; if, perhaps they care more and lobby harder than the rest of us.

    Observer

  26. 76
    John E. Pearson says:

    75: Observer. All God’s dangers ain’t a Cato institute. As the late Tip O’Neil said, “All politics is local.” http://www.govtrack.us/congress/bills/112/s3051

  27. 77
    flxible says:

    … support would be restricted to those who own property in flood plains. Maybe it more or less is; if, perhaps they care more and lobby harder than the rest of us.
    successfully lobbied 94% of the House??

  28. 78
    dhogaza says:

    I believe that the bulk of the criticism of subsidized flood insurance comes from the right.

    Cato is not “the right”. Nor the “bulk of the right”. Do your homework.

  29. 79
    OldNavy says:

    I have lived in NC for 20 years. There are few coastlines as volatile as the barrier islands of NC (especially the Outer Banks). The coastline is in constant flux due to the Gulf Stream and periodic hammering by hurricanes. Forget about decadal changes, I have seen enormous changes from week to week.

    I cannot think of worse place to conduct a study of sea level rise due to the tremendous natural variability. Why not conduct a sea level rise study of the Rock of Gibraltar and other relatively fixed shorelines? Places where the volatility is low.

    [edit - uncalled for]

    [Response: You need to read the previous post on why people are looking in NC - it has nothing to do with the shifting coastlines, but rather that the salt marshes are affected by post-glacial sinking which meants that accumulating sediment is accessible and can be examined to see periods of relative accelaration and decellaration. - gavin]

  30. 80
    prianikoff says:

    re.71

    The coastline in Norfolk and Suffolk isn’t uniformly in retreat.
    Eroded sand is often deposited further along the coast, causing sandspits and beaches to grow at certain locations.
    Coastal defence works can mitigate the rate of retreat, while dredging the offshore sandbanks can increase it.

    For instance, in the centre of Southwold, money has been spent on beach nourishment and maintaining the sea defences.
    Whereas, north of the town, where there are fewer homes and no tourist facilities, spending has been cut.
    It’s in the latter areas that coastal erosion is occuring most rapidly.

    However last summer, I noticed that a section of footpath near the town centre beach was closed due to subsidence.
    Officially this was put down to “rabbit activity”.
    As Sizewell Nuclear power station is only 10 miles south, I just hope the rabbits aren’t breeding faster due to global warming!
    Last March the Department for Environment conducted an unpublished analysis which said Sizewell is at at “high risk” of flooding and coastal erosion because of climate change
    (as are 12/19 other nuclear power stations in the UK).

    As part 1 of the video about Happisburgh shows, revetments which once slowed down erosion are falling into disrepair.
    see:-
    http://www.bbc.co.uk/learningzone/clips/living-with-coastal-erosion-in-happisburgh-east-anglia-pt-1-2/7361.html

    This is a deliberate policy, usually described as “Managed Retreat”.
    It entails allowing the coastal marshlands to expand and the sea to permeate reclaimed agricultural land.
    The theory being that this will become a buffer zone, preventing disastrous flooding in the future.
    The economic arguiment is that the cost of maintaining sea defences outweighs the value of the properties threatened.
    It’s also argued that building “hard” sea defences cause problems elsewhere along the coast.

    Some useful comparisons could be drawn with the Netherlands.
    East Anglia and the Fenland have close historical associations with Holland.
    In the 17th century, Dutch engineers helped drain the marshes and opened up the region for intensive farming.
    Even then, it was a very contentious issue, as much common land was enclosed in the process.
    As the land dried out, it fell below the level of the drainage ditches.
    Only the advent of steam pumps prevented the Fens being flooded again.

    The Dutch have a more agressive attitude towards their coastal defences.
    The West Frisian Islands are a chain of barrier islands, not unlike those on the US East coast.
    Periodically, they’re split apart by storm surges, disappear and re-grow.
    Attempts to fill in the channels seperating them from mainland have always failed.

    But the Dutch spend a lot more on coastal defence, because allowing their coast to be breached threatens the densley populated low-lying region inland.
    As their saying goes:-
    “Hier gaan over het tij, de wind, de maan en wij”
    Perhaps they need to work global warming into that (if they can get it rhyme).

  31. 81
    Ray Ladbury says:

    It would seem to me that it is pointless to argue whether support for subsidized flood insurance comes from the right or the left. It is either a good idea or it is not.

    NC-20′s silliness is manifest whether they come crying to the ebil gummint for insurance relief or not. That is just a measure of how sincere they are–and thier webpage makes a pretty good case that they are not already.

  32. 82
    dbostrom says:

    prianikof: I just hope the rabbits aren’t breeding faster due to global warming!

    Night of the Lepus:

    members of a small Arizona town…battle thousands of mutated, carnivorous killer rabbits.

  33. 83
    Observer says:

    Re: 78 and 81 above.

    78, well sure, Cato is not the bulk of the right.
    But, do a search on
    reason.com
    “A recent study by the National Wildlife Federation, a leading environmental group, documents the high tide of insanity that is the federal flood insurance program….”

    aei.org
    “This policy brief will survey how human nature, facilitated by well-intentioned but flawed government policy, leads more people and property into harm’s way, undermines insurance markets, and transfers the costs of flood risk to distant taxpayers.”

    Milton Friedman
    “Friedman corrected the questioner and noted that he did not come out against private aid for flood victims but instead was against the Federal Government providing discounted flood insurance in advance to home purchasers which motivated people to build houses in areas where they otherwise would not have been able to obtain insurance privately.”

    http://www.rightwingnews.com/column-2/out-of-order/

    “Perhaps hoping to undercut my credibility by eliciting my opposition to federally subsidized flood insurance (a program that he likely believes to be beyond controversy), I explained how those guarantees cost society money by eliminating barriers that would normally prevent people from living in potentially dangerous flood zones. The congressman gave no indication that he ever considered these arguments.”

    I could go on and on but why?

    Re, 81.
    In some absolute sense it is not important what the political views of those who support and oppose flood insurance are.

    But, if one wants to understand political disputes or influence the development of policy, it probably helps to understand the facts. If, as I think likely, support for flood insurance is stronger on the left than on the right, telling people that the right is the problem may make people think less of the right but it probably will not help in moving towards the adoption of more ecologically sound public policy.

    But, of course, as in many things, the best action depends on your goal. I don’t see how an undocumented assertion that the right supports flood insurance serves environmental policy goals.

  34. 84
    wili says:

    So how much exactly is the AMOC slowing? What are the causes? Is this related to the very cold, wet summer much of Europe seems to be having? Is it getting slower, and is that rate of slowing accelerating (if that makes sense)? Any possibility that it will stop altogether?

    On a different tack, do the above studies on global sea-level rise include results from this study showing that GIS is near a tipping point?

    http://thinkprogress.org/climate/2012/07/01/508782/greenland-ice-sheet-melt-nearing-critical-tipping-point/

    (Sorry for all the impertinent questions.)

  35. 85
    dhogaza says:

    Observer:

    “I could go on and on but why?”

    Good call, because it’s pointless. Because for every critic on the right I can find two on the left, if you insist on playing this pointless game.

    I’m with Ray:

    It would seem to me that it is pointless to argue whether support for subsidized flood insurance comes from the right or the left.

    It is also pointless to argue that the NC-20 group is unrepresentative of a fairly broad swath of the right …

  36. 86
    Hank Roberts says:

    > AMOC
    try Google Scholar, limit to 2012; the first 2 hits as of now are:

    Climate science: A grip on ice-age ocean circulation
    J Marotzke – Nature, 2012 – nature.com
    … Second, the AMOC in ocean-only models such as that used by Oka and colleagues has long been known to be overly sensitive to minute details entered into the simulations …

    Moored instruments show decadal drop in AMOC strength
    C Schultz – Eos, Transactions American Geophysical Union, 2012 – agu.org
    … They found that the supraglacial lakes move in a direction and with a speed that differs from ice shelf flow: parallel to the grounding … that AMOC will slow down as Earth’s temperatures rise due to anthropogenic warm- ing, which could have serious climate consequences for …

  37. 87
    Craig Nazor says:

    Observer:

    I have been an environmentalist since the 1960′s. I have never met a single environmentalist who supported government-subsidized flood insurance. Of course, back in the 1960′s, when the term “conservative” actually meant something, there were more environmentalists on both sides of the fence. In general, while “conservatives” vacillate on approval or disapporval of government-subsidized flood insurance (depending on where their investments are placed), through the years, environmentalists (who by now have been forced to the left) have consistently opposed such flood insurance:

    http://www.waterinfo.org/node/4182

    http://news.firedoglake.com/2012/06/29/environmentalists-dont-like-concessions-in-transportation-bill/

    http://www.chron.com/CDA/archives/archive.mpl/1992_1058545/flood-insurance-bill-brings-furious-battle-environ.html

    http://news.google.com/newspapers?nid=1798&dat=19810504&id=Qlw0AAAAIBAJ&sjid=T44EAAAAIBAJ&pg=6925,270616

    http://www.texasobserver.org/forrestforthetrees/texas-republicans-in-congress-flunk-on-the-environment

    It appears you are arguing from your own opinion, rather than from any factual basis. At any rate, it doesn’t matter, as others have said. With the current lack of any meaningful action to slow global warming, rising sea levels will put a quick end to government-subsidized flood insurance programs – just as soon as the party of denial comes to its senses, that is.

  38. 88
    observer says:

    Re, #87.

    I think I am in general agreement with the views set forth in #87. I think that many environmental organizations, perhaps a substantial majority, oppose subsidized flood insurance. Moreover, it is probably the case that many of the environmental organizations that do not have such a position have not thought about it. (I’m on the board of one such organization—we don’t have a position regarding flood insurance but, I think that, if we did have a position it would be in opposition to such subsidies.)

    However, environmentalists and the left are two different classifications.

    If one want’s to study this point carefully, I suggest classifying organizations into 4 categories left, left&environmental, right, right&environmental. Then calculate the frequency with with groups in each class support or oppose flood insurance. I think the non-environmental left would lag the non-environmental right.

    Two last observations—one a cheap shot.

    I. Flood insurance was pushed by Lyndon Johnson and was first enacted when he was president.

    II. (This is the cheap and misleading, albeit factually correct, observation.) The U.S. Senate voted out a flood insurance bill last Friday. All 19 votes against it were Republicans—including senators from those notoriously flood-prone states Idaho, Utah, and Arizonak. But it was also opposed by Graham and Rubio. See http://www.c-spanvideo.org/vote/102694.

    However, see http://insurancenewsnet.com/article.aspx?id=348881 for a sign that cui bono is a good guide to understanding strong support for flood insurance.

  39. 89
    Ed Beroset says:

    The Brunswick nuclear plant is located in Southport, NC and the reactor building is at an elevation of twenty feet. My recollection is that the design basis for this reactor (which happens to be of the same type as some of the Fukushima reactors) was a storm surge of 22 feet. There was a Senate hearing which looked at the risks of rising sealevel on domestic infrastructure at which the NRC was encouraged to study the risk specifically of rising sea level on nuclear plant design, but I can’t seem to locate any news item to indicate that this is indeed happening. Sound engineering practice would seem to call for a re-examination of design if the underlying assumptions have changed.

  40. 90
    s.b. ripman says:

    Scientists need to stress the fact that size matters and we’re dealing with enormous sizes.
    You fellows know that the volume of the World Ocean is around 3,100 million cubic miles, and its average depth is about 13,000 ft. (miles and feet used for American minds).
    Thus it’s small wonder that in the near future when the ocean warms even very slightly, and thermal expansion occurs, the sea level will rise a few feet (a tiny blip given the scales involved).
    Or that over time, ice sheets melting (average thickness 7,000 ft.) can cause the sea level to rise about 20 ft. for Greenland and 180 ft. for Antarctica (a very small amount given the vastness of the World Ocean).
    These relative sizes, combined with the fact that 90% of global warming is absorbed by the oceans, should be easy to depict pictorially or graphically, so that Americans can get it through their heads that this is happening.

  41. 91
    Jim Larsen says:

    79 Old Navy said, “I cannot think of worse place to conduct a study of sea level rise due to the tremendous natural variability. Why not conduct a sea level rise study of the Rock of Gibraltar and other relatively fixed shorelines? Places where the volatility is low.”

    Perhaps my experience is unusual, but I’ve found that perhaps 50% of all the common-sense snap-judgements I make with regard to science are 180 degrees off. There are so many variables, and the order of magnitude for each is essentially unknowable until one does the science. Common sense tells us the Earth is flat. Just look for yourself!

    (I’m still sitting on that PIOMAS post, waiting for the melt season to get going. I can’t see any way that the estimates are even remotely accurate. Fig 3 estimates 15,000 km3 by 2015 when last year was ~4. Sounds really wrong to me. So, my assumption is that the PIOMAS post is my Gibraltar. Interestingly, Hank said nobody was predicting an increase in sea ice – uh, well, figure 3 seems way explicit. Again, my assumption is that I’m missing something and the graph which says the CCSM4 mean for 2015 is ~15k means something other than what it “obviously” does. To me, it seems to mean that either CCSM4 is seriously flawed, PIOMAS volume estimates are way off, or the recent past has been an incredible outlier and we’re likely in for a huge increase in sea ice. Since nobody else sees it that way, I’m stuck…)

  42. 92
    Hank Roberts says:

    Jim Larsen says: 2 Jul 2012 at 1:22 PM “Hank said nobody was predicting …”
    What? Where?

  43. 93
    Unsettled Scientist says:

    Old Navy asked> “I cannot think of worse place to conduct a study of sea level rise due to the tremendous natural variability [of the NC coast]. Why not conduct a sea level rise study of the Rock of Gibraltar and other relatively fixed shorelines? Places where the volatility is low.”

    I’d like to address a misunderstanding that I think the subtext of this highlights.

    The question assumes we can only measure SLR using “marker on a rock”-type measurements. We have other means such as buoys and satellites.

    Places made of extremely solid rock, even (for the sake of argument) “erosion-proof” places would still not be suitable for measuring global sea level rise (SLR). That is a figure which must be built by taking evidence from many different places because SLR is not uniform along the world’s coastlines. It is not analogous to ice melting into a glass or water’s expansion as you heat a pot on the stove. For example, the currents make ice melt from the Antarctic impact some coastlines, but not others.

    So if one wishes to know about how SLR is going to impact the Carolina coast, regional studies must be done. The Regional Sea Level (RSL) is what people like public planners in NC need to look at, not the global SLR. If the RSL rise is greater than the global SLR, then that location is going to have to deal with the impacts of our rising oceans sooner than the rest of us.

    Because of this regional variation the ocean as a whole must be studied. One cannot just go find a solid rock somewhere and mark the high water point each day. That will only tell you about what is happening at that rock and could either over or underestimate the global average rise in sea level.

    So to summarise a direct answer: Studies in Gibraltar won’t help in NC much other than the piece they play in building our larger understanding. NC’s vulnerable coast increases the necessity of studying the region. That vulnerability extends inland and is not limited to the barrier islands.

  44. 94
    Unsettled Scientist says:

    More on the idea of Regional Sea Level issues.

    East Coast faces faster sea level rise Cities from North Carolina to Massachusetts see waters rising more rapidly

    “We have direct evidence of a hot spot stretching from Cape Hatteras in North Carolina to just above Boston,” says Asbury Sallenger Jr., an oceanographer at the U.S. Geological Survey’s St. Petersburg Coastal and Marine Science Center in Florida. “The area has an unusual sea level rise acceleration compared to the rest of the United States.”

    Climate change has, on average, raised the surface of the world’s oceans in recent decades by melting glaciers and causing seawater to expand as it warms. But the rise hasn’t been uniform, like water filling a bathtub. It has happened at different speeds in different places, thanks to wind patterns, currents and other regional factors that shape ocean surfaces.

  45. 95
    Craig Nazor says:

    Observer:

    I would say that those who support federally-subsidized flood insurance are those who either are invested in or represent those who are invested in flood-prone real estate. I think that “right” or “left” have little to do with it. You have given no evidence whatsoever (other than your own opinion) to prove otherwise.

    But I am still having a hard time understanding where you are coming from. What present-day organization would you charaterize as “right&environmental”? By “right,” I am assuming that you mean the current Republican agenda.

  46. 96
    Hank Roberts says:

    You can look this stuff up. It’s not simple, not just elevation or “flood plain” location: http://www.floodsmart.gov/floodsmart/
    Many flood risks depend on changes upstream or downstream and the maps change year to year. http://www.floodsmart.gov/floodsmart/pages/flooding_flood_risks/mapScheduleSearch.action?zipCode=&x=28&y=15

    You wouldn’t have any clue that, for example, upstream development had changed rainwater percolation rates increasing the risk of a flood in your location — or have any way to calculate that risk or price insurance on it — in a pure free market mythical universe. This is one of the reasons why people organize.

  47. 97
    Jim Larsen says:

    88 Observer noted that the 19 senators who voted against the flood insurance reform bill were Republicans. Assuming this is the same bill quoted above: “Several members of both parties agreed that a top priority of the bill is eliminating the red ink that the National Flood Insurance Program (NFIP) has generated over the past several decades. Members noted that the NFIP is nearly $18 billion in debt, and spoke in favor of the bill that would require the phasing in of actuarially sound rates for flood insurance policies, and phasing out taxpayer subsidized rates.”

    So, to make your self-described misleading point a bit less so, the bill ENDS taxpayer-subsidized flood insurance via what seems like a rational phase-out period. Thus, those 19 Republicans voted against ending subsidized flood insurance. Maybe they didn’t like the phase out period, or wanted to explicitly turn over the system to the private sector afterwards. Maybe they like things as they are/were. Guess you’d have to ask them…

    As to whether more right-wingers or left-wingers support subsidized flood insurance, perhaps a reasonable estimate would be the percentage of each who own or market or otherwise have an interest in property in a flood-prone area. You won’t find many Democrat real estate agents in Miami who would support the above bill. Nothing like good old self-interest to make most any capitalist go communist and vice-versa! This isn’t a right-left issue, but a special interest issue.

    This bill, along with work such as described in the OP showing the increasing risk over time, looks like it has the possibility to cause a tremendous long-term decline in value along the coasts. When your house is expected to be destroyed on a regular basis, insurance can be pricey.

    Hmm, perhaps this is going too far, but now that we’ve got the coastal dwellers paying for their own insurance, what about the billions for flood control? Shouldn’t New Orleans residents pay for their own dikes? Shouldn’t the decision about how much to pay for dikes (aka how high) be a local one? With insurance dangling lower rates for higher dikes, the market can handle the issue.

  48. 98
    sidd says:

    More expensive real estate gone: a foot of sea rise in two decades in California

    http://www.nap.edu/catalog.php?record_id=13389

    anyone wanna crunch the numbers for real estate financial losses from this one and Sallenger ? NPV of assumed income flows (taxes, bonds, mort_gages…) turning into losses from having to build protection or demolish ?

    developers are gonna squeal like pigs. so are their bankers.

    sidd

    P.S. apparently the word relating a lien on a property to a financial obligation is spam…

  49. 99
    Jim Larsen says:

    92 Hank said, ” “Hank said nobody was predicting …”
    What? Where?”

    Durn. I KNEW you were going to ask that and I STILL posted without digging through all the posts…

    Well, I looked for “Hank” on the PIOMAS thread, and found that you’re rather prolific! But I didn’t find the comment I was looking for. Sigh. I also looked for “Nobody” and got nothing. So, let me attribute my remembering you being who said it as great admiration for what you bring to this site. I suppose it was on another thread, and probably not you since you don’t remember it.

    Be that as it may, what do you make of fig. 3 in the PIOMAS post? What does it “really” say about sea ice predictions for 2015? My logic was – sea ice returns to norm quickly (low memory) – so within a few years the ice volume should be unlinked to current conditions and the median run becomes the prediction regardless of current conditions. Fig 3 shows median run of 15k in 2015. Thus, since none of the experts showed the slightest indication that either PIOMAS or CCSM4 aren’t pretty durn good, our current 4k is due to skyrocket. The numbers are just too far apart to say otherwise. All I’ve got is PIOMAS sucks, CCSM4 sucks, or sea ice is set to triple or quadruple in volume. What’s my error?

  50. 100
    Hank Roberts says:

    > what do you make of fig. 3

    Hang on, I’ll ask the guy on the next barstool over.
    Whoever he is, he’ll be as reliable as I would be interpreting scientists’ work for you.

    Oh, wait, there’s a better way: take my standard advice and apply it.

    Ask the scientists at the PIOMAS site, not some guy on a blog!

    Start with what they have posted on their website.
    Read the paper they link to.
    Ask questions the smart way.

    When scientists are unwilling to speculate beyond what they tell you they can do from what they know, that _is_ the answer.


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