Rising Sea Levels Will Isolate People Long Before They’re Underwater

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Yves here. The matter of actual balkanization due to higher sea levels goes well beyond separation, even though that focus in this article helps make the point more vivid. At least in the US, there are many waste treatment and power plants that will be damaged in storm surges even if they are not soon inundated. Yet pretty much everyone is in business as usual mode. Doing anything remotely adequate requires a level of social cohesion and organizational capability that seems lacking across the world.

By Brian Owen. Originally published at Hakai; cross posted from Yale Climate Connections

The Chignecto Isthmus — the low marshy strip connecting New Brunswick and Nova Scotia — may be one of the most vulnerable places in Canada to sea level rise. At just 21 kilometers wide, the interprovincial land bridge is battered on its southwestern flank by the famously extreme tides in the Bay of Fundy. Protected by a network of earthen dikes first constructed in the 1600s, “the tops of the dikes are only a little higher than the spring high tides,” says Jeff Ollerhead, a coastal geomorphologist at Mount Allison University, located in Sackville, New Brunswick, at the western end of the isthmus. “If we have a big storm,” he says, “water will go over the dikes.”

When scientists and the public fret about sea level rise, they mostly focus on when and where communities will be permanently flooded. But there’s another consequence of rising seas that will affect many more people much sooner: getting cut off from roads and other critical infrastructure. It’s a threat that society has not paid nearly enough attention to, says Allison Reilly, a civil engineer at the University of Maryland.

The flood-prone Chignecto Isthmus shows what’s at stake. Hidden behind the barely sufficient dikes are reams of vital infrastructure: the Trans-Canada Highway, a Canadian National Railway line, multiple electrical transmission lines and fiber-optic cables, a wind farm, and agricultural land.

Though it’s unlikely the Chignecto Isthmus will be fully flooded any time soon — a disastrous outcome that would sever the link between New Brunswick and Nova Scotia — disruptions from storm-related flooding are becoming more common. That’s bad news for people like Ollerhead, who frequently cross the isthmus to get to medical appointments, access the international airport in Halifax, Nova Scotia, or even take shopping trips to Ikea. At a broader scale, temporary flooding of the highway or rail line could disrupt activity in the Port of Halifax, a major economic driver for the region.

In a new paper, Reilly and her colleagues show the breadth and pace of the isolation threat. Inspired by her work on the eastern shore of Maryland, where people already need to adjust their travel and work schedules to account for tides that frequently swamp roads, Reilly and her colleagues calculated that, with one meter of sea level rise, twice as many people across the coastal United States will be isolated than will be inundated. “People who live [three meters] above sea level, their house might be OK,” she says. “But that doesn’t mean they will be reliably able to get to the grocery store.”

While sea level rise is often considered a problem for the far future, Reilly says people will start getting isolated much sooner. “It’s very possible that we could see that in our lifetimes.”

Worse still, many places currently considered at low risk of sea level rise suddenly become much more vulnerable when isolation is taken into account, Reilly says. While planners know that low-lying Florida will be severely inundated, Maine, with its high rocky coasts, is generally thought to be at low risk. But Reilly’s work shows many Mainers are vulnerable to being cut off by flooding in coastal communities and river valleys.

This far more immediate effect of rising seas needs to become part of the broader planning process, says Reilly — both in terms of the adaptations and protections we build and also in how we prepare for the pending wave of climate migrants as people leave places where the quality of life has become too burdened by sea level rise.

That kind of planning is starting to happen around the Chignecto Isthmus, where the New Brunswick and Nova Scotia governments are considering a variety of plans to raise or replace the dikes. For Ollerhead, that work can’t start soon enough.

“It will take a lot of sea level rise before Nova Scotia becomes an island, but you could have a storm that cuts off the major transportation links for days, weeks, or months,” he says. “It’s nearly impossible to predict when, but it will happen eventually.”

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  1. Steve H.

    > cuts off the major transportation links for days, weeks, or months,

    And when that happens is likely to be the most inopportune time, as when the grid goes down in a heat wave.

    Recently in my neighborhood in Indiana:
    June 28: Canadian wildfire smoke at Very Unhealthy levels.
    June 29: Derecho blasts 70 mph winds, trees down, power out.
    June 30: Our power still out.
    July 1: Our power back on, not for half the neighborhood, 96′ heat index.
    July 2: Power back up for everyone.
    July 5: Microburst with winds as strong as derecho, more trees down, power out for half the neighborhood.

    It’s been a busy week.

  2. Giandavide

    the sea level is risening much more slower than the dollar is losing purchasing power. if the sea rise by a meter there will be lot of time to prepare for that. but now a bus stop or a public toilet in usa can cost more than a billion dollar, and with this tendency going on it’s pratically impossible than by 10 years the usa will be able to rebuild the infrastructures, everything will costs too much. there won’t be no roads for groceries not just in coastal cities, but everywhere

  3. Phil R

    Must be projecting one hell of a sea level rise. I’d like to know which wind farm the author is referring to. The two closest wind farms in New Brunswick (at least that I could find listed) are both at elevations of over 1100-1200 feet. Also, the elevation of the TC Highway is over 10 feet for the entire length of the highway across this area, except for a small section where it crosses a creek in the area of Cole’s Island. And I’m sure the Canadian highway authorities have the capability of raising this section if they need to (heck, they built a highway all the way across Canada). Sounds like another exaggerated scare story.

    1. Don Cafferty

      “Sounds like another exaggerated scare story.” I apologize for being contradictory but the story is quite realistic. I have lived in this affected area for 2 decades and have witnessed the flooding that is already occurring. What we are also witnessing at the same time is coastal erosion. Those dikes referenced in the article have also experienced erosion. I would suggest that the article is understated. In one of the quotes, there is a promise that there might be a grocery store except for the road. I live on high ground but my realization is that not only are the roadways challenged so is the grocery store.

      While the federal and provincial governments have now recognized the threat of sea level rise, I would suggest that some of the municipal governments have not. Municipal planning does not extend far enough in foresight to recognize the threat. As well, the federal and provincial governments base their plans and expectations on the “official” estimate of sea level rise, the infamous “one metre”. Among the large number of forecasts for sea level rise, one metre is an extremely shallow estimate in the range of estimates. Governments are seriously underestimating the risk by pin-holing one number without recognizing the large variance in estimates.

      Attention in the article is on the isthmus between New Brunswick and Nova Scotia which covers a very large area. With the flooding that is expected, Nova Scotia becomes separated from New Brunswick and is an island if only for a few days. However, in worse case scenarios the separation is permanent. In (very) worse case scenarios, the access to the bridge from New Brunswick to Prince Edward Island is underwater at both ends. Beyond the isthmus, Southeast New Brunswick can experience sea level rise from 3 directions: the Bay of Fundy; the Northumberland Strait; and, the tidal rivers sourced from the Bay and Strait. The City of Moncton does not see it coming!

      1. Phil R

        Thanks for your courteous reply from someone who lives in the area, and no need to apologize for being contradictory, I learn by hearing other people’s views.

        Part of my main point, although it probably wasn’t clear, was that this was a somewhat jaded review of a paper in Nature Climate Change that is paywalled and I don’t have access to (and am not going to pay for). My point about the “scare story” comment was that the author specifically mentioned some important infrastructure as being threatened when even a most cursory review shows it’s not, at least not any time in the next century.

        Google Earth may not be survey level accuracy for topographic elevations, but it’s pretty close for a reference. Except for some low-lying areas in the coastal zone at the head of the Bay of Fundy, most of the isthmus appears to be at elevations exceeding 10-20 feet and won’t be subject to flooding or inundation any time soon. I don’t understand your comment regarding the city of Moncton because, except some low-lying flood plain areas just along the river most of the city appears to be at an elevation mostly greater than 75 feet.

        I don’t deny that coastal flooding can be a problem that should be addressed, but I do have a problem with the need at times for authors to grossly exaggerate a problem just to draw attention to it. Nova Scotia will not become an island unless the Greenland ice sheet melts.

        1. Don Cafferty

          There is no exaggeration. Visible evidence speaks otherwise. Between Dorchester N.B. and Memramcook, Highway 106 and the train tracks run alongside the river. The highway has been closed many times during the last number of years due to flooding. The train tracks are a bit higher and have yet to be flooded; however, they are clearly in danger. In Sackville N.B, flooding has been a problem in particular areas. When flooding occurs, people need to make significant and time consuming detours.

          Moncton has a waterfront that has experienced erosion from the river. At the highest of current tides, water level rises surprisingly close to roads over bridges. The threat to Moncton is directly from the river. The indirect threat for Moncton is the large number of people in the broader area who may become displaced. Moncton is the largest destination in southeast N.B. and hence the direction that people will seek.

          I am not an expert but suggest that you may be too focussed on rise and elevation. Fredericton N.B. may or may not be a good example. It does not seem to take much of a rise in the river for the downtown to flood. Water does not have to flow over but can come up underneath in land adjacent to the river because the land and soil have become saturated. The spread of water is far greater than its rise.

  4. Bart Hansen

    Saw the approval of a down payment* of 7 billions for a new tunnel between Jersey and NYC. That money would better be spent toward slowly moving people in NYC to higher ground.

    * Eventual cost: Sky’s the limit.

  5. ambrit

    Mr. Cynic says that the more cost effective, (and everything is financially oriented in this Neo-liberal Paradise of ours,) solution for the sea level rise “problems” is The Jackpot. Fewer people means a lower load on infrastructure, and also, only those of “acceptable” socio-economic class will be able to move out of harm’s way.
    Neo-liberal Darwinism.
    To mangle a trope; “Don’t worry, be rich.”

  6. Jason Boxman

    I’d considered that with climate change, it might be that entire regions and left to their own devices as services are withdrawn. Perhaps like New Orleans after Katrina, but on a slower scale, or areas of Detroit that are simply abandoned by the state by and large. I suppose we’ll also have uninhabitable zones, populated only by those that the elite abandoned ages ago, because there’s no where affordable to live.

    1. Rolf

      I agree. In the US, this abandonment is by far the more likely scenario, unless there is very significant political change.

      The evidence for this is clear, as oft-repeated in these pages: “COVID was the pop quiz, and climate change [SL rise, drought, etc.] is the final exam“. After less than a year in office, Biden wrings his hands, insisting no national COVID strategy is possible, it’s up to the States (patchwork and piecemeal). And then … “COVID is over!“, an ever-tearful Walensky resigns, and … we’re done, because … Ukraine! So, no effective national strategy: ventilation and air quality in schools, hospitals, masking in public places such as airports, nope, nope, nasal viricides, prophylaxis … nope, not interested. It’s not because Americans don’t know how or can’t (we got used to seat belts, after all), but because constructing a truly effective national COVID strategy is utterly at odds with neoliberal objectives. So, instead? Russia! Taiwan! OMG China! And an obedient media moves in lockstep. And what of Flint? East Palestine? These disasters serve primarily as video media entertainment. Months or even just weeks afterwards, the lives of families involved are changed forever, and they rely on neighbors and local resources only.

      The response to AGW-associated disasters will be the same. This is after all, the neoliberal way. To the average citizen: “sorry [not sorry], you’re on your own“. To the donor class, “no worries, we’ve got your back“. But, hey, the Dems will fight for you (whatever that means), and Ukraine is winning! Right?

    2. scott s.

      Judging by home prices in Uptown New Orleans, I would say the elite are not abandoning the city at this point.

  7. The Rev Kev

    You would think that with the rising of the seas that it would be evenly done and would just follow the lines of the coastline. Maybe not. Some time ago I checked on my part of the world at a website where you could set whichever height that you wanted for future sea levels and see which areas would be most affected. What I found was that the major incursion seemed to be centered around creeks and rivers and if what I found was true, then you would expect that these inland rivers and creeks as they flood would cut off whole communities.

  8. Dan

    Jake Bittle’s book “The Great Displacement” illustrates scenarios such as this that are already happening in the US. An excellent read and also provides some perspective on the socioeconomic problems associated with coming up with solutions.

  9. sharonsj

    The 2004 and 2015 Pentagon reports on climate change are even scarier. These are public documents, so I recommend reading them. And I also recently saw a prediction that 1/3 of the world’s population could die off….

    We had a severe storm here that forced the Susquehanna River out of its banks. My small town was cut off at one end because the only east-west road in the upper part of Pennsylvania was impassible. It also stopped the railroads from running since the tracks were underwater too. If I tried driving five miles in the opposite direction, I would have hit a different section of the road underwater. So, yeah, getting to a supermarket would be difficult.

  10. Jeremy Grimm

    The storm drainage in most cities was designed to handle amounts and rates of rainfall estimated around the time the storm drainage was built. As the patterns of rainfall shift, the storm drains will overflow resulting in flooding to counterpoint and complement road blockage impacts of surges from the rising seas and the flooding of rivers and streams. Time to trade that electric car in your garage for a hovercraft for commuting to work and running errands.

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