[Coral-List] Are atolls doomed or can atolls grow as fast as sea level rise?

[Robert W Buddemeier]

*Re:  Atoll resilience in the face of rising sea level*



The article on this topic referenced by Doug Fenner fails to address some
significant considerations.

It may be true that atolls as landforms will accrete at a rate comparable
to sea level rise (SLR). That does not mean that the accretion process will
support continued human habitation, which I think is the real concern.

Humans live on the supratidal surface of the atoll – which must also be
high enough or protected enough to sustain infrastructure, agriculture, and
water resources.

In order to maintain the necessary elevation above sea (or high tide)
level, new sediment must be deposited on top of the existing surface, and
reasonably uniformly distributed across the usable area.

Since sediment is produced subtidally, a substantial amount of energy is
required to lift it onto and distribute it over the atoll surface.
Realistically, this means a major storm surge, large enough to wash over
most of the island surface and carry a lot of sediment with it.

Overwash by high energy, sediment-bearing salt water will damage or destroy
structures, contaminate soil and groundwater, and kill or damage all but a
few types of vegetation.  Recovery is unlikely to occur on a time scale
consistent with continued or immediate human habitation.

Even if that were not the case there is another major concern.  Sea level
rise is continuous, whereas major atoll-building storms are highly episodic
– and rarely occur in some locations.  Current SLR is 0.12-0.14 inches per
year, and expected to increase. I think that the return interval for
overwash events is well in excess of a century for most atolls.  For atoll
inhabitants, it looks like a choice between slow displacement and rapid
devastation, with no very good idea of the time constants for either.

Advancing the idea that atolls, *as human habitations*, can naturally keep
up with sea level rise risks allowing governments to assume that there
needs to be no provision of rescue or refuge for current and future atoll
dwellers.

How many of the people reading this would be willing to commit to living
indefinitely on an atoll even if they knew the carbonate production of the
surrounding water was theoretically adequate to “grow” the islands at a
rate equal to or greater than SLR?



Robert W (Bob) Buddemeier

On Tue, Dec 26, 2023 at 1:04 PM Douglas Fenner via Coral-List <
coral-list at coral.aoml.noaa.gov> wrote:

> Rethinking atoll futures: local resilience to global challenges
>
> https://www.cell.com/action/showPdf?pii=S0169-5347%2823%2900298-7
>
> open-access
>
> Cheers, Doug
>
> --
> Douglas Fenner
> Lynker Technologies, LLC, Contractor
> NOAA Fisheries Service
> Pacific Islands Regional Office
> Honolulu
> and:
> Coral Reef Consulting
> PO Box 997390
> Pago Pago, American Samoa 96799-6298  USA
>
> Fossil fuel air pollution kills 5 million people world-wide per year
>
> https://www.yahoo.com/news/research-shows-disturbing-between-millions-200000257.html
>
> World's richest 1% emit as much as 5 billion people
> https://makerichpolluterspay.org/climate-equality-report/
>
> Huge expansion of fossil fuels planned, will be very destructive
>
> https://www.theguardian.com/environment/2023/nov/08/insanity-petrostates-planning-huge-expansion-of-fossil-fuels-says-un-report
>
> "without policy changes, the world will heat up enough by the end of the
> century that more than 2 billion people will live in life-threatening hot
> climates"         Will you be in that area???
>
> https://www.yahoo.com/news/scientists-sounding-alarm-dangerous-problem-123000792.html
>
> World subsidies for fossil fuels reached an all-time high of over $1
> TRILLION in 2022, the last year for which data is available.  The subsidies
> MUST end.
>
>
> https://blogs.scientificamerican.com/observations/fossil-fuel-subsidies-must-end/
> _______________________________________________
> Coral-List mailing list
> Coral-List at coral.aoml.noaa.gov
> https://coral.aoml.noaa.gov/mailman/listinfo/coral-list
>