[Coral-List] Fw: Chagos MPA - Continuing international dispute overboundaries

Bill Allison allison.billiam at gmail.com
Wed Sep 29 19:57:35 EDT 2010


Doug Fenner did point out that reefs and islands might keep up with
sea level rise and field work by Kench and Morner in their disparate
ways seems to support this. Doug qualified his remark by stating that
the ability of reefs and island to keep up will probably be inhibited
by ‘mass coral bleaching events killing corals faster than they can
recover their populations and acidification, slowing coral skeleton
growth and coralline algae growth.’ Some geophysicists (e.g., Peltier,
Mitrovica) have argued that the Maldives may have effectively been
rising for some time at a very slow rate and recently Han et al. (2010
Nat geosci 3;546) observed that the average sea level around the
Maldives does not seem to have increased, although positive variations
around the mean seem to pose a serious threat. It is not a simple
problem.

Even if the islands can in principle keep up with sea level rise and
we forget about the coastal alterations that are bound to occur during
the process, built structures seem to constitute a challenge. How
feasible does say, accretion by means of storm waves encroaching on
the ground floors of existing buildings seem? Island cities such as
Male no longer have a natural capacity for keeping up. Is land fill
behind sea walls a viable option?

In any case it a delicious irony that a nation at centre stage of the
sea level rise doom scenario is laying claim to territory rendered
uninhabited by other means.


On Wed, Sep 29, 2010 at 7:13 PM, Ulf Erlingsson <ceo at lindorm.com> wrote:
> Let me point out that the argument that atolls will sink due to sea
> level rise due to global warming fails to take into account the
> geomorphological mechanisms by which atolls are created and grow.
> They grow, slowly, through coral reef growth (as should be no news to
> anyone on this list), through littoral processes, and through
> chemical precipitation, i.e., when the water gets supersaturated with
> respect to CaCO2 the calcium is precipitated in layers on ooid sand
> grains, eventually building up large land masses such as the Bahamas.
>
> The problem is only when the sea level rises quicker than these
> processes can keep up with. However, the predicted rise in sea level
> is much smaller than the quickest and largest sea level rise in the
> recent past. See http://erlingsson.com/authorship/CIS2GOM.html
>
> Of course, that event did drown large areas that are now sea floor,
> but others managed to remain above water. A question of interest is,
> naturally, what lessons we can learn from that event.
>
> Ulf
>
> On 2010-09-28, at 22:41, Douglas Fenner wrote:
>
>> But those same atolls may not be
>>  inhabited much longer, due to sea level rise.
>
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________________________________
"reality leaves a lot to the imagination..."  John Lennon



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