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

[Richard Dunne]

  Stoddart has published about cyclones in the Indian Ocean. In his 
paper (Stoddart 1971 Symp zool Soc Lond No 28:3-38) he writes "Equally 
important in reef physiography is the distribution of tropical cyclones 
(Fig 6). These are almost absent from the zone between 6 deg N and 5 deg 
S and are strongly concentrated in the Bay of Bengal, the Arabian Sea, 
and the southwest Indian Ocean."

The Chagos are between about 5-7 deg S. In Stoddart's Figure 6 there is 
only one cyclone track (of several hundred) which appears to cross the 
Chagos and the Admiralty Pilot only contains a record of one cyclone in 
1891.

This would accord with the findings of the Foreign Office Report in 2002 
"FEASIBILITY STUDY FOR THE RESETTLEMENT OF THE CHAGOS ARCHIPELAGO". The 
consultants examined the wind speed record from Diego Garcia between 
1973 to 2002 and only found a maximum recorded wind speed of 40mph (35 
knots) during the 29 years which corresponds to the lower boundary of 
the tropical storm category .   They concluded that it was unlikely that 
a cyclone had passed directly over Chagos during those 30 years. 
Generally the wind speeds in the Chagos region tend to be low. Similarly 
they found that the tide record for the 12 year period from 1988 to 2000 
showed only a variation of 10cm due to wind and waves, indicating no 
storm surges. Their cyclone and storm tracks again show that the Chagos 
escaped all storms between 1980 and 2002.

Although it would only require a small northern shift (2 to 3 degrees) 
in the boundary of the cyclone belt for the Chagos to be impacted, there 
is no evidence from the IPCC that this might occur.

Richard P Dunne

On 30/09/2010 13:17, Magnus Johnson wrote:
> It's not an area I know loads about (and I don't think it has much to do
> with the morals of ethnic cleansing of Chagos) but isn't there the added
> problem that with increased temperatures the frequency of hurricane type
> events is going to increase ->  reefs would need to accrete at a faster
> rate to compensate?  Or would more frequent events lead to higher rates
> of coral substrate formation?
>
> -----Original Message-----
> From: coral-list-bounces at coral.aoml.noaa.gov
> [mailto:coral-list-bounces at coral.aoml.noaa.gov] On Behalf Of Douglas
> Fenner
> Sent: 30 September 2010 00:10
> To: Ulf Erlingsson; coral-list at coral.aoml.noaa.gov
> Subject: Re: [Coral-List] Fw: Chagos MPA - Continuing
> internationaldisputeoverboundaries
>
> But as I tried to point out in my message, the best available scientific
>
> evidence now clearly predicts that in the future mass coral deaths due
> to
> coral bleaching will occur, and ocean acidification and reduced calcium
> carbonate saturation will greatly reduce inorganic precipitation (ooid
> precipitation is as far as I know a major factor only in the Bahamas
> currently, though the Yucatan Penninsula and parts of Florida may have
> been
> built largely of them, that was a long time ago.  Geologists may want to
>
> clarify that.).  Reef calcification rates will drop dramatically.  I
> think a
> consequence of these events will be that reef growth will slow
> substantially, and very likely won't be able to keep up with sea level
> rise.
>      Net effect is that yes, if current conditions continued, atolls
> should
> be able to keep up with current sea level rise.  But I believe there is
> every reason to predict that in the future, perhaps less than 50 years
> down
> the road, they won't be able to.  And won't again for a very, very long
> time.  Atolls that are currently inhabitable will likely continue to be
> so
> for a few decades, but are likely to be increasingly more difficult to
> live
> on with time.   Doug
>
>
> ----- Original Message -----
> From: "Ulf Erlingsson"<ceo at lindorm.com>
> To:<coral-list at coral.aoml.noaa.gov>
> Sent: Wednesday, September 29, 2010 4:13 AM
> Subject: Re: [Coral-List] Fw: Chagos MPA - Continuing international
> disputeoverboundaries
>
>
>> 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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