[Coral-List] Atolls and SL rise

Bill Allison allison.billiam at gmail.com
Tue Oct 5 05:41:47 EDT 2010


Here is what the German public is being treated to:

http://www.spiegel.de/international/world/0,1518,707884,00.html

On Tue, Oct 5, 2010 at 2:09 PM, Richard Dunne <RichardPDunne at aol.com> wrote:

>  Dear Listers and Bill
>
> Bill makes a very valid point for the seasonal influences in the Maldives
> where (particularly in the northern islands) there is a significant
> difference as Han et al point out. However, further south in the Chagos for
> example, this is not the case. The Han et al model shows a lot of
> heterogeneity both overall and seasonally throughout the Indian Ocean which
> emphasises the regional nature of long term sea-level changes.
>
> Richard P Dunne
>
>
> On 05/10/2010 03:13, Bill Allison wrote:
>
>>
>> As I pointed out in my post of Sep 30, 2010, Han et al. (2010) also
>> suggested on page 549 that seasonal variation in sea level could have
>> significant effects.
>>
>> "However, statistically significant sea-level rise is shown during winter
>> in both ocean general circulation models and Simple Ocean Data Assimilation
>> data (Supplementary Fig. S2), which could have significant impacts on the
>> Maldives because of its low elevation." p. 549
>>
>> Factor in storm surge or a tsunami riding on the back of such variation
>> and the risk increases appreciably.
>>
>>
>>
>>  On Mon, Oct 4, 2010 at 7:41 AM, Richard Dunne <RichardPDunne at aol.com<mailto:
>> RichardPDunne at aol.com>> wrote:
>>
>>     Dear Paul and List
>>
>>    By casting aside the more recent evidence from Han et al 2010 (Nature
>>    Geoscience) into the category of "a little absurd" you fail to
>>    distinguish between regional sea-level rise and globally averaged
>>    effects, between analysis which incorporate regional ocean-atmosphere
>>    circulation changes and which do not, between examination of recent
>>    (from the 1960s up to 2008) rates of change, and those incorporating
>>    semi-empirical modelled and predicted events. These things cannot be
>>    easily resolved or selectively dismissed in this way.
>>
>>    Han et al. conclude "Our results indicate that warming-induced
>>    regional
>>    atmospheric circulation changes - although challenging for climate
>>    models, especially over the Indian monsoon region - should be
>>    considered
>>    seriously, together with thermal expansion, melting land ice and
>>    natural
>>    variability, to achieve reliable regional sea-level and climate
>>    prediction."
>>
>>    A recent comprehensive review of of sea-level rise by Cazenave &
>>    Llovel
>>    (Annual Reviews of Marine Science 2010) considers an earlier paper by
>>    Rahmstorf (2007) which like the recent Vermeer & Rahmstorf (2009)
>>    produced comparable values of between 50 and 120cm by 2100, describing
>>    it as "offering plausible ranges of future sea-level rise and an
>>    interesting alternative to still uncertain coupled climate model
>>    projections.".
>>
>>    Also, if it is indeed "widely accepted" as you say, that the IPCC AR4
>>    (AB1) scenario for future globally averaged sea-level rise is a
>>    serious
>>    underestimation then why for example do the eminent scientists of the
>>    Royal Society (Climate change: a summary of the science. Sept
>>    2010) not
>>    share these views? There is no evidence that they accept the large
>>    values that you cite, quite the contrary. They conclude that
>>    "Because of
>>    the thermal expansion of the ocean, it is very likely that for many
>>    centuries the rate of global sea-level rise will be at least as
>>    large as
>>    the rate of 20 cm per century that has been observed over the past
>>    century." and "There is currently insufficient understanding of the
>>    enhanced melting and retreat of the ice sheets on Greenland and West
>>    Antarctica to predict exactly how much the rate of sea level rise will
>>    increase above that observed in the past century for a given
>>    temperature
>>    increase."
>>
>>    This is, and remains an area of considerable uncertainty and
>>    controversy
>>    and I dare say will remain so until a reliable longer term dataset has
>>    accumulated. In the meantime we should be cautious to oversimplify the
>>    issues involved and close our minds to all the alternatives.
>>
>>    Richard P Dunne
>>
>>
>>
>>
>>    On 03/10/2010 05:08, Paul Blanchon wrote:
>>    > Dear Richard and list,
>>    >
>>    > The argument that some atolls  "may survive for generations"  and
>>    > should be considered for re-population seems just a little absurd,
>>    > regardless of the politics.
>>    > It is widely accepted that not only is the IPCC AR4 prediction of SL
>>    > rise a serious underestimation, but that over the last few decades
>>    > "...sea level has in fact risen 50% more than predicted by its
>>    > models..."  (see the illuminating climate-science blog at:
>>    >
>>    www.realclimate.org/index.php/archives/2010/03/ippc-sealevel-gate/
>>    <
>> http://www.realclimate.org/index.php/archives/2010/03/ippc-sealevel-gate/>).
>>
>>
>>    >
>>    > The IPCC underestimation has been the subject of several subsequent
>>    > publications which all conclude SL rise by 2100 will likely
>>    exceed one
>>    > meter: for example, Vermeer and Rahmstorf 2009 (PNAS 106:
>>    21527-21532)
>>    > predict average rates over the 21st century will be 8-18 mm/year.
>>    > Thus, as Chip Fletcher implies, the experience of Micronesians is
>>    > likely to be repeated in all low-lying coastal communities,
>>    regardless
>>    > of past or future regional variation.
>>    >
>>    > Re-population of any atoll would therefore seem to be an
>>    exceptionally bad idea.
>>    >
>>    > Saludos,
>>    > Paul.
>>    >
>>    > Paul Blanchon
>>    > Marine Geoscience Lab.,
>>    > Reef Systems Unit,
>>    > Institute of Marine Sciences&  Limnology
>>    > National Autonomous University of Mexico
>>    > Tel. +52  (998) 87-10009 Ext 166
>>    > _______________________________________________
>>    > Coral-List mailing list
>>    > Coral-List at coral.aoml.noaa.gov
>>    <mailto:Coral-List at coral.aoml.noaa.gov>
>>
>>    > http://coral.aoml.noaa.gov/mailman/listinfo/coral-list
>>    _______________________________________________
>>    Coral-List mailing list
>>    Coral-List at coral.aoml.noaa.gov <mailto:Coral-List at coral.aoml.noaa.gov>
>>
>>
>>    http://coral.aoml.noaa.gov/mailman/listinfo/coral-list
>>
>>
>>
>>
>> --
>> ________________________________
>> "reality leaves a lot to the imagination..."  John Lennon
>>
>


-- 
________________________________
"reality leaves a lot to the imagination..."  John Lennon



More information about the Coral-List mailing list