349
intrusion would be catastrophic in atolls, physically threatened in their existence beyond the
problems of climate refugees of their populations (Maldives, Bahamas, Kiribati). Some
argue on the persistence of atolls with reefs
growing up and rising in tandem with the sea
(Pala 2014 ). Nevertheless, there will be a delay
between the two phenomena, and reef accretion
during Holocene reveals less rates (Perry et al.
2013 ; Hubbard et al. 2014 ).
The rise in ocean temperature will cause
bleaching events and coral mortality during summer. Hoegh-Guldberg in 1999 predicted that
bleaching mortality would be very frequent in
2015 and each year in 2040. Since, our knowledge on the relationship between corals and their
zooxanthellae and characteristics of the zooxanthellae has made much progress with somme
adaptability (Logan et al. 2013 ; Palumbi et al.
2014 ). It appears that some coral species are less
sensitive to limited temperature anomalies
than others with also geographic variations
(McClanahan et al. 2007 ), and other species are
capable of adaptation or acclimatisation (Guest
et al. 2012 ; Logan et al. 2013 ; Palumbi et al.
2014 ). The latest report from the IPCC predicts a
rise in temperature, mean values, between 1.8
and 4 °C in 2100. A too rapid speed of temperature rise would not allow corals to adapt according to Donner et al. 2005 , and most of the
scientifi c papers indicate that there will be almost
yearly mortalities for the mid-twenty-fi rst century (Donner, 2009; Burke et al. 2011 ). Changes
in sea temperature and currents are expected to
redistribute the geographic distribution of fi sh
available for catch with a decrease in the tropics
which tend to be the most socioeconomically
vulnerable areas (Cheung et al. 2010 ).
Ocean acidifi cation is already evidenced by
a decrease of one-tenth of a pH unit over the
past century. It could not be stopped and would
decrease from 8.2 to 7.8 in 2100 representing a
decrease of 100 times faster than in the last
million years and a fi nal value that the ocean
has not been known for the last 20 million
years. The challenge is signifi cant because
experimental studies in laboratory or in natural
habitats where pH is less basic show much less
calcifi cation of benthic and pelagic organisms
with calcareous tests (Gattuso et al. 1998 ;
Langdon and Atkinson 2005 ; De’ath et al.
2009 ; Fabricius et al. 2011 ). Most studies agree
on an announcement published 15 years ago
(Kleypas et al. 1999 ) with the prediction that
the calcifi cation of organisms would be reduced
by a third in 2050.
The fi ght against the consequences of climate
change can only be taken at the worldwide level
for emissions of greenhouse gas. There is no way
for a country to fi ght whatever against the consequences of more intense cyclones, rising sea temperatures and ocean acidifi cation, all phenomena
that lead to degradation and affect coral reef resilience. Only the rise in sea level can be thwarted
in some countries able to deploy extremely
expensive works that do not own the majority of
small island technology.
7
Predictions of Climate
Change and Catastrophic
Ambiance
The future of coral reefs is disquieting in the context of global change with demographic pressure
which will increase, especially in coastal areas,
and predictions of climate change at global scale
although variable according to regions. This is
the reef ecosystem across the whole planet that
might be achieved. We would like to comment on
two aspects: predictions and science progress and
the ambiance of catastrophism.
7.1
Predictions and Science
Progress
How do we consider with objectivity scientifi c
statements and predictions which are published
over time and what credibility should we give to
present scientifi c explanations and prediction on
the future of coral reefs?
Health and Degradation of Coral Reefs: Assessment and Future
intrusion would be catastrophic in atolls, physically threatened in their existence beyond the
problems of climate refugees of their populations (Maldives, Bahamas, Kiribati). Some
argue on the persistence of atolls with reefs
growing up and rising in tandem with the sea
(Pala 2014 ). Nevertheless, there will be a delay
between the two phenomena, and reef accretion
during Holocene reveals less rates (Perry et al.
2013 ; Hubbard et al. 2014 ).
The rise in ocean temperature will cause
bleaching events and coral mortality during summer. Hoegh-Guldberg in 1999 predicted that
bleaching mortality would be very frequent in
2015 and each year in 2040. Since, our knowledge on the relationship between corals and their
zooxanthellae and characteristics of the zooxanthellae has made much progress with somme
adaptability (Logan et al. 2013 ; Palumbi et al.
2014 ). It appears that some coral species are less
sensitive to limited temperature anomalies
than others with also geographic variations
(McClanahan et al. 2007 ), and other species are
capable of adaptation or acclimatisation (Guest
et al. 2012 ; Logan et al. 2013 ; Palumbi et al.
2014 ). The latest report from the IPCC predicts a
rise in temperature, mean values, between 1.8
and 4 °C in 2100. A too rapid speed of temperature rise would not allow corals to adapt according to Donner et al. 2005 , and most of the
scientifi c papers indicate that there will be almost
yearly mortalities for the mid-twenty-fi rst century (Donner, 2009; Burke et al. 2011 ). Changes
in sea temperature and currents are expected to
redistribute the geographic distribution of fi sh
available for catch with a decrease in the tropics
which tend to be the most socioeconomically
vulnerable areas (Cheung et al. 2010 ).
Ocean acidifi cation is already evidenced by
a decrease of one-tenth of a pH unit over the
past century. It could not be stopped and would
decrease from 8.2 to 7.8 in 2100 representing a
decrease of 100 times faster than in the last
million years and a fi nal value that the ocean
has not been known for the last 20 million
years. The challenge is signifi cant because
experimental studies in laboratory or in natural
habitats where pH is less basic show much less
calcifi cation of benthic and pelagic organisms
with calcareous tests (Gattuso et al. 1998 ;
Langdon and Atkinson 2005 ; De’ath et al.
2009 ; Fabricius et al. 2011 ). Most studies agree
on an announcement published 15 years ago
(Kleypas et al. 1999 ) with the prediction that
the calcifi cation of organisms would be reduced
by a third in 2050.
The fi ght against the consequences of climate
change can only be taken at the worldwide level
for emissions of greenhouse gas. There is no way
for a country to fi ght whatever against the consequences of more intense cyclones, rising sea temperatures and ocean acidifi cation, all phenomena
that lead to degradation and affect coral reef resilience. Only the rise in sea level can be thwarted
in some countries able to deploy extremely
expensive works that do not own the majority of
small island technology.
7
Predictions of Climate
Change and Catastrophic
Ambiance
The future of coral reefs is disquieting in the context of global change with demographic pressure
which will increase, especially in coastal areas,
and predictions of climate change at global scale
although variable according to regions. This is
the reef ecosystem across the whole planet that
might be achieved. We would like to comment on
two aspects: predictions and science progress and
the ambiance of catastrophism.
7.1
Predictions and Science
Progress
How do we consider with objectivity scientifi c
statements and predictions which are published
over time and what credibility should we give to
present scientifi c explanations and prediction on
the future of coral reefs?
Health and Degradation of Coral Reefs: Assessment and Future