348
year in some places; these aggregations are
declining in both the Indo- Pacifi c and the
Caribbean (Russell et al. ( 2014 ).
5
The Condition of Reefs
from Global to Regional
The scientifi c coral reef community was asked in
the early 1990s by intergovernmental organisations (United Nations Environment Program,
Intergovernmental Oceanographic Commission,
World Meteorological Organisation, International
Union for Conservation of Nature) to launch a
long-term monitoring system on coral reefs
related to climate change. At that time, scientists
believed that the most important cause of future
degradation of coral reefs would be the demographic pressure and development which was
increasing considerably since 50 years. Meetings
from 1990 to 1993 (IOC reports) and in Panama
in 1996 led to the constitution of the Global Coral
Reef Monitoring Network (GCRMN) headed by
Clive Wilkinson who published the fi rst ‘Status
of Coral Reefs of the World’ in 1998, and others
have been regularly published. These reports
contributed largely to the sensibilisation of politicians and correlatively through the International
Coral Reef Initiative to the development of coral
reef science all over the world. About 20 % of the
world’s reefs are considered too severely
destroyed or disturbed to regenerate, and 35 %
are at risk of substantial deterioration in the years
to come (Wilkinson 2008 ). Nothing better than a
map can give a general picture of the health of the
coral reef ecosystem in the world. The map
(Fig. 1 ) from the World Research Institute (Burke
et al. 2011 ) indicates coral areas where risks of
degradation are impending: Southeast Asia, the
Caribbean and East Africa with a total of more
than 60 % of reefs. This is mainly due to demographic pressure and development. It is noteworthy that in central Pacifi c, far from continents and
with less population pressure, the reefs are less
threatened and relatively healthy (Salvat et al.
2008 ; Burke et al. 2011 ; Chin et al. 2011 ).
6
Climate Change
and Coral Reefs
We will not address the causes of climate change
and will retain its main consequences and predictions for the coral reef ecosystem.
Cyclones would not be more frequent than in
the previous decades, but their intensity will be
greater, levels 4 and 5 on the Saffi r-Simpson
scale in part due to a higher temperature of
ocean waters. This phenomenon has already
been observed during the recent decades (Hoyos
et al. 2006 ; Elsner et al. 2008 ) and would continue with perhaps more intensity (Knutson
et al. 2010 ). However, these predictions vary
according to regions. It is clear that the occurrence of more violent and destructive cyclones
disrupts reefs especially with the synergy that
can be caused by other disrupting events of natural or anthropogenic origins (Salvat and
Wilkinson 2011 ).
Rising sea level is already underway with an
average of just less than 2 mm per year since
1960. It was predicted at + 18–59 cm by 2100
according to the IPCC report in 2007. It is much
revised upwards in the report of 2013 and is
expected to be a minimum of 0.5–1 m. The rate
of accretion of reefs since the last Ice Age and
during the sea level rise was about 2 cm/year
and sometimes greater (Montaggioni 2005 ;
Camoin et al. 2012 ) which is compatible with
what would occur with the prediction of sea
level increase related to climate change worst
scenario. We must thus distinguish what is benefi cial or harmful to coral reefs on the one hand
and humanity on the other. For coral reefs, a sea
level rise is rather good news because they will
grow upward and they will expand after the
fl ooding of intertidal reef fl ats and colonisation
of coastal areas, but some negative factors
would also occur such as sedimentation and
turbidity (Hopley and Kinsey 1988 ; Storlazzi
et al. 2011 ). For people in coastal and low-lying
islands and their infrastructure, it is quite different, and the consequences will be disastrous
(IPCC 2013 , 2014 ). Land loss and saltwater
B. Salvat
year in some places; these aggregations are
declining in both the Indo- Pacifi c and the
Caribbean (Russell et al. ( 2014 ).
5
The Condition of Reefs
from Global to Regional
The scientifi c coral reef community was asked in
the early 1990s by intergovernmental organisations (United Nations Environment Program,
Intergovernmental Oceanographic Commission,
World Meteorological Organisation, International
Union for Conservation of Nature) to launch a
long-term monitoring system on coral reefs
related to climate change. At that time, scientists
believed that the most important cause of future
degradation of coral reefs would be the demographic pressure and development which was
increasing considerably since 50 years. Meetings
from 1990 to 1993 (IOC reports) and in Panama
in 1996 led to the constitution of the Global Coral
Reef Monitoring Network (GCRMN) headed by
Clive Wilkinson who published the fi rst ‘Status
of Coral Reefs of the World’ in 1998, and others
have been regularly published. These reports
contributed largely to the sensibilisation of politicians and correlatively through the International
Coral Reef Initiative to the development of coral
reef science all over the world. About 20 % of the
world’s reefs are considered too severely
destroyed or disturbed to regenerate, and 35 %
are at risk of substantial deterioration in the years
to come (Wilkinson 2008 ). Nothing better than a
map can give a general picture of the health of the
coral reef ecosystem in the world. The map
(Fig. 1 ) from the World Research Institute (Burke
et al. 2011 ) indicates coral areas where risks of
degradation are impending: Southeast Asia, the
Caribbean and East Africa with a total of more
than 60 % of reefs. This is mainly due to demographic pressure and development. It is noteworthy that in central Pacifi c, far from continents and
with less population pressure, the reefs are less
threatened and relatively healthy (Salvat et al.
2008 ; Burke et al. 2011 ; Chin et al. 2011 ).
6
Climate Change
and Coral Reefs
We will not address the causes of climate change
and will retain its main consequences and predictions for the coral reef ecosystem.
Cyclones would not be more frequent than in
the previous decades, but their intensity will be
greater, levels 4 and 5 on the Saffi r-Simpson
scale in part due to a higher temperature of
ocean waters. This phenomenon has already
been observed during the recent decades (Hoyos
et al. 2006 ; Elsner et al. 2008 ) and would continue with perhaps more intensity (Knutson
et al. 2010 ). However, these predictions vary
according to regions. It is clear that the occurrence of more violent and destructive cyclones
disrupts reefs especially with the synergy that
can be caused by other disrupting events of natural or anthropogenic origins (Salvat and
Wilkinson 2011 ).
Rising sea level is already underway with an
average of just less than 2 mm per year since
1960. It was predicted at + 18–59 cm by 2100
according to the IPCC report in 2007. It is much
revised upwards in the report of 2013 and is
expected to be a minimum of 0.5–1 m. The rate
of accretion of reefs since the last Ice Age and
during the sea level rise was about 2 cm/year
and sometimes greater (Montaggioni 2005 ;
Camoin et al. 2012 ) which is compatible with
what would occur with the prediction of sea
level increase related to climate change worst
scenario. We must thus distinguish what is benefi cial or harmful to coral reefs on the one hand
and humanity on the other. For coral reefs, a sea
level rise is rather good news because they will
grow upward and they will expand after the
fl ooding of intertidal reef fl ats and colonisation
of coastal areas, but some negative factors
would also occur such as sedimentation and
turbidity (Hopley and Kinsey 1988 ; Storlazzi
et al. 2011 ). For people in coastal and low-lying
islands and their infrastructure, it is quite different, and the consequences will be disastrous
(IPCC 2013 , 2014 ). Land loss and saltwater
B. Salvat