Transcript 2060-2069 projected max. monthly SST (pCO2=517)

Climate Change and Coral Reefs:
Long-term threats, challenges and opportunities
R.W. Buddemeier
Presentation to the meeting of the USCRTF
San Juan, Puerto Rico, October 2-3, 2002
Proposals for building on the strengths and successes of the
CRTF, its members, and existing and new collaborators to
successfully address the global threats to coral reefs posed by
climate change.
With the endorsement and support of the Ocean Biogeographic Information
System (OBIS) and Census of Marine Life (CoML) programs
Carbon Dioxide (CO2) in the atmosphere:
•Warms the planet by trapping heat (the greenhouse effect)
•Dissolves in the surface ocean water
-Making it more acidic, which
-Reduces the concentration of carbonate ion (CO3=),
-Slowing the rate of calcification of corals and other
producers of calcium carbonate
Result: two different but interactive reef stresses -- acute stress
from high temperature episodes, plus a growing chronic stress
due to reduced rates of organism growth and reef consolidation
Illustrations from the NCAR coupled ocean GCM and
geochemical models.---
Projecting the future of
the marine environment
Scenario B2 was used for the examples in this presentation -- through
2065, it is the most conservative of the IPCC Emission Scenario
Models (IPCC 2000) for the time course of atmospheric CO2.
Temperature Data
The past 20 years show
expansion of the
warmest areas of the
Western and Eastern
Pacific -- with shortterm high temperature
episodes causing coral
bleaching even outside
of those areas
1982-1991 Reynolds maximum monthly SST
1992-2001 Reynolds maximum monthly SST
Model SST results
The geographic
distribution of warm
areas is projected to
expand over the next
few decades -- but to
stabilize thereafter….
2000-2009 projected max. monthly SST (pCO2=375)
2020-2029 projected max. monthly SST (pCO2=415)
Although some
intensification continues
in the western Pacific,
tropical oceans have a
natural ‘thermostat’ that
is expected to cap the
ranges and values of the
highest temperature
classes
2040-2049 projected max. monthly SST (pCO2=465)
2060-2069 projected max. monthly SST (pCO2=517)
Calcification controls
Low CaCO3 saturation =
less calcification
The upper right-hand
figure represents the
low end of the normal
range of conditions
experienced by reefs
for the past several
million years.
Considerable change
has already occurred
(lower right), but reef
areas have not yet felt
the full impact.
Preindustrial aragonite saturation state (pCO2=280)
2000-2009 aragonite saturation state (pCO2=375)
As temperatures increase
outward from the
equatorial West Pacific
and stabilize, favorable
saturation state
conditions decrease with
an opposite pattern.
2020-2029 aragonite saturation state (pCO2=415)
The transect of US reef
MPAs in the Pacific
provides an ideal network
to monitor, predict and
understand the effects of
these unprecedented reef
environments.
2040-2049 aragonite saturation state (pCO2=465)
2060-2069 aragonite saturation state (pCO2=517)
Does “all marginal” mean doom and extinction?
Not necessarily -- there are numerous reef communities
in marginal habitats now. But almost certainly, the reef
communities of the future, and the management
techniques and MPAs they require, will have structures
and functions different from the ones we now know.
Necessary steps
Knowledge of species composition and population structures of
reef communities will be critical for predicting responses to climate
change, and for identifying and managing sustainable systems
Global clines in species richness of corals (Roberts et al. 2002)
Not all reefs are alike -- gradients of diversity as well as of
environmental conditions provide a natural laboratory to
understand and prepare for the effects of predictable change.
Pacific Refuges and Sanctuaries, on a map showing preindustrial ‘marginality’ risk
and 2060-2069 projected expansion of 18.4 deg isotherm (cool limit) in green.
•US Pacific refuges and sanctuaries are a network of nearly pristine reefs,
uniquely situated to enable both practical and theoretical understanding of
the effects of climate change on coral reefs.
•USCRTF has the opportunity to add to its existing successful activities a
long-term commitment to adaptive research, monitoring and management
that will nucleate an unprecedented depth and breadth of collaborative
work on solving the challenges of sustaining coral reef ecosystems.
Recent announcement: NSF 02-186
Biodiversity Surveys and Inventories, including:
Planetary Biodiversity Inventories -- a cooperative effort of
the NSF, the Alfred P. Sloan Foundation, and the ALL Species
Foundation
“The geographic or ecological scale of the project should constitute a
natural and compelling biological focus.”
“Included are very large-scale projects that can be competed in 5 years
or less, and also longer-term studies…”
“PBI attempts to empower international teams of scientists to
intensively inventory groups across geologic time and ecological space.”
“Because the oceans that dominate our planet are so seriously
undersampled, at least one award will be targeted specifically to a
marine group of organisms.”
Supplementary Information Slides
Addition of IPCC projections to the
observed changes produces an even more
dramatic shift for coming decades
•We have entered a “noanalog” period of earth history
•Trends will continue for
decades and are not easily
reversed
•Accelerated climate change is,
or soon will be, the overall
dominant source of stress for
coral reefs and other widelydistributed ecosystems
Northern hemisphere
temperature history and
projection, 1000-2100 AD
Generic richness of hermatypic corals. Contours show max number of genera likely to be found.
(Veron, 1986)
Figure 4a. Preindustrial marginality risk and 2060-2069
projected expansion of 18.4 deg isotherm in green.
Figure 4e. 2060-2069 projected marginality risk (pCO2=517)
Figure 4c. 2010-2019 projected marginality risk (pCO2=387)
Figure 4d. 2020-2029 projected marginality risk (pCO2=415)
Figure 4e. 2030-2039 projected marginality risk (pCO2=437)
Figure 4f. 2040-2049 projected marginality risk (pCO2=465)
Figure 4g. 2050-2059 projected marginality risk (pCO2=492)
Figure 4e. 2060-2069 projected marginality risk (pCO2=517)