THE CORAL TRIANGLE AND CLIMATE CHANGE: ECOSYSTEMS, PEOPLE AND SOCIETIES AT RISK
←
→
Page content transcription
If your browser does not render page correctly, please read the page content below
THE CORAL TRIANGLE AND CLIMATE CHANGE: ECOSYSTEMS, PEOPLE AND SOCIETIES AT RISK THIS REPORT IS A SUMMARY OF A COMPREHENSIVE STUDY INVOLVING OVER 20 EXPERTS AND BASED ON 300 PEER-REVIEWED SCIENTIFIC ARTICLES. THE FULL REPORT PLUS REFERENCES IS AVAILABLE ONLINE AT: www.panda.org/coraltriangle
The Coral Triangle is defined by marine zones containing at least 500 species of reef-building coral. The Coral Triangle supports livelihoods and provides income and food security, particularly for coastal communities. Resources from the area directly sustain more than 100 million people living there. Authorship team: Ove Hoegh-Guldberg, Hans Hoegh-Guldberg, John E. (Charlie) Veron, Alison Green, Edgardo D. Gomez, Janice Lough, Melanie King, Ambariyanto, Lara Hansen, Josh Cinner, Geoff Dews, Garry Russ, Heidi Z. Schuttenberg, Eileen L. Peñaflor, C. Mark Eakin, Tyler R. L. Christensen, Michael Abbey, Francis Areki, Rosemary A. Kosaka, Alexander Tewfik, Jamie Oliver.
The
Coral
Triangle
Number of Coral Species
First published in May 2009 by WWF Australia © WWF Australia GPO Box 528 Sydney NSW Australia Tel: +612 9281 5515 Fax: +612 9281 1060 ISBN number 978-1-921031-35-9 WWF and The University of Queensland would like to thank the following organisations for their support of this report: Coral Reef Targeted Research Project (www.gefcoral.org) James Cook University ARC Centre for Excellence in Coral Reef Studies Silliman University Australian Institute of Marine Sciences The Nature Conservancy EcoAdapt United States National Ocean and Atmospheric Administration Economic Strategies University of Diponegoro Center for Ocean Solutions, Stanford University University of Melbourne WorldFish Center University of the Philippines THE MANUSCRIPT CONTENTS ARE SOLELY THE OPINIONS OF THE AUTHORS AND DO NOT CONSTITUTE A STATEMENT OF POLICY, DECISION, OR POSITION ON BEHALF OF THE ORGANISATIONS LISTED ABOVE. Citation of this report: Hoegh-Guldberg, O., Hoegh-Guldberg, H., Veron, J.E.N., Green, A., Gomez, E. D., Lough, J., King, M., Ambariyanto, Hansen, L., Cinner, J., Dews, G., Russ, G., Schuttenberg, H. Z., Peñaflor, E.L., Eakin, C. M., Christensen, T. R. L., Abbey, M., Areki, F., Kosaka, R. A., Tewfik, A., Oliver, J. (2009). The Coral Triangle and Climate Change: Ecosystems, People and Societies at Risk. WWF Australia, Brisbane, 276 pp. Full report is available at: www.panda.org/coraltriangle Designed by www.threeblocksleft.com.au Photography by Ove Hoegh-Guldberg, University of Queensland (except where indicated)
Contents About This Report 2 Executive Summary 4 The Imperative: Which Future Will We Choose? 6 Worst case (A1B): Failure to reduce climate change amid escalating local threats 8 Best case (B1): Decisive action on climate change while building sustainable communities 10 The Global Challenge: Climate Change 14 Impacts have already begun 14 Small changes have big impacts 18 The Coral Triangle: The Earth’s Storehouse of Biological Diversity 20 Evolution’s cauldron 20 An urgent conservation priority 21 Coastal People, Communities and Economies at Risk 24 Sustaining economic growth into the future 25 The escalating environmental challenges 26 Conclusion: Urgent Action Now 30 Recommended Reading 32 Authors and Expert Reviewers 33
THE CORAL TRIANGLE
AND CLIMATE CHANGE
About This Report
The Coral Triangle is the world’s centre of marine life, with more species Unfortunately, the relationship of local threats. In this world, the World leaders have a choice.
living in this area than anywhere else on the planet. It sparkles as the between people and coastal biological treasures of the region They have a chance to make
biological treasure chest of our planet, with many of its mysteries and ecosystems is now under extreme are destroyed by rapid increases a difference, to the future of our
species yet to be discovered. threat from climate change, as well in ocean temperature, acidity planet’s biological inheritance and
as escalating local and regional and sea level, while the resilience the lives of millions of vulnerable
Over thousands of years, people have built communities and businesses environmental pressures. Regional of coastal ecosystems deteriorates people living within the Coral
around this remarkable biological wealth. Today the region supports multi- and international action is urgently under ineffective coastal management. Triangle, or not. By making tough
billion dollar tuna, fishing and tourism industries, and over 100 million people needed to avoid an ecological and Poverty increases, food security decisions today, they can take
rely directly on its coastal resources for their food and livelihoods. human catastrophe. plummets, economies suffer and us towards that better world,
coastal people migrate increasingly one in which the threat of climate
This report sets out the full extent to urban centres. change has been reduced, and human
of the threats and proposes solutions communities and coastal resources
to the challenges facing the Coral In the other world, effective action can exist in harmony.
Triangle and its people. Based on a is taken by world leaders to curb the
thorough consideration of the climate, build up of greenhouse gases, leading Professor Ove Hoegh-Guldberg
biology, economics and social to the stabilisation of concentrations University of Queensland
characteristics of the region, it shows of atmospheric CO2 at the lower James P. Leape
why these challenges are increasing, end of IPCC projections in the latter Director General WWF International
and how unchecked climate change half of this century. Climate change
will ultimately undermine and destroy is challenging but manageable, and
ecosystems and livelihoods in the the Coral Triangle region decisively “...it shows why
Coral Triangle. reduces other environmental stresses
arising from overfishing, pollution, these challenges are
The report offers two possible declining coastal water quality and increasing, and how
scenarios for the future. In one world, health. In this world, because the
the international community continues impacts are less and growth strategies unchecked climate
down a track towards catastrophic are more focused on people than change will ultimately
climate change and the Coral Triangle profits, communities and economies
countries do little to protect coastal continue to grow sustainably into undermine and
ecosystems from the onslaught the future. destroy ecosystems
and livelihoods in the
Coral Triangle.”
2: THE CORAL TRIANGLE
3
THE CORAL TRIANGLE
AND CLIMATE CHANGE
Executive Summary
The Coral Triangle stretches across Unfortunately, the coastal ecosystems Climate change is also threatening stresses. They are based on extensive face from deteriorating water quality,
six countries in Southeast Asia and of Coral Triangle are deteriorating coastal mangroves within the Coral information about how ecosystems, overexploitation of marine resources,
the Pacific (Indonesia, Philippines, rapidly and 40% of coral reefs and Triangle, which are highly sensitive to people and economies within this destructive fishing, pollution and
Malaysia, Papua New Guinea, mangroves have already been lost rising sea levels. A multitude of other region might fare in these very shipping activity in the region.
Solomon Islands and Timor Leste) over the past 40 years. Coastal changes are destabilising critically different worlds (for full details: Even if the world succeeds in reducing
and is the richest place on earth in deforestation, coastal reclamation, important ecosystems along the coasts. www.panda.org/coraltriangle). emissions, and slowing down or halting
terms of biodiversity. In no more than declining water quality, pollution, Stresses arising from climate change climate change impacts, enough change
1% of the Earth’s surface, evolution sewage, destructive fishing and over- are also amplifying the impacts of Consideration of these two scenarios is already occurring to indicate that
has produced species and ecosystems exploitation of marine life have had local stresses, leading to an accelerated leads to the irrefutable conclusion that action on global climate change without
that are unrivalled in number, colour a severe impact on these essential deterioration of coastal ecosystems. stabilising atmospheric carbon dioxide dealing with these serious local issues
and diversity. Within its seas, ecosystems. This is placing many (CO2) at or below 450 parts per million will be ineffective, and vice versa.
lie the richest marine communities communities and businesses within While coastal ecosystems are facing (ppm) is absolutely essential if Coral
and ecosystems found anywhere on the Coral Triangle at risk. enormous pressures from both local Triangle countries are to meet their This report delivers a sombre warning
planet Earth. With over 30% of the and global factors, many areas within objective of retaining coastal ecosystems that decisive action must be taken
world’s coral reefs, including 76% Climate change is now joining the the Coral Triangle show significant and allowing people to prosper in the immediately or a major crisis will
of the world’s reef building corals stresses that are affecting Coral Triangle ecological resilience and are therefore coastal areas of the Coral Triangle. develop within the Coral Triangle
and over 35% of the world’s coral ecosystems and people. Changing among the most likely to survive the The second major conclusion is that over the coming decades. There are
reef fish species, the Coral Triangle weather patterns are causing floods, challenging times ahead. High levels changes to Coral Triangle ecosystems a number of actions, which, if taken
is remarkable and invaluable. landslides and severe storms in some of biodiversity, coupled with fast rates are inevitable due to the lag effects of up by regional and world leaders,
areas, and crippling drought in others. of growth and recovery, put many climate change and ocean acidification will help Coral Triangle countries
This wonderful cauldron of evolution Rising sea levels are putting pressure Coral Triangle ecosystems in a on coastal and marine systems and avoid this crisis. The policy steps
should be protected in its own right. on coastal communities through storm favourable position to survive climate associated terrestrial habitats. recommended by this report include:
Its value, however, is much greater. surges and inundation of fresh water change. Some parts of the Coral
In addition to the unique biological supplies. Under our present trajectory Triangle may have inherently slower To address the threat of these 1. Create a binding
diversity of the Coral Triangle, over of unfettered growth in greenhouse rates of change in sea temperature and profound and negative changes in the international agreement
150 million people from some of the gas emissions, many parts of the Coral acidity, representing a potential refuge productivity of the system, the essential to reduce the rate and
most diverse and rich cultures on our Triangle will be largely unliveable by in an otherwise rapidly changing world. goal must be to maintain ecosystems extent of climate change.
planet live there. These people depend the end of this century. in their most healthy state in order To do this, emissions should peak
on healthy ecosystems such as coral This summary report assembles to maximise ecological resilience to no later than 2020, and global
reefs, mangroves and seagrass beds Climate change is already having a large amount of information on the climate change. Secondly, dependent warming limited to less than 2°C
to provide food, building materials, a big impact on coastal ecosystems climate, biology, economics and social communities will need to adjust to above pre-industrial temperatures
coastal protection, support industries by warming, acidifying and rising dynamics of the Coral Triangle region their practices to take into account (i.e. atmospheric CO2 < 450 ppm) by
such as fishing and tourism, and many seas. Reefs in the Coral Triangle and builds a picture of two possible the inevitable changes that will be 2100. This will require steep global
other benefits. The services that these have experienced severe mass coral future scenarios. These scenarios are occurring in coastal areas. Therefore, cuts in emissions that are 80% below
ecosystems provide support over bleaching and mortality events based around decisive international the region-wide national commitment 1990 levels by 2050. Inherent to this
100 million people who live along the as temperatures have periodically action (or non-action) on climate to address the serious threats to coastal recommendation is the creation
coasts of the Coral Triangle islands. soared. These splendid reef systems change, combined with effective systems is essential. Coordination and of an aggregate group reduction
will disappear if these events continue action (or non-action) on reducing collaboration is necessary to reduce the target for developed countries of 40%
to increase in intensity and frequency. the impacts of local environmental stresses that coastal resources currently below 1990 levels by 2020, and a
4: THE CORAL TRIANGLE
5
reduction from business-as-usual actions not aim to restore or protect spending funds and taking actions adaptation strategies which may development planners so that they
emission levels for developing ecosystems for past conditions, rather that exacerbate the problem prove most successful. Reducing can immediately implement these
countries of at least 30% by 2020. they must prepare for conditions under of climate change. the influence of local stress factors new approaches. As the problem of
a changing climate. on coastal ecosystems makes them climate change is not one that we will
2. Take immediate action 6. Establish governance able to better survive climate change be solving in this generation, planning
to establish national 4. Support the structures that impacts. Protecting the diversity and responses to climate change will
targets and plans to meet establishment of integrate resource of components (communities, be iterative as the target continues
these commitments such a global fund to meet and development populations, and species) under the to move over the coming centuries.
that the international the adaptation needs management to provide guidance and actions of local people Therefore, it will also be necessary to
agreement can be of developing countries. robust protection strengthens the resolve of these develop training for future capacity
achieved. While some of the cost of adapting of both in the face systems in the face of climate change. through education in academic or
This report shows that nations in to climate change can be met by of climate change. other appropriate settings. Informed
the Coral Triangle region have a redirecting current resources that Adaptation plans cannot be developed 8. Critically review and stakeholder and community
great deal at stake if climate change are being used in a manner that is on a sector-by-sector basis. Doing revise conservation and engagement is at the core of
continues unchecked. They must vulnerable to climate change, the so risks creating problems such as development efforts at successful adaptation, so in addition
become part of the solution. They growing challenge of climate change adaptation being effective against the local, national and to professionals and students, civil
must do this expeditiously. Lag- will result in new and increasing one issue but maladaptive against regional levels for their society must be given access to the
times and non-linear responses in the costs. Funds will be required to meet another. It will be important to plan robustness in the face information they need to understand
climate system mean that every day these costs given the nature of the holistically and create governance of climate change. and respond to climate change.
we wait to take action, the problem problem and that the disproportionate structures that can support, implement Business-as-usual conservation and
becomes protracted and dramatically brunt of the hardship caused by the and monitor these efforts. development will not achieve success. 10. Focus adaptation
more difficult to address successfully. problem is borne by developing The new mode of action requires on playing a role in
countries. International funds will 7. Build the socio- integration between conservation economic stimulus,
3. Pursue the be necessary to meet these needs. ecological resilience and development, and the realisation especially in job
establishment of of coastal ecosystems that many past approaches are no creation and financial
integrated coastal 5. Build adjustable and develop stakeholder longer effective due to the impacts mobilisation.
zone management financial mechanisms into and community of climate change. Private-public sector incentive
across the region. national budgeting to engagement processes for schemes, regional/international
This step is essential if the current help cover the increasing communities to improve 9. Build capacity to arrangements and investment
decline in the health of coastal costs of adaptation to their ability to survive engage in planning partnerships (e.g. national insurance
ecosystems is to be reversed. This climate change. climate change impacts. for climate change. reform and special-access loan
should include implementation of Climate change will require not only Involving coastal people and Climate change planning, both schemes) need to better incorporate
policies that eliminate deforestation new funds, but also a reassessment of communities in planning provides mitigation and adaptation, will risk management and adaptation
of coastal areas and river catchments, current spending so that funds are not greater stability and efficacy for require that we educate current and strategies to reduce investment
reduce pollution, expand marine spent in ways that are not ‘climate- solutions to social and ecological future leaders and practitioners, as risk and maintain positive
protected areas, regulate fishing smart’, in other words, on efforts that systems within the Coral Triangle. well as the concerned constituencies. financial conditions.
pressures and abolish destructive are not resilient to climate change. Fundamentally, it will be local Mechanisms must be created to
practices. It is important that these Every effort should be made to avoid knowledge that generates innovative train current resource managers and
THE CORAL TRIANGLE
AND CLIMATE CHANGE
The Imperative:
Which Future Will We Choose?
The central objective of this study was to explore how the future will unfold BEST OR WORST CASE SCENARIO? examined in this report. The first The three A1 options are
if we do or do not take action on climate change and other serious threats At the outset, it is sobering to note world takes only moderate steps to distinguished by their technological
to coastal ecosystems in the Coral Triangle. To do this, scenarios were that the pathway that the world is deal with climate change, continues emphasis: fossil-intensive (A1FI),
constructed from comprehensive information on environmental, biological, on today exceeds the worst-case to globalise and is driven by purely non-fossil energy sources (A1T),
economic and social drivers within the Coral Triangle, based on updated global scenario described in this report. economic imperatives (A1 scenario or a balance across all sources (A1B).
scenarios originally established by the Intergovernmental Panel on Climate At current growth rates of CO2 - here termed “worst case”). In the
Change (2001). The latter were modified to include new and compelling emissions (>2 ppm year-1), we are second world, strong action is taken Given that the A1FI scenario is
science published since the release of the IPCC’s Fourth Assessment Report currently travelling along a trajectory on climate change, and robust regional considered too dangerous a future for
in 2007. These scenarios form credible pictures of the future, which served to which exceeds even the disastrous A1 and international commitments exist the planet by most experts, the report
illustrate the outcome of particular decisions that we make today. The data sets Fuel Intensive (A1FI) scenario of the that ensure environmental concerns assumes that the world will move
and the complete description of these scenarios are included on the website for IPCC. Given the growing evidence and human welfare are tightly steadily away from fossil fuels and
this report (www.panda.org/coraltriangle). of runaway climate change, feedback integrated with economic goals and develop technological capacity to use
amplification and other dangerous objectives (B1 scenario – here termed a range of economically viable energy
Figure 1. Schematic representation of the four major SRES scenarios (source IPCC 2001). “surprises” (e.g. sudden breakdown “best case”). solutions, including both renewable
Different worlds represent different combinations of global/regional and economic/environmental drivers,
of polar ice), following this pathway sources and systems designed to
and arise from a range of driving forces (represented as roots to the tree). A1 and B1 are global scenarios
that are dominated to different extents by economic (A1) versus environmental (B1) motivations. It is would result in rapid global change WORST CASE (A1B) make fossil fuel use environmentally
important to note that economic and environmental goals may not necessarily oppose each other and with ensuing social, political and SCENARIO: FAILURE TO safe (such as carbon sequestration).
certainly synergise in many circumstances (e.g. Triple Bottom Line).
economic changes that are likely REDUCE CLIMATE CHANGE This is the A1B scenario, which
SRES Scenarios to be devastating and unmanageable AMID ESCALATING LOCAL involves economic-growth orientated
(and hence, not predictable to any THREATS balanced-energy use. Given the
degree of certainty from 2060 or The A1 scenario describes a future serious challenges presented by the
Economic thereabouts). Needless to say, this world typified by very rapid economic A1B world in which atmospheric
scenario must be avoided at all costs. growth, a global population that peaks CO2 exceeds 750 ppm and global
A1 A2 There is no longer any doubt that we in mid-century and declines thereafter, temperature rises more than likely to
must make dramatic changes to our and the rapid introduction of new and exceed 3°C, this was adopted as the
Global Regional energy use to reduce our greenhouse more efficient technologies. Major worst-case scenario of this study.
B1 B2 gas emissions. underlying themes are convergence
among regions, capacity building, The full report discusses the complete
The Special Report on Emissions and increased cultural and social set of demographic, social and
Scenarios (SRES) of the IPCC defines interactions, with a substantial economic trends associated with
Environmental
four basic scenarios (see FIGURE 1) reduction in regional differences in the A1B scenario. In this scenario,
Agr based on their degree of economic per capita income. The A1 scenario demographic and economic trends
i
on (Lan c are closely linked, as affluence is
Economy
ti versus environmental motivation, has three options that describe
Popula
ult
d correlated with long life and small
y
and global versus regional focus. alternative directions of technological
Ene
g
u re
rg
lo
o
-us
hn y
Tec Two possible future worlds are change in the energy system.
e)
Driving Forces
6: THE
THECORAL
CORALTRIANGLE
TRIANGLE7
families (low mortality and low IMPLICATIONS OF The rapidly changing climate required by thousands of organisms, Foreign aid to alleviate these food
fertility). Global population grows to THE A1B SCENARIO FOR associated with the A1B scenario including important fisheries species. shortages dwindles as richer nations
some 9 billion by 2050 and declines THE CORAL TRIANGLE leads to major impacts on the The result of these changes is face their own escalating problems
to about 7 billion by 2100. The A basic outcome of the A1B scenario Coral Triangle through changing that coastal fisheries are severely and costs from climate change, and
average age of citizens increases, is that poorer countries and their precipitation and soaring degraded by 2100. The ability of reef as the regularity and scale of these
with the needs of retired people met people bear the negative impacts temperatures by 2050. The systems to provide food for coastal disasters expands. Tens of millions
mainly through their accumulated of climate change. Within the Coral Philippines, Sabah and parts of populations decreases 50% by 2050, of people in the Coral Triangle
savings in private pension systems. Triangle, this places the Solomon Indonesia (Sumatra, Java and and 80% by 2100 (compared to their region have to move from rural and
Islands, Papua New Guinea and West Papua) are hit hard by ability to provide food today). coastal settings due to the loss of
The A1B scenario sees concentrations Timor-Leste in the most vulnerable increasingly intense rainfall events homes, food resources and income,
of 710 ppm CO2 by 2100, through category, especially as these which are alternated with long, severe putting pressure on regional cities
a path taking it from 360 ppm in countries will experience serious droughts (in some areas), and in the and surrounding developed nations
2000 to about 410 ppm in 2020, impacts as global temperatures case of the Philippines, catastrophic such as Australia and New Zealand.
430 ppm in 2040, 550 in 2060, rise beyond 30C. All Coral Triangle typhoons. Rising seas steadily
and 630 in 2080. All areas of the countries are considered to be inundate coastal communities across
Coral Triangle will have carbonate developing countries, although Indonesia, further exacerbating the Figure 2. Hypothetical trajectory of the concentration of atmospheric CO2 and coral cover in a A1B world.
ion concentrations (critical for Malaysia, with Indonesia and impacts of the increases in rainfall Stabilisation at 750 ppm
marine calcification) by 2050 that the Philippines following and storm activity. These trends cause
are less than 200 µmol kg-1 H2O closely, may be on their way to increasing dislocation of people and 800 100
(i.e. the concentration required to newly industrialised status. This communities through flooding and ic CO 2
Atmospher
Atmospheric carbon dioxide (ppm)
750
Coral cover relative to today (%)
maintain carbonate coral reefs). development may accelerate during storm damage, with growing scale
The best-estimate of the increase and frequency as the century unfolds.
W
the first two or three decades of this 700
ea
in global temperature (nb: tropical
km
century in a strong global economic
an
sea temperatures mirror global growth scenario, before the full Coastal ecosystems are impacted 650
a
ge
temperatures) will be more or less impact of climate change begins to heavily from warming seas which
me
600
2.8°C above today by 2100, with a cause increased coral bleaching
nt
have major impacts on the economy 50
very high chance that it will exceed of these countries. Within the Coral and mortality (Figure 2). Rapidly 550
3 or even 4°C. While sea levels are Triangle, however, Sabah and increasing sea levels remove
projected by the IPCC (2007) to Eastern Indonesia are significantly mangroves and inundate coastal 500
increase by an average of 28 cm poorer than the rest of the countries groundwater supplies. These changes
450
by the end of century, most recent to which they belong, so national result in the progressive loss of most
Strong
estimates suggest that the minimum trends in development may not mangroves and coral reefs over 400 manag
ement
sea level rise is more likely to one apply as strongly to areas of these the next 50 years. These changes
metre by 2100. degrade habitats that are 350 0
countries associated with the
1950 2000 2050 2100 2150 2200 2250 2300 2350
Coral Triangle.
YearTHE CORAL TRIANGLE
AND CLIMATE CHANGE
Key Characteristics
of the Worst-case Scenario
The key features of the worst-case (A1B) scenario for the Coral Triangle INCREASING VULNERABILITY provide 50% of the fish protein that conditions within crowded urban
are summarised below. OF COASTAL COMMUNITIES they do today, leading to increasing environments, traditional, family and
Rapidly rising sea levels will lead to pressure on coastal agriculture and cultural integrity are lost. Commercial
DOWNWARD SPIRAL IN COASTAL ECOSYSTEM HEALTH AND BIODIVERSITY the steady loss of coastal land and aquaculture. Access to water for fisheries are likely to put further
Given that atmospheric CO2 will exceed 700 ppm under the A1B scenario, the inundation of coastal freshwater coastal agriculture, however, is likely pressure on regional communities
the health of coastal ecosystems such as coral reefs will steadily decrease supplies. Together with increasing to decrease sharply due to saltwater and their coastal resources. Fishery
to a very low level by the end of the century. There will be few coral reefs, storm intensity, some parts of the inundation of coastal groundwater resources skyrocket in price with
mangroves and seagrass beds that survive given the high sea temperatures, Coral Triangle will experience reduced as sea levels rise, while aquaculture increased demand, as do the activities
low pH, suboptimal carbonate ion concentrations, and rapidly rising sea levels. protection from ocean waves, leading is likely to suffer from the impact of of illegal and unreported fisheries.
Strong management efforts to reduce local threat factors will have minimal to an increasing frequency and scale reduced water quality caused by the
of damage to coastal communities loss of mangrove systems and other DETERIORATING
affect on the decline, and there will be little chance of these ecosystems
REGIONAL SECURITY
recovering for hundreds of years. The loss of these important habitats will and infrastructure. The extent of these coastal ecosystems. The reduced
see approximately 40-50% of marine species decrease to very low abundance, changes will depend on the rate of availability of food in addition to While understanding and projecting
and many will be driven to extinction. sea level rise although even the most the deterioration of water supplies how regional security will change
optimistic projections of sea level is likely to cause increased health is a complex task, reduced food and
change under the A1B scenario will problems and rising infant mortality. water security and the resulting
cause major disruption to coastal National and international aid social disruption represents a
communities. Increases in sea level resources may reduce as a result potent threat to regional security.
of one metre or more will put tens of these wide-scale problems. Radicalisation of some sectors of
of millions of people and their the community may follow,
communities under extreme pressure. SOCIAL DISRUPTION increasing tensions and civil unrest
Many millions will have to move from The movement of people from within the Coral Triangle region.
coastal areas under these scenarios, communities in search of food and
income will lead to the breakdown
with serious consequences for inland
agriculture and other land use. of traditional societies, and increase
“By 2050, coastal
social disruption. The pressure on ecosystems will
REDUCED FOOD SECURITY coastal infrastructure from sea level
The decreased productivity of rise together with reduced food only be able to
availability is likely to cause social
coastal ecosystems will reduce
the food resources and income disruption on large scales. Traditional
provide 50% of
available to coastal communities in fishing communities increasingly the fish protein
the Coral Triangle. By 2050, coastal migrate to cities and towns. As a
ecosystems will only be able to result of the increasingly desperate that they do today.”
8: THE CORAL TRIANGLE9
Table 1: IPCC scenarios: likelihood that each will stabilise at particular increases in CO2 concentrations
Temperature change (0C) CO2 ppm Likelihood that temperature change will be in range
Scenario abundance (crude measure based on IPCC 2007)
Best estimate Likely range in 2100 1-1.99 C
0
2-2.990C 3-3.990C 4-4.990C 50C+
B1 1.8 1.1 - 2.9 545 50% 50%
A1T 2.4 1.7 - 3.8 578 14% 48% 38%
B2 2.4 1.7 - 3.8 616 14% 48% 38%
A1B 2.8 1.7 - 4.4 710 11% 37% 37% 15%
A2 3.4 2.0 - 5.4 846 29% 29% 29% 12%
A1FI 4.0 2.4 - 6.4 964 15% 25% 25% 35%
Source: Based on IPCC 2007 Synthesis Report, Table 3.1.
Notes:
1. These estimates are from various sources including a large number of Atmosphere-Ocean General Circulation Models
(AOGCMs). They do not take account any deterioration of climate change prospects after IPCC 2007 was finalized.
The estimates are therefore conservative.
2. Temperature changes are expressed as the increase from 1980-1999 to 2090-99. To express the change relative to the
period 1850-1899 add 0.50C.
3. The three A1 scenarios are A1T (non-fossil energy resources), A1FI (fossil-intensive), and A1B (balance across all energy
resources). A1 and A2 are driven by economics (mostly short-term gains), globally and regionalized, respectively. B1 and
B2 put more emphasis on protecting environmental resources, again either in a global context or in a world with many
regions working independently.THE CORAL TRIANGLE
AND CLIMATE CHANGE
Best Case (B1) Scenario:
Decisive international action on climate change while
building sustainable coastlines and communities
The central elements of the B1 scenario family are a high level of environmental basis of poverty. However, counter- The target of 545 ppm CO2 in 2100 is with determination (requiring the
and social consciousness combined with a globally coherent approach to more currents may develop and in some likely to become rapidly unacceptable world to decisively leave the current
sustainable development. In this storyline, governments, businesses, the media, places people may not conform to according to the latest science (detailed business–as-usual pathway).
and the public pay increased attention to the environmental and social aspects the main social and environmental in the full report), as is the path Under this scenario, temperatures
of development. Globally, appreciation of the importance of triple bottom line intentions of the mainstream. The towards that target: 405 ppm in 2020, increase an additional 2.20C by 2100.
solutions that balance economic, ecological and social needs grows. As in the income redistribution and high taxation 425 in 2040, 490 in 2060, and 535 ppm The reduction in emissions to 90%
A1B world, technological change plays an important role. levels required may adversely affect the in 2080. This puts increasing pressures of today’s level by 2050 has a small
economic efficiency and functioning on policies to drastically reduce but significant impact on the rate
Economic development in B1, however, is balanced, and efforts to achieve of world markets. emissions, possibly starting from 2015. of temperature change relative to the
a more equitable distribution of income are effective. As in A1, the B1 storyline A1B trajectory, with this difference
describes a fast-changing and convergent world, but their priorities differ. Referring to Table 1, the best-estimate The challenge of staying within increasing to become very significant
Whereas the A1 world invests its gains from increased productivity and know- stabilisation level for scenario B1 sustainable levels of atmospheric by the end of the century.
how primarily in further economic growth, the B1 world invests a large part of is 1.8oC above today’s temperature, greenhouse gases (below 450 ppm)
its gains in improved efficiency of resource use, equity, social institutions and with a 50% risk that global temperature remains a formidable one. In the best As the concentration of CO2increases
environmental protection. A strong welfare net prevents social exclusion on the might stabilise between 2 and 3oC. case world, these challenges are met in the atmosphere, Coral Triangle
“Effective management of coastal
resources through a range of options
including locally-managed regional
networks of marine protected areas,
protection of mangrove and seagrass
beds and effective management
of fisheries results in a slower decline
in these resources.”
10: THE CORAL TRIANGLE11
waters experience carbonate ion communities are able to absorb still significant relative to today). expansion of these ecosystems in the the latter part of this century, greater
concentrations that approach but stay greater challenges and hardships Disturbances to rainfall patterns early part of next century. Effective amounts of development aid at both
slightly above the critical value (some of which we cannot hope cause serious problems in parts of management national and international levels help
of 200 µmol kg-1 H2O by 2060 to predict) through greater economic, the Coral Triangle, and typhoons in of coastal resources through a range coastal communities cope with the
due to continuing proactive efforts social and cultural resilience. the Philippines increase in intensity. of options including locally-managed changes that they face. While there
for deep cuts in the use of fossil fuels. Investment in infrastructure Moderately severe droughts push some regional networks of marine protected are movements of people increasingly
Like the A1B scenario, sea level rise and resource management at communities into periodic hardship. areas, protection of mangrove towards urban centres as coastal
is projected to increase around the village and township level While these conditions cause some and seagrass beds and effective ecosystems decline, the reduced
25-35 cm by the end of century (IPCC lead to greater supply of natural dislocation of people and communities management of fisheries results in rate of climate change enables other
2007) but most recent estimates and social capital with which to through flooding, sea level rise and a slower decline in these resources. resources such as agriculture and
aquaculture to fill important gaps
foresee the minimum sea level rise in respond to the challenges. storm damage, the scale and frequency
in food supply.
the vicinity of 50 cm by 2050. of the impacts decrease dramatically Due to the B1 world being a richer
In this world, atmospheric CO2 toward the latter part of the century. and more connected world towards
IMPLICATIONS OF content begins to stabilise around the
THE B1 SCENARIO FOR middle to late part of the century. Warming and acidifying seas kill Figure 3. Hypothetical trajectory of the concentration of atmospheric CO2 and coral cover in a B1 world.
THE CORAL TRIANGLE It continues to find solutions to coral and decrease reef calcification
The impacts of a changing climate continue reducing CO2 emissions as atmospheric CO2 approaches 450
have large effects on coastal areas through strict international control. ppm. Carbonate ion concentrations
480 100
of the Coral Triangle and the Sufficient food resources remain are low but remain above the 200
Atmospheric carbon dioxide (ppm)
availability of protein from fisheries available to enable Coral Triangle μmol.kg-1 H2O, leading to reduced
Atmospheric CO2
Coral cover relative to today (%)
460
is reduced to half of present levels. communities to survive despite coral growth as well as cover (but
Sea levels increase by 50 cm by 2050, decreases in the productivity of not as low as in A1B, c.f. Figure 2 440 ement
as in the worse-case scenario. While coastal fisheries. Areas with low with Figure 3). Increasing sea level manag
Strong
this may look pessimistically like the food supplies, including those in plus rising storm intensity lead to 420
worst-case (A1B) world, there are the three largest Coral Triangle reductions in the overall extent and
some important differences. countries (Indonesia, Philippines and condition of mangrove and seagrass 400 50
Malaysia) have been supported in beds, with consequences for habitats ent
One of the characteristics of the this interconnected and significantly and species abundance across the 380 Weak managem
B1 scenario is that communities richer world. coastal zone. As in the A1B scenario,
360
remain reasonably intact, and hence warming and acidifying seas drive
are in a better position to cope with While the B1 world is certainly not a steady deterioration of coastal
340
fairly severe hardships surrounding without its challenges, it experiences ecosystems, with the difference
the gradual 50 cm sea level rise by environmental challenges that are that effective management leads to 320 0
2050 on coastal fishing, agricultural relatively smaller than those seen in a delay in their decline (green line 1950 2000 2050 2100 2150 2200 2250 2300 2350
and urban communities. More intact the A1B the world (but which are in B1 figure), then recovery and
YearTHE CORAL TRIANGLE
AND CLIMATE CHANGE
Key Characteristics
of the Best-case Scenario
The key features of the best-case Until atmospheric CO2 stabilises, stress factors and to protect important As with the worst-case scenario, more confident about meeting the
(B1) scenario for the Coral Triangle coastal ecosystems will continue habitats and refugia have a large rising sea levels lead to the steady loss challenges. Significant numbers of
are summarised below. to face stress from rising sea positive influence on the abundance of land and the inundation of coastal people will still have to be absorbed
temperatures, reduced carbonate and health of coastal ecosystems. water supplies, and the risk of damage into urban areas as their communities
REDUCED BUT EVENTUALLY concentrations and rising sea levels. from storms increases with storm are inundated, but the numbers of
REBOUNDING COASTAL CHALLENGED BUT RESILIENT
The abundance of healthy corals, intensity and higher sea levels. people moving will be far less than
ECOSYSTEM HEALTH AND COASTAL COMMUNITIES
BIODIVERSITY mangrove and seagrass communities These challenges start to increase that seen in the A1B scenario.
will decline but will eventually rebound Coastal communities will still face steadily over the next couple of
The atmospheric CO2 concentrations significant challenges despite the STABILISED FOOD SECURITY
as atmospheric CO2 stabilises. Under decades but will start to decrease
stabilise at or just below 450 ppm implementation of effective measures
this scenario, strong management around 2050. Coastal communities As in the A1B scenario, the
under the modified B1 scenario. to stabilise atmospheric CO2.
efforts to reduce the impacts of local have more resources and are productivity of coastal ecosystems
will decrease, with the result that
there is 50% less protein from coastal
resources by 2050. The difference,
however, is that alternative resource
options exist through agriculture
and aquaculture, which occur
within a B1 landscape that is more
environmentally aware than the A1B.
Finding alternative water resources
may represent important challenges to
coastal communities for the first part of
the century as saltwater driven by rapid
sealevel rise inundates groundwater.
The more intact mangrove systems,
having been protected and managed,
will help maintain water quality along
coastlines which adds to the resilience
of coastal ecosystems, slowing their
decline until they start to recover at the
end of the century. Local communities
collaborate with regional bodies on
integrated coastal management,
12: THE CORAL TRIANGLE13
with many traditional societies and regulation of local fisheries. EPILOGUE TO SCENARIOS
playing direct and important roles. Commercial fishing is regulated Predicting the precise nature of
Coastal ecosystems like coral reefs by a regional set of agreements future worlds is inherently difficult
benefit from integrated marine among Coral Triangle nations, given the vast number of unknowns,
protected areas, and provide leading to a stabilisation of fish and their interactions and synergies.
sustainable resources. Carefully stock numbers and availability. Establishing scenarios from the
constructed regional policies on analysis of likely drivers illustrates
fishing preserve and strengthen STRENGTHENED
REGIONAL SECURITY different potential futures based on
regional economic benefits. Although decisions taken today. In the two
food and water security are reduced, The reduced levels of poverty
scenarios examined in this report, the
communities suffer less from health as well as the preservation of
two worlds stand in stark contrast
issues and infant mortality is lower, strong community ties lead to
to each other, depending very much
and receive greater support from reduced mobility of people and the
on which steps we take today to
national and international aid sources. resulting social disruption. There is
influence the rate of climate change,
correspondingly less marginalisation
and to deal with the other serious
REDUCED SOCIAL CHALLENGES of sectors of society within the
threats that face coastal ecosystems
The movement of people out of their region. Within a world that is more
across the Coral Triangle.
communities in search of food and connected and environmentally
income has been reduced, resulting sensitive, these trends mean that
There is no credible argument to
in a lower level of social disruption. regional security is significantly
say that the unique biodiversity and
People are in a much better situation strengthened. Partnerships like
economies of the Coral Triangle
under this scenario compared to the the Coral Triangle Initiative form
will be safe if we continue to pump
A1B scenario, especially towards the important mechanisms by which
carbon dioxide into the atmosphere.
later part of the century. This more issues are resolved peacefully across
Equally, there is no credible argument
collaborative and integrated world the region, with benefits for all
to say that ignoring the threats
leads to a strengthening of social partners, and are extended to other
that these ecosystems face from
bonds between people and their challenges facing CT6 nations.
escalating overfishing, pollution
coastal resources, maintaining social The common set of goals for the
and deteriorating water quality will
resilience and traditional values and Coral Triangle serves as a uniting
ensure their future. Knowing this, it
beliefs. The latter is used to support purpose for the region, with benefits
is imperative that we take immediate
local, community-based management to a wider sphere of national and
and decisive action to deal with both
of marine protected areas, regional objectives.
these serious threats.THE CORAL TRIANGLE
AND CLIMATE CHANGE
The Global Challenge:
Climate Change
Climate change is one of the defining issues of our time, and is set to radically LONGER AND MORE INTENSE
transform the world we live in. It has been driven by rapid increases in FLOODS AND DROUGHTS
atmospheric greenhouse gases (primarily CO2) arising from the burning of There are some indications that
fossil fuels by industrialised countries. Atmospheric concentrations of CO2 are equatorial Pacific rainfall, especially
now 37% higher than they have been at any time in the past 650,000 years, and in the vicinity of the ITCZ (Inter-
probably the last 20 million years. These changes have resulted in a dramatic tropical Convergence Zone), will
warming of the planet, which is 0.7°C above pre-industrial temperatures, and increase although there are conflicting
is currently increasing at the rate of 0.12°C per decade. Rates of change are scenarios provided by different
also several orders of magnitude higher than anything seen in the last million climate models. Even without changes
years. The impacts have already been dramatic. The loss of over 70% of the in average rainfall, it seems likely
summer ice that has been stable in the Arctic Ocean for many thousands of years that rainfall events will become more
emphasies the seriousness of the situation for the environment and for humanity. extreme and the annual variability of
monsoon rainfall will increase. There
IMPACTS HAVE ALREADY BEGUN is evidence that this key change has
Predicting how local environments will change in a rapidly warming world already begun to occur. Importantly,
ACIDIC SEAS WILL DRIVE Triangle within the period 2020-2050
is challenging, especially for a region like the Coral Triangle. Ultimately, REEF COLLAPSE the intensity of drought will be greater
(Figure 6), with the real possibility
the accuracy of any projection depends on how atmospheric CO2 continues in a warmer world, severely affecting
Ocean acidification has already driven that many coral reefs will begin to
to change, aspects of climate inertia, and the degree to which models can large parts of the Philippines and other
pH downward by approximately crumble and disappear as corals fail
be downscaled to the regional level. Nonetheless, there are general trends areas of the Coral Triangle (Figure 7).
0.1 pH units due to absorption by to maintain the calcium carbonate
emerging in the climate of the Coral Triangle region which allow us to project the surface oceans of approximately structures that underpin them. This
SEA LEVELS RISING 0.5, 1.0
with some certainty how conditions will change over the next 50 to 100 years. 30% of the extra CO2 injected into will have huge consequences for OR 6.0 METRES?
It should be stressed that these projections are likely to be conservative, with the atmosphere from the burning the tens of thousands of species
many leading scientists now concluding that we are likely to see the upper Sea level has already increased
of fossil fuels and other human dependent on coral reefs. On longer
extremes of these projections eventuate. and projections from the Fourth
activities. This is driving carbonate timescales, protection of coastal cities
Assessment Report of the IPCC
ion concentrations downward, thereby and infrastructure from ocean waves
CORAL TRIANGLE SEAS WILL BE WARMER BY 1-4OC suggest that seas will rise by 30 to
reducing the ability of corals and by coral reefs may disappear, which
The annual, maximum and minimum temperatures of the oceans surrounding 60cm by 2100. Further research
other marine calcifiers to build their could be catastrophic for millions of
the coastal areas of the Coral Triangle are warming significantly (0.09 – 0.12oC since the IPCC’s Fourth Assessment
skeletons. Available evidence suggests people, especially when combined
per decade, Figure 4, Table 2) and are projected to increase by 1-4°C toward Report (June 2007, Table 3) suggests
that these conditions will become with rapid sea level rise and more
the end of this century (Figure 5). This will put pressure on coral reefs through that these projections may have
“marginal” for coral reefs of the Coral intense storms.
increased bleaching, disease and mortality. Increases of more than 2°C will underestimated sea levels by a
eliminate most coral dominated reef systems. considerable amount. Most sea
level experts now project that the
14: THE CORAL TRIANGLE15
minimum sea level rise is likely is already occurring. Large parts of In this respect, we know very little
to be one metre by the end of the the Coral Triangle lie outside the about how ocean circulation within
century. Palaeological evidence cyclone/typhoon belts and may be the Coral Triangle will change
reveals that major ice sheets on the unaffected. However, the Philippines under the influence of increasing sea
planet can break down over decades and Solomon Islands, which are temperatures and ocean dynamics.
(much more rapidly than previously affected by typhoons and cyclones, Changes in the circulation of oceans
thought), with huge consequences are likely to experience changes in within the Coral Triangle would
for the sea level. Many scientists their intensity and impact. have significant impacts on the
are now warning that rapid ice sheet climate and biology of the region.
discharges from Antarctica and EL NIÑO-SOUTHERN
OSCILLATION EVENTS
Greenland are almost inevitable,
leading to the prospect of sea levels These large-scale perturbations Figure 4: Rapid changes in the sea surface temperature are already
to the global climate have a major occurring in the Coral Triangle. Changes across the coral triangle over the
increasing by as much as four to six period 1985-2006. Note the very high rates of increase in sea temperature
metres over the next several hundred influence on sea temperature and in the northern parts of the Coral Triangle. This suggests that within a very
rainfall within the Coral Triangle. short period of time, temperatures may exceed those that corals can tolerate.
years. These higher levels of change (Peñaflor et al., Coral Reefs in press; with kind permission of Springer
represent a major unknown in There is no clear consensus as to Science and Business Media).
the future of all coastal societies; how the frequency and intensity of
the impacts shown in this report El Niño and Southern Oscillation
indicate potentially catastrophic events will change in a warming world
consequences for the Coral Triangle although there is growing evidence
and its people. that the Pacific is likely to become
more “El Niño like”. This phenomenon
MORE INTENSE CYCLONES is likely to continue as a significant
AND TYPHOONS source of annual climate variability in
There is no clear consensus amongst the Coral Triangle region.
global climate models as to whether
the location or frequency of tropical MANY OTHER PARAMETERS
WILL CHANGE
cyclones/typhoons will change
in a warming world but they all Given the complexity of the types
agree that storms will become more of changes that are occurring, and
intense (greater maximum wind will occur, within the Coral Triangle,
speeds and heavier rainfall). Indeed, many other aspects of the Coral
there is substantial evidence that this Triangle region may change as well.THE CORAL TRIANGLE
AND CLIMATE CHANGE
The Global Challenge:
Climate Change
Table 2: Temperatures are sharply increasing across the Coral Triangle region.
Linear trend, 1950-2008 and temperature difference (1989-2008)-(1950-1969) for three Coral Triangle
Location of 3 CT-SST regions
regions and global land and sea temperatures and tropical ssts (all values significant at 5% level).
o
C per decade
Global Land Tropical sea surface
CT Region 1 CT Region 2 CT Region 3
& Sea Temperature
Trend 0.12 0.08 0.12 0.09 0.11
Difference ( C) o
0.45 0.29 0.49 0.37 0.44 1
3
Table 3: Projected global temperature changes, sea-level rise (relative to 1980-99) and co2
concentrations for various sres scenarios (Bindoff et al., 2007; Meehl et al., 2007). The last column lists
2
the expected outcome under each scenario.
Scenario Temperature Sea level rise CO2 Outcome for coral reefs
B1 (modified) +1.8 (1.1-2.9) oC 0.18-0.38 m 450 ppm Decrease of coral communities to 10-30% of today’s
abundance; reef structures struggle to maintain
themselves. Reducing the impact of local stressors
becomes extremely important under this scenario.
A2 +3.4 (2.0-5.4) oC 0.23-0.51 m 750-800 Complete collapse of coral communities due to
ppm mass coral bleaching and mortality, and conditions
which will slow and reverse coral reef accretion and
maintenance.
A1FI +4.0 (2.4-6.4) oC 0.26-0.59 m 950-1000 Complete collapse of coral communities. Must be
ppm avoided at all costs.
16: THE CORAL TRIANGLE17
Sea temperatures will increase Ocean acidity will rise Rainfall patterns are likely to change
Figure 5: Trends in ocean temperature will continue and will intensify Figure 6. Reef calcification will decrease to very low levels if atmospheric co2 Figure 7: Major changes in precipitation will cause larger flood events and longer droughts.
under both b1 and a2 (and a1b) scenarios. Multi-model annual mean increases above 450 ppm. Projected changes in the aragonite saturation state (i.e. Multi-model seasonal precipitation differences (%) for b1 (top) and a2 (bottom) scenarios during
surface temperature differences (C°) for b1 (top row) and a2 (bottom row) availability of calcium and carbonate ions required for calcification) of sea water as a Dec-Feb versus Jun-Aug for periods 2026-2035 and 2090-2099.
for period 2026-2035 and 2090-2099 (relative to 1980-1999). (Data provided function of atmospheric co2 concentration (white number in each panel, ppm). The pink
by Julie Arblaster based on Meehl et al., 2007). dots represent the current distribution of carbonate coral reef ecosystems. The regions
B1 scenario Dec-Feb
suitable for coral reefs are defined by the blue areas – note that the conditions necessary
for carbonate reef development contract to the equator (and the Coral Triangle) with
2026 - 2035 2090 - 2099
increasing levels of atmospheric carbon dioxide (reprinted with permission from Science
B1 B1 Magazine, Hoegh-Guldberg et al. 2007).
10 N
0
10 S
120E 140E 160E 120E 140E 160E
Jun-Aug
2026 - 2035 2090 - 2099
10 N
A2 A2
0
10 S
120E 140E 160E 120E 140E 160E
A2 scenario Dec-Feb
2026 - 2035 2090 - 2099
10 N
0
10 S
120E 140E 160E 120E 140E 160E
Jun-Aug
2026 - 2035 2090 - 2099
10 N
0
10 S
120E 140E 160E 120E 140E 160ETHE CORAL TRIANGLE
AND CLIMATE CHANGE
Small Changes Have Big Impacts
The coastal ecosystems that define the Coral Triangle are extremely sensitive CORAL REEFS WILL maintain the reefs that they build today. through defoliation. In turn, this will
to changes in the environment around them. While the change in global BEGIN TO DISAPPEAR AS CO2 These changes are not merely academic result in increased wave action and
CONCENTRATIONS APPROACH predictions; recent research has shown serious damage to seagrass beds.
temperature may seem small (e.g. 0.09 – 0.12oC per decade), climate change 450 PPM
is already having a major impact on coastal ecosystems. Warming over that the calcification of corals in places
Small increases in sea temperature like Thailand and Australia’s Great NOT JUST ABOUT CORALS,
the past century has pushed ecosystems such as coral reefs closer to their
of only 1-2oC above today’s summer MANGROVES AND SEAGRASS
environmental limits, with the effect that natural variability Barrier Reef has already slowed by
sea temperatures will cause serious 15% since 1990. Corals, mangroves and seagrass are
(e.g. a warmer than average year) puts these important ecosystems under
coral bleaching, disease and mortality. centrally important organisms which
serious pressure. When combined with environmental stresses such as poor
In 1998, the world lost 16% of its MANGROVES AND SEAGRASS BEDS construct the habitat for hundreds of
water quality, pollution or unsustainable fishing, these changes will eliminate
corals in a single global cycle of mass ARE SEVERELY THREATENED BY thousands of other organisms. In the
functional coral reefs and other ecosystems like mangroves from the coastlines SEALEVEL RISE
coral bleaching, which involved sea case of fish, the elimination of coral
of the Coral Triangle. As has been argued elsewhere in this report, the
temperatures reaching 1-3oC above the Mangroves and seagrass beds are reefs compromises the survival of at
consequences of these changes for coastal communities are extremely serious.
long-term average for a few months. also crucial components of the least 30 to 50% of species that need
Coral reefs across the Coral Triangle coastal ecosystems of the Coral corals and the reefs they build for
have been hit hard by mass coral Triangle. Like coral reefs, mangrove food, shelter and reproduction. Similar
bleaching events which have become and seagrass ecosystems provide relationships exist between many
more frequent and intense since the habitat for thousands of species, and organisms that live in mangroves and
early 1980s. In many cases, particularly ecosystem services that are essential seagrass beds. The loss of these key
where reefs have been well managed, to the functioning of the coastline and organisms would mean enormous
they have recovered. At the same time, to its human inhabitants. Increasing changes to the productivity of coastal
however, ocean acidification is driving sea level represents the greatest threat regions and their ability to support
another set of insidious changes in the to mangroves, especially when the people and societies. To lose them
health of coral reefs. Ocean acidification rate of change exceeds the rate of would be to forego any chance of
occurs when CO2 enters the ocean and change in the surface elevation of sustainable future economic prosperity.
reacts with water, creating a dilute mangrove sediments. These changes
acid. The increasing acidity reduces result in a landward migration of INTERACTIONS BETWEEN GLOBAL
the availability of carbonate ions in mangroves, which occurs if the rate AND LOCAL FACTORS
seawater, which allow corals and of sea level rise remains small and Global and local factors causing
other organisms to make their calcium where suitable land is available for stress on coastal ecosystems do not
carbonate skeletons. Atmospheric this landward migration. Increasingly act independently. For example, coral
concentrations of CO2 that exceed strong storms in many parts of the reefs that have experienced significant
450 ppm slow the calcification of corals Coral Triangle (e.g. Philippines) mortality from global warming
to the point where they will struggle to will increase damage to mangroves will recover many times faster if
18: THE CORAL TRIANGLEYou can also read
