Download Ocean Acidification

Ocean Acidification
Remarks by Harlan Cohen
Advisor on Ocean Governance and International Institutions
IUCN the International Union for Conservation of Nature1
I thank the United Nations Secretariat and the UN Foundation for organizing this event
and the invitation to speak today about ocean acidification. Oceans cover 71 per cent of
the Earth’s surface, provide 95 per cent of the Earth’s biome and are thought to contain
approximately 90 per cent of the Earth’s biomass. Thus, the oceans are critical to the
Earth’s well being. Our oceans are crucial to life on Earth. They make Earth what it is.
It is thought that life itself developed in a water environment and human life has its
antecedents in the oceans. We can trace our cells back to the oceans through the saltiness
of our tears, of our blood. Our blue planet is both fragile and resilient.
It was realized several decades ago that the build-up of greenhouse gases – especially of
carbon dioxide through the burning of fossil fuels – in the atmosphere would likely lead
to warming temperatures. This has now been documented. Most discussion of
greenhouse gas emissions focuses on temperature change. With respect of the marine
environment, many think first of threats from sea level rise (caused by thermal expansion
of water and by the melting of ice in the Arctic, in the Antarctic, on Mt. Kilimanjaro, in
the Himalayas, the Andes, the Alps, the Rockies), of poleward shifts of fish stocks, of
projected changes to circulation patterns of ocean currents (the Humboldt Current, the
Benguela Current, the Gulf Stream).
However, the build-up of carbon dioxide in the atmosphere is having other effects on the
marine environment, effects that for marine species and ecosystems may be even more
sinister than temperature change.
The oceans have absorbed some 25-30% of all carbon dioxide emissions from fossil fuel
consumption since the beginning of the industrial revolution, and each year, the marine
environment absorbs approximately 30% of all carbon dioxide emissions that we put into
the air. Already the pH (measure of acidity/base level) in the oceans has changed from
an average of 8.2 to 8.1. While this shift in number may seem small and insignificant, it
is important to remember that the pH table is logarithmic, thus a 0.1 change reflects a
30% change in acidity. It is a big change. Scientists project that on our current track, the
pH of the world’s oceans will change by an additional 0.3 pH, and the average pH level
of the world’s oceans will reach 7.8 before the end of this century. This represents a
huge shift and will have profound implications for marine life. As marine life represents
some 90% of the Earth’s biomass, this will have profound implications for all life on
Earth, including ours. The oceans have not been so acidic in hundreds of millions of
years.
1
The remarks given herein belong solely to the author and do not necessarily represent the views or
policies of IUCN.
This shift in acidity directly threatens marine life. Calcium carbonate-fixing organisms
are perhaps most directly threatened, as they require an alkaline ocean. These organisms
take calcium and carbonate from ocean waters to build structure. The most well known
of these are coral species that build coral reefs and shellfish that depend on hard shells,
for examples mollusks such as mussels, clams, oysters, snails, but also single cell
organisms such as foraminifera and coccolithophores and others that form a basis of the
marine food chain. Coral reefs are one of the most important and productive marine
habitats, providing complex and integrated habitat for many species at different life
stages, including those that we eat (grouper, pompanos). Coral reefs also protect
coastlines by absorbing wave energy. Foraminifera, coccolithophores and other plankton
form the basis of marine food chains that support large mammals, such as whales, and the
many fisheries on which we depend.
The Royal Society in London on behalf of seventy science academies from around the
world released in June of this year an Inter-Academy Panel on Ocean Acidification
statement2 in which the seventy science academies noted that the acidification of the
world’s oceans, like climate change, is a direct consequence of increasing atmospheric
carbon dioxide concentrations and that rapid and deep reductions in carbon dioxide
emissions are the only solution. The seventy scientific academies noted the critical role
that the world’s oceans play in the global carbon cycle and the rapid and irreversible
changes that are taking place in ocean chemistry as a direct result. The scientific leaders
noted the urgent need to act to reduce other stressors, including overfishing and pollution,
on marine ecosystems in order to increase resilience to ocean acidification.3
As the oceans acidify, coral reefs, already under stress from the effects of bottom fishing,
pollution and warming events that can cause coral bleaching, will suffer. The Global
Marine Species Assessment or GMSA, launched in 2005 as the first global review of the
threat of extinction for marine species, included as a priority taxonomic group
scleractinian, or hard, corals. In an astounding discovery it was found that over one third
of all hard coral species are threatened with extinction, largely as a result of climate
change.
The IPCC identified coral reefs as a key example of a sector vulnerable to climate
change. Even at the lowest predicted threshold of temperature increase, coral bleaching
is expected. Reef scientists predict that “irreversible and catastrophic decline” of coral
reefs will occur with a warming of 1.7°C4 warming, less than the best-case global target
that seeks to keep warming at 2°C. Ocean acidification will accelerate the destruction of
coral reefs. At a meeting in London facilitated by the Royal Society, the Zoological
Society of London and the International Programme for the State of the Ocean, coral
scientists suggested inter alia that, as a result of both warming and ocean acidification “at
today’s level of 387ppm CO2, reefs are seriously declining and time-lagged effects will
result in their continued demise with parallel impacts on other marine and coastal
2
http://royalsociety.org/displaypagedoc.asp?id=34007
For additional information, see
http://www.interacademies.net/Object.File/Master/9/075/Statement_RS1579_IAP_05.09final2.pdf
4
Fischlin et al. 2007
3
ecosystems” and warned that “proposals to limit CO2 levels to 450ppm will not prevent
the catastrophic loss of coral reefs.”
Though I have focused my remarks today on the effects of ocean acidification on
organisms that fix calcium and carbonate as these provide the most studied and best
understood projected harmful effects of acidification, I will mention briefly other
projected harmful effects of acidifying oceans: It is projected that more acidic oceans
will conduct noise better, thus further interfering with marine life that depends on sound
to communicate. Most well understood are cetaceans, particularly whales that
communicate with each other over long distances by sound, by singing. Increased noise
from shipping and other human activities already restrict cetaceans’ abilities to
communicate. Acidification will exacerbate these effects. It is also projected that
acidifying oceans will cause the blood of some marine organisms to acidify, thus
reducing their ability to carry oxygen in their blood.
Why should this matter to us? The loss of hard coral species would have massive
consequences for reef biodiversity and for social and economic values of coral reefs
because these hard coral species serve as the foundation species for coral reef
ecosystems. Changes in fish abundance and location threaten to alter links that coastal
communities have developed over the centuries with marine resources in their area. The
oceans provide over fifteen per cent of the protein needs of almost half of the world’s
population and almost twenty per cent of total animal protein in low-income fooddeficient countries5. For many in developing countries, fish provide fifty per cent of
dietary protein. Thus, healthy fisheries are critical to the food security of many millions
of people. Fisheries provide employment and economic opportunities in many countries,
and are particularly important to helping to sustain coastal communities in developing
countries. Thus, ocean acidification, by interfering with marine biodiversity and current
patterns of marine life, threatens social and economic development for already vulnerable
coastal communities, particularly for the world’s poor.
So what can we do? First, clearly we need a good and strong commitment at
Copenhagen in December and beyond to cut sharply greenhouse gas emissions,
particularly those of carbon dioxide, into the atmosphere. The IPCC has suggested that in
order to limit temperature rise to no more than 2°C it will be necessary to keep CO2eq
levels at no more than 450 ppm. This in turn implies that UNFCCC Annex I countries
must reduce CO2eq emissions by over 80% by 2050. As there will remain a significant
lag between reductions of emissions into the atmosphere and reductions of take-up by
ocean waters, we actually need to begin reducing emissions earlier and more quickly.
Nevertheless, such cuts will not be enough to avoid further acidification. Even if we
ceased all carbon emissions now, the oceans would continue to acidify until such time as
the carbon balance between the oceans and the atmosphere is brought back into a natural
equilibrium. Thus, coral scientists suggest that we will have to reduce carbon dioxide
concentrations in the atmosphere to below their current levels, which average 387 ppm.
5
SOFIA 2008 pp. 3-4
However, there are steps that we can take now to improve the chances that the world’s
oceans will be able to adapt to the changes that they are facing and still supply services
on which the natural world, including us humans, depends. We need to promote healthy
marine ecosystems that will have resilience to face and adapt to change.
Environmental impact assessments are a tool to allow us to consider possible impacts of
our various activities before we undertake them. We need to implement assessment
processes and procedures with respect of fisheries and to include assessment of
cumulative impacts of human activities on the world’s oceans. We need to better
understand the science that drives nature through the more accurate and more transparent
collection of data with respect of fishing.
We need to implement marine spatial planning to help us to avoid a series of cumulative
impacts from a variety of actors on the same area of the ocean that will weaken or destroy
nature and natural systems. Marine spatial planning is a tool that should be used in
coastal areas and on the high seas. Marine protected areas, including marine reserves
where no extractive activities take place, will help to protect some ecosystems, thus
giving them a chance to evolve, to adapt, and to survive the changes caused by ocean
acidification. Marine reserves can provide a refuge where fish, including larger female
fish that produce exponentially more eggs, can shelter, thus ensuring healthier
ecosystems and better harvests for future generations. Protected areas should be
established by coastal states in areas subject to their jurisdiction and on the high seas,
either through existing arrangements or, if necessary, through new mechanisms or
arrangements, such as might be agreed at the United Nations General Assembly.
Parties to the Convention on Biological Diversity have adopted scientific criteria for
identifying ecologically or biologically significant marine areas in need of protection in
open-ocean waters and deep-sea habitats and scientific guidance for designing
representative networks of marine protected areas. It was agreed to convene an expert
workshop on scientific and technical guidance on the use of biogeographic classification
systems and identification of marine areas beyond national jurisdiction in need of
protection, which will take place in Ottawa later this month. This provides an
opportunity to identify areas especially worthy of protection on the high seas.
Another way to build resilience to help the oceans face the challenge of acidification is to
improve fisheries management. Though the FAO in its biennial State of World Fisheries
and Aquaculture Report (SOFIA Report) released in March 2009 noted that global trends
over the last ten to fifteen years in the state of world marine fish stocks have been
relatively stable, the state of certain keystone stocks is much graver. Large predator
species that act as critical regulators of ecosystems – tuna, sharks and others – have been
greatly overfished. Scientists report that many such stocks have declined by 90% from
historic levels. We need to listen to the scientists and accept their advice. Bluefin tuna
will essentially disappear from the Mediterranean in a few years if current rates of fishing
are not immediately reduced. Finning is a cause in the sharp reduction in the number of
sharks in the world’s oceans and is a practice that is both very harmful and wasteful. The
taking of large numbers – indeed almost whole schools – of small prey fish can also alter
ecosystems. Large schools of menhaden together with oysters used to filter all of the
water in the Chesapeake Bay every few days. That ecosystem no longer functions as it
did to provide clean water and healthy and abundant food for coastal communities. We
need to work as a global community to fully implement United Nations General
Assembly resolution 61/105 to protect vulnerable marine ecosystems from significant
adverse impacts of bottom fishing or not allow such fishing to proceed.
The United Nations Convention on the Law of the Sea serves as a constitution for the
oceans. Under article 192 of the Convention, States have accepted the obligation to
protect and preserve the marine environment6. Coastal states, taking into account the best
available scientific evidence are to ensure the proper conservation to protect living
resources from over-exploitation, including with respect of effects on associated or
dependent species.7 In areas beyond national jurisdiction, states have an obligation to
cooperate to conserve and manage living resources.8 States are to take measures to
prevent or control the introduction of alien species that may be harmful to a particular
part of the marine environment.9 States are to assess and report on the potential effects of
planned activities that may cause substantial pollution or significant harm to the marine
environment.10
We have a responsibility to ourselves, to our children and to other species with whom we
share our planet Earth to protect the oceans, including from the harmful effects of ocean
acidification. We must act responsibly to reach agreement this year in Copenhagen to
reduce sharply our greenhouse gas emissions. We must act responsibly here at meetings
in the United Nations, in the Food and Agriculture Organization and in regional fisheries
management bodies to manage fisheries in a way that is equitable and sustainable. We
must study, learn and teach about the oceans by promoting sound science. A Regular
process for global reporting and assessment of the state of the marine environment,
including socio-economic aspects will help to make that scientific knowledge available to
all and thus help us all to better manage the oceans for this and future generations.
Thank you.
6
See UNCLOS Art 192
See UNCLOS Art 61
8
See UNCLOS Art 118, also Art 119
9
See UNCLOS Art 196
10
See UNCLOS Art 206
7