Ove Hoegh-Guldberg talks with
ScienceWatch.com and answers a few questions about
this month's New Hot Paper in the field of
Article Title: Coral reefs under rapid climate
change and ocean acidification
O, et al.
Year: DEC 14 2007
* Univ Queensland, Ctr Marine Studies, St Lucia, Qld 4072,
* Univ Queensland, Ctr Marine Studies, St Lucia, Qld 4072,
* Univ Exeter, Sch Biosci, Marine Spatial Ecol Lab, Exeter
EX4 4PS, Devon, England.
(addresses have been truncated)
Why do you think your paper is highly
The paper focuses on the issue of coral reefs and climate change,
synthesizing our current understanding of past, present, and future
trajectories for these biologically diverse marine ecosystems. I believe
that this paper has attracted a lot of attention given the importance of
coral reefs to over 100 million people worldwide, and given that the paper
summarizes the latest science on how these ecosystems are and will be
impacted by climate change.
The paper has also had policy significance, in that it has contributed to
the debate on the stabilization targets for atmospheric carbon dioxide. In
the latter case, it makes the point very plainly that exceeding atmospheric
carbon dioxide levels of more than 450 parts per million (ppm) will trigger
the loss of coral reefs (and a lot more).
Does it describe a new discovery, methodology, or
synthesis of knowledge?
Primarily, it is a synthesis of the science gained over the past decade,
which has been marred by the increasing destruction of reefs by rapid
anthropogenic climate change. In addition to the loss of Arctic sea ice,
coral reefs represent an early example of the scale and intensity with
which climate is likely to affect natural ecosystems and processes
"In addition to the problems of
reducing emissions, there will almost
certainly be major changes to natural
ecosystems, such as coral
One of the major outcomes of the paper is the
conclusion—convincingly, we would argue—that increasing carbon
dioxide levels above 450 ppm will cause coral-dominated reef ecosystems to
disappear. Synthesizing the available science and coming to this conclusion
(i.e., 450 ppm is the absolute upper limit for stabilization) has not been
done in a single place before.
Would you summarize the significance of your paper
in layman's terms?
This paper summarizes the last 10 years of science on how coral reefs are
being affected by climate change. In doing so, it reveals the enormous risk
that we take with the world's most biologically diverse marine ecosystem,
and in doing so, highlights the extreme danger that we face with respect to
all human and natural systems if we push carbon dioxide well beyond where
it has a been during the past 20 million years.
The identification of the critical stabilization point of 450 ppm has
attracted a lot of interest from policymakers, who are looking to
scientists for advice on where these targets for atmospheric CO2
must lie. In this respect, the implications of this paper have now been fed
into national and international negotiations on several occasions already.
How did you become involved in this research, and
were there any problems along the way?
Many of the authors on this paper have been involved in research associated
with the biology of coral for many decades. Most of them have come to this
area of research at the same time, as there has been increasing evidence
that local concerns—pollution, fishing—and global
issues—rising sea levels, temperatures, and acidities—are
seriously impacting coral reef ecosystems.
The paper also discusses the link between local stresses arising from human
activities such as coastal development, urbanization, and over-fishing, and
global climate change. The interrelationship between the two stresses has
highlighted the importance of dealing with both, and the opportunity that
exists to buy important time for coral reefs while we struggle to get
global emissions under control. For example, time can be bought for reefs
by maintaining healthy populations of herbivorous fish, which in turn
control seaweeds and give corals a better chance of bouncing back from
impacts like mass coral bleaching and mortality. And so on.
Where do you see your research leading in the
The next big sets of questions are those associated with the solutions that
we need to apply to the challenges of rapid anthropogenic climate change.
In some ways, this is going to be a more difficult area than that
associated with the initial identification of the problems. For example, we
recently formed an expert group to explore whether or not current ecosystem
management tools were adequate enough to match the enormous challenges that
climate change imposes on natural ecosystems such as coral reefs and other
Our conclusion (O Hoegh-Guldberg, et. al., "Assisted Colonization
and Rapid Climate Change" Science 321:345–46, July 2008) was
that many of the so-called traditional tools were now ineffective under
rapid climate change. The questions such as whether or not we should move
species and ecosystems critically endangered by a rapidly moving climate
are currently unanswered and form an important frontier for future
research. Trying to understand more about the interaction and synergies
associated with climate factors will also be increasingly important as we
tried to pre-empt the "surprises" and non-linear changes that are almost
certain to occur over the coming decades and century of stress.
Do you foresee any social or political implications
for your research?
As discussed above, there are many social and political implications of our
research. In identifying the problems associated with exceeding atmospheric
carbon dioxide concentrations of 450 ppm, research such as ours has
essentially thrown out an enormous challenge to policymakers and other
specialists such as the economists.
Stabilization at 450 ppm will require deep and immediate cuts in carbon
dioxide emissions, such that emissions need to be in decline globally
within 10 years time. As has been seen from recent discussions, this will
be far from easy. In addition to the problems of reducing emissions, there
will almost certainly be major changes to natural ecosystems, such as coral
reefs, as climate change that is in the pipeline (so to speak) rolls
through the system. In this respect, there will be continued deterioration
of coral reefs by thermal stress (bleaching) and ocean acidification, with
implications for the estimated hundred million people that depend on them
daily, and the billion-dollar tourist and fishery industries associated
with coral reefs.
Professor and Director
Centre for Marine Studies
The University of Queensland
St. Lucia, Australia