Great Barrier Reef Corals Victims of Global Warming
BRISBANE, Australia, February 25, 2004 (ENS) - Global warming is causing the corals of the Great Barrier Reef
to bleach and die, and new research by an Australian team shows that under a worst case scenario the coral
populations on the world’s longest reef will collapse by 2100.
WWF Australia and the Queensland Tourism Industry Council, who commissioned the
study, released the comprehensive report Saturday on how Australia’s Great
Barrier Reef may look in an overheating world.
After two years of research incorporating climate sciences, biology and the economics of Australia’s
coral reef industries, the father-son team of economist Hans Hoegh-Guldberg and reef scientist Ove
Hoegh-Guldberg conclude that the reef is headed for serious damage even if humans do all the right
things, and the natural and human communities that depend on the reef will also suffer major losses.
Bleaching of some Great Barrier Reef inshore reefs could be seen from the air during the mass bleaching
event of 1998.
Their report, “Implications of Climate Change for Australia’s Great Barrier Reef,” shows that under the
best case scenario the loss is recoverable only if global temperature increases remain below two degrees.
Under the worst case scenario, coral populations will collapse by 2100 and the
re- establishment of coral reefs will be “highly unlikely over the following
200-500 years,” the Hoegh-Guldbergs say.
Human driven climate change is a fact, they write. ”It is here right now and is already changing our lives. It
will continue to do so for many hundreds of years.”
The only way a worst case scenario on the Great Barrier Reef can be avoided is if
humans can rapidly switch to clean, renewable energy sources, limiting the
heat-trapping greenhouse gases emitted by the burning of fossil fuels - coal, oil and natural gas.
“Coral reefs are one of the first major casualties of climate change,” said Ove
Hoegh- Guldberg, director of the University of Queensland professor and co-author of
the report. “The only hope we have of saving these beautiful ecosystems lies in massively reducing
heat-trapping gas emissions and stabilizing the Earth’s climate within two degrees Celsius of pre-industrial
Hoegh-Guldberg, who was awarded a Eureka Prize in 1999 for his work on the cause of mass coral bleaching,
explains that when corals are exposed to stressful conditions, like waters that are too warm, they lose
the colorful symbiotic algae necessary to their
continued health and survival.
“The broad scale of these events and the fact that they are triggered by episodes of warmer than normal water
has generated international concern over the potential link to greenhouse warming trends,” he said.
“There is no longer any serious doubt,” he writes, “that the Earth has warmed by 0.6 to 0.8 degrees
Celsius since 1880 and will warm a further two to six degrees Celsius by 2100, almost exclusively due to
Coral bleaching events began in 1979, and since then reports of global cycles of mass coral bleaching have
only increased. “The global episode of mass coral bleaching in 1998 was the largest in recorded history,
and coincided with the warmest year and decade on
record. It removed an estimated 16 percent of the world’s living coral, with estimates for the Indian
Ocean rising as high as 46 percent of living coral dying over a few months,” the Hoegh-Guldbergs write.
The Great Barrier Reef Marine Park Authority which governs the reef says that the mass bleaching event in
the summer of 2002 affected between 60 and 95 percent of reefs in the Marine Park, the worst bleaching event
ever recorded there. While most reefs that were
surveyed survived with relatively low levels of coral death, some locations suffered severe damage with up to
90 percent of corals killed.
Around the world coral reefs are suffering from a combination of coastal land practices, overfishing and
marine based pollution, warns the report. “These influences alone have been estimated to potentially
remove over 50 percent of coral reefs over the next 30
to 50 years.”
Reduced carbonate alkalinity of seawater, the source of ions for calcification, is inflicting additional
pressure on coral reefs.
Hoegh-Guldberg calls Australia’s Great Barrier Reef “the best-managed reef ecosystem in the world,” but all
the management in the world does not prevent it from being threatened by warming sea temperatures.
“The facts supporting these conclusions are indisputable,” he states. The Great Barrier Reef
experienced mass coral bleaching events in 1998 and 2002.
Corals on the Great Barrier Reef will experience between two and six degrees Celsius increases in sea
temperature by 2100. Thermal stress is likely to increase to levels that are several times higher than
in 1998. By the middle of this century, these levels will be exceeded every year at all sites along the
Great Barrier Reef.
“Corals will either have to adapt or move. If they don’t do either, then corals will become rare over most
of the Great Barrier Reef,” he writes.
Corals, used to evolving in a timeframe of centuries and millenia, just will not be able to adapt quickly
enough, and they will disappear.
“Reefs will not disappear,” Hoegh-Guldberg writes, “but they will be devoid of coral and dominated by other
less appealing species such as macroalgae and cyanobacteria.”
To address these issues, the authors recommend that Australia ratify the Kyoto Protocol and help to
persuade the United States to do likewise.
This international treaty under the UN Framework Convention on Climate Change requires 37 industrialized
countries to reduce their emission of six greenhouse gases an average of 5.2 percent of 1990 levels during
the five year period 2008 to 2012 known as the first
When President George W. Bush took office, the United States has backed away from the protocol originally
signed under President Bill Clinton. With about five percent of the world’s population, the United States
emits some 22 percent of the world’s greenhouse gases.
Australia followed suit although the protocol would have permitted Australia to increase its greenhouse gas
emissions by eight percent during the 2008 to 2012 period. Although meeting the Kyoto targets requires major
changes is energy generation and consumption, many experts say even that level of greenhouse gas
reductions will only reduce the warming of the planet by a fraction of what is needed to avert ecological
Staghorn corals on the northern reef slope of Heron Island, are most affected by
blea- ching, scientists have observed. The Hoegh-Guldbergs recommend that the Australian
government work on ways to “achieve deeper cuts in greenhouse gas emissions in the second commitment
period of the Kyoto Protocol. This discussion would address the development needs of developing countries
as well as acknowledging the need for emissions to be slowed throughout the world.”
The Australian government can take a positive role in promoting and helping to fund the replacement of oil
and coal based energy technologies with clean, renewable and affordable energy sources in developing
countries, the authors suggest.
Developing coutries with large outputs of greenhouse gases such as China, India and Brazil have ratified the
Kyoto Protocol, but their emissions will not be governed until the second commitment period from 2012
onward, and negotiations on these limits have not yet begun.
The Australian Government’s national Mandatory Renewable Energy Target is “an excellent initiative”
but it should be strengthened, to 10 percent renewable energy gene-
ration by 2010. That would not only assist in turning the tide in the battle with carbon dioxide
emissions but could also have net benefits for rural and regional Australia, they say.
The report’s authors would like to see Australia set a national target for the uptake of co-generation of heat
and power for large industrial energy users which they say would provide an incentive for some of the biggest
users of coal fired electricity to also install gas fired generators.
They want state governments, which are responsible for the future direction of Australia’s electricity
infrastructure, to ensure that any new fossil fuel power stations be required to meet best practice
emissions intensity at the level of a combined cycle gas turbine.
Australia should impose mandatory energy efficiency standards for all new and existing buildings. Energy
performance standards for appliances and equipment should also be tightened and a levy placed on
appliances that waste energy, Hoegh-Guldberg writes.
The authors suggest a national carbon tax or national greenhouse gas emissions trading scheme with a tight
cap on emissions and auctioning of tradeable permits as “a very positive step to reduce greenhouse emissions
using market mechanisms.”
To reduce emissions from the transportation sector all levels of government must substantially increase
funding for public transport and rail freight and introduce mandatory fuel efficiency standards for new
cars and commercial vehicles, the authors advise.
Large scale land clearing should be “brought to an immediate end” with regulation and incentives and
revegetation programs should be vigorously pursued, they say, because vegetation absorbs carbon dioxide to
some extent, although recent studies have raised
questions about how efficient that absorption is.
Over the past few days, the Hoegh-Guldbergs have been in Canberra briefing government ministers about the
contents of their report, and they have been well received.
Environment Minister David Kemp told the “Sydney Morning Herald” that the report is a good contribution
to debate about the reef from a constructive organization, but he did not immediately reach for his
pen to sign the Kyoto Protocol.
The Hoegh-Guldbergs are not optimistic about the fate of the Great Barrier Reef, even if all their
recommendations are quickly adopted. Even if global warming is limited to 2.5 degrees Celsius, they warn,
the world’s coral reefs are likely to experience widespread and serious damage.
© Copyright Environment News Service (ENS) 2004. All Rights