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FORT
LAUDERDALE, US—One-third of reef-building corals already
face extinction because of climate change, the
first-ever global assessment has found.
Reefs
are made up of hundreds of coral species, and a two-year
study to determine the current status of corals has
discovered that 231 of the 704 species assessed will be
“red-listed.” This means these 231 species meet the
International Union for Conservation of Nature (IUCN)
Red List Criteria for species at risk of extinction in
the near future.
Previously, only 10 species of corals had been
red-listed, mainly because no proper assessment had been
done before.
“We were
not expecting the numbers to be that high,” said Suzanne
Livingstone of the IUCN’s Global Marine Species
Assessment (GMSA) in Norfolk, Virginia. The paper was
published Thursday in Science.
If the
same assessment of corals had been done 20 years ago,
only 13 of the 704 species would have been red-listed,
Livingstone told Inter Press Service (IPS) at the 11th
International Coral Reef Symposium (ICRS) in Fort
Lauderdale, Florida. However, in that short time span,
climate change has warmed the oceans and begun to make
them more acidic and corals are suffering.
“It’s
frightening when you think about it,” she said.
Coral
reefs are often called the rain forests of the oceans
for the richness of species they harbor, representing 25
percent to 30 percent of all marine species. Millions of
people, including many in developing countries, derive
their livelihoods from fishing, while around 2.6 billion
people get their protein from seafood, according to
studies done by the United Nations Environment Programme
(Unep).
Coral
reefs also help mitigate beach erosion and have high
recreation value for tourism. Unep estimates that a
typical coral reef can absorb up to 90 percent of the
energy of wind-generated waves, thus protecting coastal
areas from damage.
The
economic value of reefs globally is estimated at $375
billion, Brian Huse, executive director of the Coral
Reef Alliance, a US-based nongovernment organization
dedicated to protecting the health of coral reefs, told
IPS in a previous interview.
“When
corals die off, so do the other plants and animals that
depend on coral reefs for food and shelter, and this can
lead to the collapse of entire ecosystems,” said Kent
Carpenter, lead author of the Science article, GMSA
director, IUCN Species Program.
The rate
at which corals are approaching extinction is far faster
than any previous extinction event in Earth’s history,
Carpenter told IPS. “It’s the most alarming finding for
biodiversity in the marine realm,” he said, adding that
only amphibians are at greater risk, also due to climate
change.
Staghorn
corals face the highest risk of extinction, with 52
percent of species listed in a threatened category. The
Caribbean region has the highest number of highly
threatened corals (endangered and critically
endangered), including the iconic elkhorn coral (Acropora
palmata), which is listed as critically endangered.
The high
biodiversity “Coral Triangle” in the western Pacific’s
Indo-Malay-Philippine Archipelago has the highest
proportions of vulnerable and near-threatened species in
the Indo-Pacific, largely resulting from the high
concentration of people living in many parts of the
region.
Not all
of the world’s 845 reef-building corals could be
assessed. Carpenter says there wasn’t enough data to
evaluate how 141 species are doing.
While
climate change is the primary global threat because it
warms ocean temperatures beyond corals’ heat tolerance,
pollution and overfishing are also major stressors that
amplify and accelerate the impact.
Another
problem for corals is ocean acidification. However,
since scientists only recently discovered that carbon
emissions from burning of fossil fuels are turning the
oceans more acidic, it hasn’t been fully assessed in
this study, said Livingstone.
“Ultimately it is a combination of all these impacts on
corals,” she said.
Red-listing does not mean a species will become extinct,
but it does mean that if the conditions that are
threatening corals continue or worsen, then they may
very well become extinct.
The IUCN
Red List is the widely accepted gold standard for
determining which species are at risk. It has eight
levels of risk ranging from no risk to critically
endangered. The 231 coral species are in the “critically
endangered,” “endangered” or “vulnerable” categories.
The
results emphasize the widespread plight of coral reefs
and the urgent need to enact conservation measures, said
Julia Marton-Lefèvre, IUCN director general.
“We
either reduce our CO2 emissions now or many corals will
be lost forever,” Marton-Lefèvre said in a statement. |
