From: NY Times
Published January 30, 2009 09:10 AM
Rising Acidity Threatens Oceans
The oceans have long buffered the effects of
climate change by absorbing a substantial portion of the greenhouse gas
carbon dioxide. But this benefit has a catch: as the gas dissolves, it makes
seawater more acidic. Now an international panel of marine scientists says
this acidity is accelerating so fast it threatens the survival of coral
reefs, shellfish and the marine food web generally.
The panel, comprising 155 scientists from 26 countries and organized by the
United Nations and other international groups, is not the first to point to
growing ocean acidity as an environmental threat, but its blunt language and
international credentials give its assessment unusual force. It called for
“urgent action”� to sharply reduce emissions of carbon dioxide.
“Severe damages are imminent,” the group said Friday in a statement
summing up its deliberations at a symposium in Monaco last October.
The statement, called the Monaco Declaration, said increasing acidity is
interfering with the growth and health of shellfish and eating away at coral
reefs, processes that would eventually affect marine food webs generally.
Already, the group said, there have been detectable decreases in
shellfish, shell weights and interference with the growth of coral
skeletons.
Jeremy B. C. Jackson, a coral expert at the Scripps Institution of
Oceanography in San Diego, said “there is just no doubt” that the
acidification of the oceans is a major problem. “Nobody really focused on it
because we were all so worried about warming,” he said, “but it is very
clear that acid is a major threat.”
Carbon dioxide, principally from the burning of fossil fuels, is the major
component of greenhouse gas emissions, which have risen steadily since the
beginning of the industrial revolution in the 18th century.
Oceans absorb about a quarter of carbon dioxide emissions, the group said,
but as the gas dissolves in the oceans it produces carbonic acid.
The group said acidity of ocean surface waters has increased by 30 percent
since the 17th century.
“The chemistry is so fundamental and changes so rapid and severe that
impacts on organisms appear unavoidable,” according to James Orr, who headed
the symposium’s scientific committee. Dr. Orr is a chemical oceanographer at
the Marine Environmental Laboratory in Monaco, an affiliate of the
International Atomic Energy Agency, a United Nations body.
According to the declaration, “ocean acidification may render most regions
chemically inhospitable to coral reefs by 2050.” The group said that
acidification can be controlled only by limiting future atmospheric levels
of the gas. Other strategies, including “fertilizing” the oceans to
encourage the growth of tiny marine plants that take up carbon dioxide might
actually make the problem worse in some regions, it said.
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