[Marxism] Large Sections of Australia’s Great Reef Are Now Dead, Scientists Find
lnp3 at panix.com
Thu Mar 16 06:55:46 MDT 2017
NY Times, Mar. 16 2017
Large Sections of Australia’s Great Reef Are Now Dead, Scientists Find
By DAMIEN CAVE and JUSTIN GILLIS
SYDNEY, Australia — The Great Barrier Reef in Australia has long been
one of the world’s most magnificent natural wonders, so enormous it can
be seen from space, so beautiful it can move visitors to tears.
But the reef, and the profusion of sea creatures living near it, are in
Huge sections of the Great Barrier Reef, stretching across hundreds of
miles of its most pristine northern sector, were recently found to be
dead, killed last year by overheated seawater. More southerly sections
around the middle of the reef that barely escaped then are bleaching
now, a potential precursor to another die-off that could rob some of the
reef’s most visited areas of color and life.
“We didn’t expect to see this level of destruction to the Great Barrier
Reef for another 30 years,” said Terry P. Hughes, director of a
government-funded center for coral reef studies at James Cook University
in Australia and the lead author of a paper on the reef that is being
published Thursday as the cover article of the journal Nature. “In the
north, I saw hundreds of reefs — literally two-thirds of the reefs were
dying and are now dead.”
The damage to the Great Barrier Reef, one of the world’s largest living
structures, is part of a global calamity that has been unfolding
intermittently for nearly two decades and seems to be intensifying. In
the paper, dozens of scientists described the recent disaster as the
third worldwide mass bleaching of coral reefs since 1998, but by far the
most widespread and damaging.
The state of coral reefs is a telling sign of the health of the seas.
Their distress and death are yet another marker of the ravages of global
If most of the world’s coral reefs die, as scientists fear is
increasingly likely, some of the richest and most colorful life in the
ocean could be lost, along with huge sums from reef tourism. In poorer
countries, lives are at stake: Hundreds of millions of people get their
protein primarily from reef fish, and the loss of that food supply could
become a humanitarian crisis.
With this latest global bleaching in its third year, reef scientists say
they have no doubt as to the responsible party.
They warned decades ago that the coral reefs would be at risk if human
society kept burning fossil fuels at a runaway pace, releasing
greenhouse gases that warm the ocean. Emissions continued to rise, and
now the background ocean temperature is high enough that any temporary
spike poses a critical risk to reefs.
“Climate change is not a future threat,” Professor Hughes said. “On the
Great Barrier Reef, it’s been happening for 18 years.”
Corals require warm water to thrive, but they are exquisitely sensitive
to extra heat. Just two or three degrees Fahrenheit of excess warming
can sometimes kill the tiny creatures.
Globally, the ocean has warmed by about 1.5 degrees Fahrenheit since the
late 19th century, by a conservative calculation, and a bit more in the
tropics, home to many reefs. An additional kick was supplied by an El
Niño weather pattern that peaked in 2016 and temporarily warmed much of
the surface of the planet, causing the hottest year in a historical
record dating to 1880.
It was obvious last year that the corals on many reefs were likely to
die, but now formal scientific assessments are coming in. The paper in
Nature documents vast coral bleaching in 2016 along a 500-mile section
of the reef north of Cairns, a city on Australia’s eastern coast.
Bleaching indicates that corals are under heat stress, but they do not
always die and cooler water can help them recover. Subsequent surveys of
the Great Barrier Reef, conducted late last year after the deadline for
inclusion in the Nature paper, documented that extensive patches of reef
had in fact died, and would not be likely to recover soon, if at all.
Professor Hughes led those surveys. He said that he and his students
cried when he showed them maps of the damage, which he had calculated in
part by flying low in small planes and helicopters.
His aerial surveys, combined with underwater measurements, found that 67
percent of the corals had died in a long stretch north of Port Douglas,
and in patches, the mortality reached 83 percent.
By luck, a storm stirred the waters in the central and southern parts of
the reef at a critical moment, cooling them, and mortality there was
much lower — about 6 percent in a stretch off Townsville, and even lower
in the southernmost part of the reef.
But an Australian government study released last week found that over
all, last year brought “the highest sea surface temperatures across the
Great Barrier Reef on record.”
Only 9 percent of the reef has avoided bleaching since 1998, Professor
Hughes said, and now, the less remote, more heavily visited stretch from
Cairns south is in trouble again. Water temperatures there remain so
high that another round of mass bleaching is underway, the Great Barrier
Reef Marine Park Authority confirmed last week.
Professor Hughes said he hoped the die-off this time would not be as
serious as last year’s, but “back-to-back bleaching is unheard-of in
Australia.” The central and southern part of the reef had already been
badly damaged by human activities like dredging and pollution.
The Australian government has tried to combat these local threats with
its Reef 2050 plan, restricting port development, dredging and
agricultural runoff, among other risks. But Professor Hughes’s research
found that, given the high temperatures, these national efforts to
improve water quality were not enough.
“The reefs in muddy water were just as fried as those in pristine
water,” Professor Hughes said. “That’s not good news in terms of what
you can do locally to prevent bleaching — the answer to that is not very
much at all. You have to address climate change directly.”
With the election of Donald J. Trump as the American president, a recent
global deal to tackle the problem, known as the Paris Agreement, seems
to be in peril. Australia’s conservative government also continues to
support fossil fuel development, including what many scientists and
conservationists see as the reef’s most immediate threat — a proposed
coal mine, expected to be among the world’s largest, to be built inland
from the reef by the Adani Group, a conglomerate based in India.
“The fact is, Australia is the largest coal exporter in the world, and
the last thing we should be doing to our greatest national asset is
making the situation worse,” said Imogen Zethoven, campaign director for
the Australian Marine Conservation Society.
Australia relies on the Great Barrier Reef for about 70,000 jobs and
billions of dollars annually in tourism revenue, and it is not yet clear
how that economy will be affected by the reef’s deterioration. Even in
hard-hit areas, large patches of the Great Barrier Reef survived, and
guides will most likely take tourists there, avoiding the dead zones.
The global reef crisis does not necessarily mean extinction for coral
species. The corals may save themselves, as many other creatures are
attempting to do, by moving toward the poles as the Earth warms,
establishing new reefs in cooler water.
But the changes humans are causing are so rapid, by geological
standards, that it is not entirely clear that coral species will be able
to keep up. And even if the corals do survive, that does not mean
individual reefs will continue to thrive where they do now.
Coral reefs are sensitive systems, built by unusual animals. The corals
themselves are tiny polyps that act like farmers, capturing colorful
single-celled plants called algae that convert sunlight into food. The
coral polyps form colonies and build a limestone scaffolding on which to
live — a reef.
But when the water near a reef gets too hot, the algae begin producing
toxins, and the corals expel them in self-defense, turning ghostly
white. If water temperatures drop soon enough, the corals can grow new
algae and survive, but if not, they may succumb to starvation or disease.
Even when the corals die, some reefs eventually recover. If water
temperatures stay moderate, the damaged sections of the Great Barrier
Reef may be covered with corals again in as few as 10 or 15 years.
But the temperature of the ocean is now high enough that global mass
bleaching events seem to be growing more frequent. If they become
routine, many of the world’s hard-hit coral reefs may never be able to
Within a decade, certain kinds of branching and plate coral could be
extinct, reef scientists say, along with a variety of small fish that
rely on them for protection from predators.
“I don’t think the Great Barrier Reef will ever again be as great as it
used to be — at least not in our lifetimes,” said C. Mark Eakin, a reef
expert with the National Oceanic and Atmospheric Administration, in
Silver Spring, Md.
Dr. Eakin was an author of the new paper and heads a program called
Coral Reef Watch, producing predictive maps to warn when coral bleaching
is imminent. Even though last year’s El Niño has ended, water
temperatures are high enough that his maps are showing continued hot
water across millions of square miles of the ocean.
Kim M. Cobb, a climate scientist at the Georgia Institute of Technology
who was not involved in the writing of the new paper, described it and
the more recent findings as accurate, and depressing. She said she saw
extensive coral devastation last year off Kiritimati Island, part of the
Republic of Kiribati several thousand miles from Australia and a place
she visits regularly in her research.
With the international effort to fight climate change at risk of losing
momentum, “ocean temperatures continue to march upward,” Dr. Cobb said.
“The idea that we’re going to have 20 or 30 years before we reach the
next bleaching and mortality event for the corals is basically a fantasy.”
Damien Cave reported from Sydney, and Justin Gillis reported from New York.
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