The bleaching adds to Australia’s summer of unnatural calamities
OVER THE
southern hemisphere’s summer, mercifully now at an end, Australia
burned under a pitiless sun. Bush fires down the continent’s eastern
flank consumed 46m acres of countryside, destroying homes, taking lives
and driving rare animals towards extinction. To many Australians, the
satellite pictures showing huge plumes of smoke drifting off to the east
over the Great Barrier Reef seemed a portent of life in an age of
man-made warming.
It turns out that
high temperatures were wreaking havoc under the water as well. This
month comes news that exceptionally warm seas have led the Great Barrier
Reef, the world’s biggest coral system, to suffer its third mass
bleaching in five years. The bush and the reef, both ravaged on a
gargantuan scale: Australians almost define themselves by these two
ecosystems, which once seemed boundless.
Coral
bleaching takes place when sea temperatures spike, causing the coral
polyps that make up reefs to eject the algae that generate their food
via photosynthesis. Without the pigmented algae, coral soon dies,
leaving the intricate colonies a ghostly white. Reefs can recover from
occasional bleachings: the fastest-growing corals regenerate in a decade
or so. But mass bleachings on the Great Barrier Reef are becoming ever
more frequent. The first occurred only in 1998. There have since been
four more: in 2002, 2016, 2017 and now this year. They have become so
common that the Bureau of Meteorology issues forecasts for them.
The
latest bleaching is not as severe as the worst one, in 2016, when about
half of the northern part of the 2,300km-long reef died. But the run of
recent bleachings had already killed off relatively heat-intolerant
coral species. What is striking this year, says Terry Hughes of James
Cook University in Queensland, who led a recent aerial survey of the
reef, is that for the first time the bleaching extended to the southern
part of the reef. There, closer to the pole, waters should be cooler.
Not this year. February saw the highest sea-surface temperatures across
the reef since monitoring began 120 years ago.
The
biblical rains that recently extinguished the bush fires have also
helped to lower water temperatures over the reef. The rains are proof to
climate-change deniers—who are given a platform by Rupert Murdoch’s
press and who are represented on the ruling coalition’s backbenches—that
recent fires, droughts and floods are simply part of the natural cycle.
They point with glee to the bush springing back to life. Yet while
important habitats, such as those dominated by eucalypts, depend upon
fire to regenerate, this summer’s fires, exceptionally, destroyed
temperate rainforests too. They also incinerated perhaps a third of
koalas in New South Wales—hardly a run-of-the-mill dip in the
population.
Regarding the reef, the
deniers play down the damage and insist on the ability of “nature to fix
nature”. That is despite the cumulative effect of successive bleachings
from which reefs struggle to recover. Mr Hughes says the Great Barrier
Reef can no longer return to its state of even five years ago; in the
coming decades, healthy coral is likely to be confined to ever smaller
patches.
The bush fires threw the prime
minister, Scott Morrison, off balance. Holidaying in Hawaii made him
look out of touch, while his Liberal Party’s cosy links to oil, gas,
coal and iron-ore interests came under closer scrutiny. Among big
economies Australia ranks behind only Saudi Arabia in terms of
greenhouse-gas emissions per head—and that does not count the emissions
when its exports of coal and gas are consumed elsewhere.
Perhaps
in this respect, the new coronavirus is a tonic for Mr Morrison. His
polls, hurt by the fires, have risen as Australia has escaped an
epidemic on a par with Europe or America. Meanwhile, the government
intones it is on course to “meet and beat” national commitments under
the Paris agreement on climate to cut emissions—although that is thanks
in part to an accounting gimmick.
As
for the latest bleaching, the government has largely ignored the news.
Mr Morrison’s official “envoy” to the Great Barrier Reef, Warren Entsch,
a Queensland politician, points out that “bleached corals are not dead
corals” and predicts that many will recover. Although he admits climate
change is a concern, he once complained that “indoctrinating” youngsters
to be worried about it is a form of “child abuse”. Most Australians
care both about climate change and about the Great Barrier Reef—but not
enough, alas, to call their government out over such ambivalence.
Links
- More Than Half Of Remote Reefs In Coral Sea Marine Park Suffered Extreme Bleaching
- Great Barrier Reef's third mass bleaching in five years the most widespread yet
- Snow-white coral of once-vibrant Great Barrier Reef a sign urgent action must be taken
- Climate crisis may have pushed world's tropical coral reefs to tipping point of 'near-annual' bleaching
- Great Barrier Reef could face 'most extensive coral bleaching ever', scientists say
- Great Barrier Reef on brink of third major coral bleaching in five years, scientists warn
- Great Barrier Reef coral at risk of bleaching from Queensland flood waters
- Coral bleaching on Great Barrier Reef worse than expected, surveys show
- Great Barrier Reef at 'terminal stage': scientists despair at latest coral bleaching data
- Australia must choose between coal and coral – the Great Barrier Reef depends on it
No comments :
Post a Comment