Large areas of the Australian Great Barrier Reef are dying
The hot summer of the southern hemisphere
During the last summer of the southern hemisphere, Australia has burnt under an unforgiving sun. Forest fires have consumed 16 800 000 ha of land in the south-eastern part of the island, destroying 5900 houses, killing at least 33 people and at least one billion animals, bringing many rare species to the brink of extinction.
Unfortunately, the great heat has not only caused disasters on the surface but, it is now discovered, even more deeply, under the surface of the ocean. Australia boasts the largest coral reef in the world, the Great Barrier Reef which this year has faced the third wave of massive bleaching in just 5 years. The terrestrial and underwater ecosystem, which are symbols of the Australian continent, have both been indelibly compromised.
Massive whitening more and more frequent
The coral reef bleaching occurs when the water temperature reaches peaks and the corals expel the algae that generate their feeding through photosynthesis. Without pigmented algae, corals die quickly, transforming their intricate forest into a white uninhabited cemetery. The reefs can recover from occasional bleaching: the fastest growing corals take about ten years to regenerate.
But massive bleaching on the Great Barrier Reef is becoming more frequent. The first recorded occurred in 1998. There have been 4 more since then: in 2002, 2016, 2017 and last year’s. Last summer’s bleaching was not as devastating as the most tragic, the one of 2016, when almost half of the north side of the barrier, almost 2,300 km long, died.
Yet recent episodes have already killed many species that are particularly sensitive to heat. The thing that frightens researchers is that, for the first time, bleaching has also touched the southern part of the reef, the one closest to the pole, where, in theory, the water should be colder. Apparently, not this year: in February, the highest temperature of the ocean surface has been recorded since the measurements started, 120 years ago.
Between denial, political and economic interests
For those who deny climate change, the biblical rains that put out the fires and helped lower the sea temperature are proof that both heat waves and floods are simply part of the natural cycle. Hopeful, they showed us photos of vegetation ready to bloom again. But if it is true that entire ecosystems, such as that of eucalyptus trees, regenerate thanks to fire, it is equally true that last year's exceptional fires also devastated tropical forests that will not recover quickly and killed at least a third of the koalas in New South Wales.
When it comes to destroying the barrier, the deniers themselves downplay the problem and rely on nature's ability to recover and adapt. According to many researchers, however, the cumulative effects of recent bleaching episodes would be irrecoverable. The reef will never return to the same, and "healthy" corals will remain confined to smaller and smaller areas. Australia, among the world's major economies, ranks second as per capita greenhouse gas emissions, only beaten by Saudi Arabia. Not to mention the emissions caused by oil and coal exported abroad. Last year's fires were certainly an opportunity to put under a magnifying glass the close connections between the Liberal Party of the Australian premier, Scott Morrison, and the major oil, coal and gas industries... Needless to say that in front of certain interests, it is a struggle to find someone who would listen to the requests of corals, fish, koalas, eucalyptus and the rest of the Australian ecosystem.