Last week, Australia's Great Barrier Reef suffered massive bleaching due to a rise in sea temperature; an unfortunate consequence of climate change and global warming. Water temperatures had been 4C° above March average. This was its 6th bleaching, having first experienced mass bleaching in 1998.
Corals and their importance
Corals are actually animals, marine invertebrates which form a hard skeleton made of limestone. They live in colonies, forming reefs; the most notable of all is the Great Barrier Reef Australia. A great wonder of nature and a UNESCO World Heritage site, the Great Barrier reef off Australia's coast is amongst the most biodiverse ecosystems on the planet, home to thousands of marine species, including endangered species like the large green turtle. Most of today's reefs are 5000 to 10 000 years old, whilst the eldest of today's reefs started growing up to 50 million years ago. Coral reefs are important; they are a natural habitat to countless species, a significant ocean structure helping reduce coastal erosion of cliffs and beaches, provide plenty of fish which are a source of income and food for local communities, are used as an ingredient in some medicines, and also contributes to tourism as one of Australia's favourite spots, creating jobs and income for local communities.
What is coral bleaching?
Naturally algae live inside the corals, giving the coral not only their beautiful colour, but also providing the primary source of nutrients it needs to live and grow.
Bleaching occurs due to abnormal temperature changes in the sea (too low or too high) or changes in the ocean like acidification, causing corals 'get stressed' and expel the algae that provides it life and colour. The coral is hence bleached (turned white) and left very vulnerable, at risk of dying. If normal temperatures do not return within 8 weeks, bleached corals often die. Although it’s possible for corals to recover, it’s a long process of decades, and many don't recover, wiping out ecosystems - since the marine life either move away or die.
Why is it in danger?
Recent high temperatures due to global warming has caused more than half of the Great Barrier reef to bleach. Global warming significantly increases risk of mass bleaching, making our reefs more susceptible than ever to this phenomenon. Since 2016, the Great Barrier Reef has suffered 2 bleaching’s, and about half of the coral has been lost since 1995 due to rising sea temperatures. Human activity like coastal development and agricultural pollutants too pose great threat to the reef.
Efforts to save the reef
Governments have recognised the pertinence of this issue, with Australia that has said to have spent $2.2 billion to protect the reef - by concentrating efforts on cutting greenhouse gas emissions, improving agricultural practices, and preventing farming chemicals from being dumped into the reef. Some countries have been making coral nurseries, helping regrow damaged reefs.
However, this is not enough. More urgent action is needed. Despite Australia's pledges to protect the reef, they did not address actions against climate change; they haven't committed to net zero emissions target for 2050 either, as various other countries have done so. Australia still remains a supporter of fossil fuel industries. Greenhouse emissions and fossil fuel usage need to be significantly reduced to slow down or even reverse the horrifying effects of global warming.
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Written by Sanika Srivastava