Great Barrier Reef Experiencing A Mass Coral Bleaching Event
The management authority of the world’s largest coral reef system, Australia’s Great Barrier Reef, confirmed that the reef is experiencing a mass coral bleaching event due to high temperature. This is the sixth time that the coral reef system is being hit by a widespread and damaging bleaching event and the fourth time in six years that such an event has occurred. The bleaching event coincides with a 10-day UNESCO (United Nations Educational, Scientific and Cultural Organization) scientific mission currently underway in Australia.
Widespread serious bleaching was not seen until 1998, but with soaring greenhouse gas emissions heating the globe, it appears to now be a common occurrence.
Mass bleaching was again seen in 2002, 2016, 2017 and 2020. Bleaching occurs when the water is too warm, for too long. The coral expels the algae living inside it, leaving it colourless. The algae also provides the coral with most of its energy. If temperatures don't return to normal, the coral dies. Reefs can recover from bleaching, but it takes years. If bleaching occurs regularly, the reef ecosystem can collapse.
Coral reefs support over 25% of marine biodiversity, including fish, turtles and lobsters; even as they only take up 1% of the seafloor. The marine life supported by reefs further fuels global fishing industries. Even giant clams and whales depend on the reefs to live. Besides, coral reef systems generate $2.7 trillion in annual economic value through goods and service trade and tourism. In Australia, the Barrier Reef, in pre-COVID times, generated $4.6 billion annually through tourism and employed over 60,000 people including divers and guides. Aside from adding economic value and being a support system for aquatic life, coral reefs also provide protection from storm waves. Dead reefs can revive over time if there are enough fish species that can graze off the weeds that settle on dead corals, but it takes almost a decade for the reef to start setting up again. The reefs which were severely damaged in 1998 did recover over time.
The environmental group Greenpeace said the severe and widespread coral bleaching suffered during a La Niña weather pattern that is associated with cooler Pacific Ocean temperatures was evidence of the Australian government’s failure to protect the coral from the impacts of climate change. In July last year, Australia garnered enough international support to defer an attempt by UNESCO, the United Nations’ cultural organization, to downgrade the reef’s World Heritage status to “in danger“ because of damage caused by climate change.
But the question will be back on the World Heritage Committee’s agenda at its next annual meeting in June.
Scientists warn coral bleaching events will become more common as global warming intensifies, killing off coral reefs which will have run-on effects for the creatures living in the habitat, and local tourism industries. Last year, Australia controversially lobbied to exclude the reef from a Unesco list of World Heritage Sites that are "in danger". It has recently pledged money towards reef-protection measures, but critics said these did not address the dominant threat of climate change. A climate laggard among rich nations, Australia is often criticised for its strong support of fossil fuel industries. These repeated bleaching events have hit the tourism industry hard and are a blow to everyone who loves this incredible natural wonder, which is home to a vast array of sea creatures. While the Great Barrier Reef is being affected now, Reverter says it will be important to monitor other coral in the Pacific and Indian oceans in the coming months, to see whether heat stress triggers more widespread bleaching.
If global emissions continue unabated, Australia may warm by 4 degree Celsius or more this century. Under this scenario, widespread coral bleaching is likely on the Great Barrier Reef every year from 2044 onward. There has been some glimmers of hope in federal policy in recent years, such as statements recognising the existential threat climate change poses to coral reefs. Despite this recognition, substantial action is lacking, as any policy without action on climate change is ineffective. If the federal government, reef businesses and individuals are to show leadership and maintain healthy reefs, we need to work together and take rapid, drastic action to reduce carbon emissions.