Environmental threats to the Great Barrier Reef

This article needs to be updated. The reason given is: new state of the environment report https://www.theguardian.com/environment/2022/jul/19/labor-says-it-wont-put-head-in-the-sand-as-it-releases-shocking-environment-report, new plan https://www.smh.com.au/environment/climate-change/critics-pan-a-plan-for-the-barrier-reef-as-bleaching-threat-rises-20211222-p59jk9.html and 6th mass bleaching https://www.abc.net.au/news/2022-05-11/queensland-great-barrier-reef-bleaching-report/101056520. Please help update this article to reflect recent events or newly available information. (December 2021)

The Great Barrier Reef is the world's largest reef systems, stretching along the East coast of Australia from the northern tip down at Cape York to the town of Bundaberg,^[1][2] is composed of roughly 2,900 individual reefs and 940 islands and cays that stretch for 2,300 kilometres (1,616 mi) and cover an area of approximately 344,400 square kilometres (133,000 sq mi).^[3][4] The reef is located in the Coral Sea, off the coast of Queensland in northeast Australia. A large part of the reef is protected by the Great Barrier Reef Marine Park.

According to the 2014 report of the Australian Government's Great Barrier Reef Marine Park Authority (GBRMPA), says that climate change is the most significant environmental threat to the Great Barrier Reef,^[5] while the other major environmental pressures are listed as decreased water quality from land-based runoff, impacts from coastal development and some persistent impacts from fishing activities. The reef is also threatened by storms, coral bleaching and ocean acidification.^[6][7][8] The 2014 report also shows that, while numerous marine life species have recovered after previous declines, the strength of the dugong population is continuing to decline.^[9] Terry Hughes, Federation Fellow, ARC Centre of Excellence for Coral Reef Studies at James Cook University, wrote in a 14 August 2014 Conversation piece that harmful government policies and ongoing conflicts of interest over mining royalties are risks of an equivalent magnitude.^[10]

The GBRMPA consider climate change, poor water quality, coastal development, and some impacts from fishing to be the area's major threats, but reef scientists Jon Day, Bob Pressey, Jon Brodie and Hughes stated that the "cumulative effects of many combined impacts" is the real issue.^[11]

In a Conversation article,^[12] Mathieu Mongin, a biogeochemical modeller at CSIRO and colleagues mapped parts of the Great Barrier Reef that are most exposed to ocean acidification. This map of pH on the Great Barrier Reef presents the exposure to ocean acidification on each of the 3,581 reefs, providing managers with the information they need to tailor management to individual reefs. The Great Barrier Reef is not a singular reef nor a physical barrier that prevents exchange between reefs; it is a mixture of thousands of productive reefs and shallow areas lying on a continental shelf with complex oceanic circulation.

In March 2022, UNESCO launched a monitoring mission to assess the impact of pollution, fishing, climate change and coral bleaching. The report concluded that the Great Barrier Reef should be included on the list of World Heritage in Danger, which would probably have had an impact on tourism. In May 2023, after years of warnings from UNESCO, Australian Environment Minister Tanya Plibersek promised in a letter to UNESCO Director Audrey Azoulay a "combined investment of A$4.4 billion" to protect the reef. In the letter, Australia committed to following UNESCO's recommendations, creating no-fishing zones in one third of the site by the end of 2024, completely banning gillnetting by 2027 and meeting targets for improving water quality by 2025. The Albanese government has pledged to set targets for reducing CO2 emissions, in order to align with the objective of limiting global temperature rise to 1.5 °C.^{[13][14][15][16]}