The outlook for Australia’s Great Barrier Reef has been downgraded from ‘poor’ to ‘very poor’ due to warming oceans.
A new report, updated every five years by the Great Barrier Reef Marine Park Authority, states that the greatest threat to the 133,360sq mile coral network remains as climate change.
The colourful natural wonder positioned off the north-east Australian coast has faced significant bleaching in recent years thanks to rising sea temperatures, whilst further threats associated with coastal development, land-based water run-off, and human activity such as illegal fishing take their toll.
“Significant global action to address climate change is critical to slowing the deterioration of the reef’s ecosystem and heritage values and supporting recovery,” the report said.
“Such actions will complement and greatly increase the effectiveness of local management actions in the Reef and its catchment.”
Today’s report is the third issued by the agency, which has tracked the continuing deterioration of the reef since 2009 – largely studying the area of coral killed or damaged by bleaching.
The report said the threats to wildlife, which include the future of the star-of-thorns starfish which prey on coral, are “multiple, cumulative and increasing.”
Authority chairman Ian Poiner said: “The accumulation of impacts, through time and over an increasing area, is reducing its ability to recover from disturbances, with implications for reef-dependent communities and industries.
“The overall outlook for the Great Barrier Reef is very poor.”
A study of coral bleaching on the reef, published in the journal Nature in 2017, found 91% of the coral reef had been bleached at least once during three bleaching events of the past two decades, the most serious event occurring in 2016.
A fourth major bleaching struck later in 2017 after the Nature study was published.
The United Nations World Heritage Committee expressed concern about bleaching in 2017 and the latest report could lead to the World Heritage-listed site being reclassified by Unesco next year as ‘in danger’.
Although the Great Barrier Reef has become internationally known as the world’s largest coral system, it is not the only reef under stress from rising ocean temperatures.
Australian environment minister Sussan Ley said she was unsurprised by the downgrade in the reef’s condition following years of damage inflicted by recent cyclones and bleaching events.
She said the government is ‘building resilience in this important global reef’ and is keeping its Paris commitment to reduce Australia’s greenhouse gas emissions by 26% to 28% below 2005 levels by 2030.
“I want to make the point that it’s the best managed reef in the world,” she said.