Bleached coral, sapped of its once-brilliant colors, is seen on Australia's Great Barrier Reef.

(Australian Institute of Marine Science)

At a Glance

The Great Barrier Reef Marine Park Authority issued a six-page statement on climate change.The statement calls for swift international action to save the reef.Climate change has already had devastating effects on the World Heritage site.

The agency that manages Australia's Great Barrier reef is calling for the "strongest and fastest possible actions" to combat the impacts of climate change on the World Heritage site.

The Great Barrier Reef Marine Park Authority issued a six-page this week. In it, the authority asks both Australian and international bodies to set policies that will help protect the reef, including reducing global gas emissions, entering into partnerships and plans that reduce environmental damage to the reef and finding ways to restore parts of the reef already hit hard by climate change.

"Climate change is the greatest threat to the Great Barrier Reef," the statement said. "Only the strongest and fastest possible actions to decrease global greenhouse gas emissions will reduce the risks and limit the impacts of climate change on the reef. Further impacts can be minimised (sic) by limiting global temperature increase to the maximum extent possible and fast-tracking actions to build reef resilience."

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The climate change statement has been in the works for a year, but was just , the Guardian reported.

The statement cites back-to-back marine heat waves in 2016 and 2017 that caused and die-offs over two-thirds of the reef, which covers more than 238,000 square miles and is on the planet, according to UNESCO.

"Of particular concern are projections that the reef could be affected by bleaching events twice per decade by about 2035 and annually by about 2044 if greenhouse gas emissions continue to increase at the current rate," the authority said. "If bleaching becomes more frequent and more intense, there will not be enough time for reefs to recover and persist as coral-dominated systems in their current form."

Coral bleaching occurs when environmental stressors, such as too-warm water, cause corals , according to the Australian Marine Science Institute. The algae helps feed the coral through photosynthesis. Without it, the coral can die.

"Together with the impacts of 11 severe tropical cyclones since 2005, these events have caused an unprecedented decline in the health of the reef," the statement said.

Environmentalists supported the agency's assessment.

"The Great Barrier Reef is not dead yet, but the marine park authority makes it clear that it is already under stress from rising temperatures," Christian Slattery, a campaigner for the Australian Conservation Foundation, told the Guardian. "As the marine park authority states, any additional increase in temperatures will have further devastating impacts on the reef and flow-on effects for tourism, fishing, recreation and traditional use."

UNESCO, which granted World Heritage status to the reef in 1981, has considered taking steps toward downgrading its status due to water quality and other issues.

The marine park management authority said the reef attracts nearly 2 million visitors a year from across the globe and pumps billions of dollars annually into the Australian economy.

"Strong global action to curb climate change is needed urgently to give the Great Barrier Reef the best chance of survival," it said.