For the first time, the long-term outlook for the Great Barrier Reef has been downgraded to "very poor" by the Federal Government, with the impacts of climate change deteriorating its overall health.

Key points: The report said global and national action on climate action "within the next 10 years" was imperative for reef's future survival

The report said global and national action on climate action "within the next 10 years" was imperative for reef's future survival Without additional action on climate change, the ecosystem will remain very poor

Without additional action on climate change, the ecosystem will remain very poor The findings could have consequences for the Great Barrier Reef's UNESCO World Heritage listing

The evidence-based report written by the Great Barrier Reef Marine Park Authority (GBRMPA) using more than 1,000 scientific reports, was described by its chairman Ian Poiner as "sobering findings".

The five-yearly report said climate change is escalating and is the most significant threat to the Great Barrier Reef's long-term survival.

"The current rate of global warming will not allow the maintenance of a healthy reef for future generations," the report said.

Experts said strong mitigation actions "within the next decade" are necessary.

"Specifically, early and effective global and national action on climate change, coupled with local actions to … facilitate recovery, are imperative over the next 10 years if the region is to have a positive long-term outlook.

According to the report, without additional action, "the overall outlook for the Great Barrier Reef's ecosystem will remain very poor, with continuing consequences for its heritage values also".

"The challenge is big, but not insurmountable — actions taken now will matter."

The downgraded outlook status comes after back-to-back coral bleaching events, cyclones and record-breaking warm water — particularly affecting the northern part of the reef, which had previously been considered to be pristine.

Mr Poiner said the decline was despite "recent management initiatives to reduce threats and improve reef resilience".

Experts said the decline will continue unless there is urgent and coordinated action to curb greenhouse gas emissions.

The findings come on the same day the Federal Government released its quarterly emissions data for the first three months of 2019. It shows that pollution for the year to March rose by 0.6 per cent.

Australian emissions have risen for five years in a row.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 1 minute 8 seconds 1 m 8 s The chair of the Great Barrier Reef Marine Park Authority said the report was "sobering".

The report found there is a "multi-tiered governance and management regime" to protect the reef, but "it is not designed to directly address the effects of a changing climate."

Environment Minister Sussan Ley said it was "unsurprising" the condition had deteriorated.

She said steps were already being taken to address the challenges, including the launch of a $6 million "Reef Resilience" vessel.

"This is an outlook we can change and are committed to changing," she said.

"It might take time to see these strategies translate into tangible outcomes, as in the case of humpback whale and southern green turtle populations, which continue to increase."

Ms Ley said the reef is the "best managed reef in the world" and reiterated the Government's $1.2 billion funding commitment.

"We are taking the action that we're required to do under our Paris [climate change] agreements," she said.

She pointed to the various interventions being undertaken into water quality, sustainable fishing, and controlling the crown-of-thorns starfish while commending Indigenous land managers and farmers who are working to prevent sediment run-off into the reef.

Ms Ley said another bleaching event soon will see the reef deteriorate further.

Coral bleaching and cyclones caused significant harm

Sea temperature extremes caused successive mass bleaching events in 2016 and 2017, which led to unprecedented and widespread coral loss and flow on effects to fish and invertebrate communities.

According to the report, 50 per cent of the reef has been exposed to destructive waves from six tropical cyclones since 2014.

As an example, six reefs were surveyed following Cyclone Debbie in 2017.

The reef off Lizard Island is experiencing 'total ecosystem collapse' according to researchers. ( Supplied, Kay Davis )

They showed an average of 70 per cent loss of coral cover at two metres, and 64 per cent loss at depths of five metres.

In some areas, the loss was as high as 98 per cent.

Impacts on tourism and World Heritage listing

The report said while the reef's value as a World Heritage Area remained "intact", its integrity is now "deteriorating".

"Human-induced climate change is challenging the integrity of the World Heritage Area, its size is becoming a less effective buffer against broadscale impacts," the report said.

A condensed version of the report will be provided to the United Nations in December, so it can determine if the reef's health has improved enough since 2014 in order to retain its cultural heritage status.

Richard Leck from World Wild Fund for Nature said UNESCO considered placing the Great Barrier Reef on the World Heritage 'In Danger' list in 2015, but they did not because the Government promised to improve the condition of the reef.

"These reports show that hasn't happened, in fact the condition and the outlook has got worse. Surely that's got to be ringing alarm bells," he said.

The Federal Government said 64,000 Australians depend on the $6.4 billion reef economy.

The research notes the deterioration will have social and economic implications for regional communities, because commercial marine tourism and fishing depend heavily on the reef.

"As reef waters continue to heat, coral reefs will become less diverse than a decade ago, and the fishes seen while snorkelling and caught while fishing, will also change," the report said.

"Reef-dependent users need to prepare for this change."

Despite the poor outlook, GBRMPA CEO Josh Thomas said the GBR remains "beautiful and healthy" in large areas.

Reduction of 'pollutant loads' has been too slow

Poor water quality continues to affect many inshore areas of the reef, with researchers noting that improvement targets have not been met.

The report also found reduction of pollutant loads has been slow, reflecting modest improvements in agricultural land management practices.

The Federal and Queensland Governments have also released the Reef Report Card for 2017-2018.

It shows that while improvements have been made to land management practices, more work is urgently needed.

Governments have set a target to have 90 per cent of affected grazing and sugarcane land covered by best-practice management systems by 2025.

However, both industries have scored poorly overall, with just 35.8 per cent of grazing land and 9.8 per cent of sugar regions meeting that target.

Ms Ley said farmers were doing their part.

"Under our actions around water quality, we have reduced sediment run-off into the reef by 5,400 tonnes," she said.

"If you take the Burdekin catchment that provides most of the sediment, we're seeing a reduction of 47 per cent

Queensland Canegrowers CEO Dan Galligan said the Report Card was "unhelpful and inaccurate" and suggests the 'goalposts' have shifted since the 2016 report.

"It underestimates what is actually happening, by not including in its calculations any changes in farm practices prior to 2016," he said.

"I think farmers across the state are taking responsibility where they can, and they've got to do their bit on their farms and that's what we're seeing.

"They [GBRMPA] point to the fact that all that investment by farmers is a waste of time unless governments come together on a clear policy on climate change," he said.

A director of the Australian Marine Conservation Society, Imogen Zethoven, said the reports were concerning.

"The Queensland Government has a bill in Parliament to help reduce land-based run-off. It needs to be passed and implemented as soon as possible. Cleaner water gives the reef the resilience it needs," she said.

Crown-of-thorns starfish have devastated vast amounts of coral on the Great Barrier Reef. ( Flickr: Ryan McMinds )

Another serious threat to the Great Barrier Reef is from the coral-eating crown-of-thornes starfish (CoT), which can thrive on sediment run-off.

The reef is still experiencing an outbreak of the starfish, which began back in 2010 and continues to be graded as "very-poor".

The pests are difficult to manage and, coupled with coral bleaching, have led to a decline in coral cover.

Their impact is so severe that even if corals are not affected by any other disturbances, outbreaks can take at least 10 years to recover from.

In years to come, that recovery is expected to be further slowed by other stresses, including from climate change.