The Great Barrier Reef is facing 'catastrophic' risks – don't despair

The world's alarm bells are ringing loudly. What follows is a list of really good reasons to despair – and an excellent argument for why you absolutely should not.

The Great Barrier Reef, the shining jewel of Australia's natural beauty, is under "existential threat" from the climate crisis. The reef and others like it around the world have just blown past one huge climate stop sign and at this rate, the next, presumably fatal, milestone could be reached within 10 years.

All of this and more truly dire phrases — "worst for 400 years", "near-annual bleaching", "reef to rubble" — form part of a new report by dozens of experts warning of a new reality as the planet hits its first climate tipping point.

"Catastrophic conditions and dire reef ecosystem changes are no longer a threat on a distant horizon: It's happening now," James Cook University marine biologist Michael Kingsford is quoted as saying.

Your reaction probably falls into one of two camps: we're doomed or she'll be 'right. But there's a third, much more helpful path.

JCU marine biologist and conservation psychologist Dr Brock Bergseth argues now is the "time for alarm but it's also a time for action".

"The alarm bell is ringing," he tells 9news.com.au.

"You know, coral reefs are kind of the canary in the coal mine. They're singing right now, right? They're singing and they're telling us that there's dire things happening and we really need to wake up. 

"So to me, this is a great opportunity to really, kind of try to push that things are looking bad, but it's not, it's not guaranteed."

He says we could be on the verge of reaching a "social tipping point" beyond which individuals, businesses and governments are essentially forced to act.

It's happened before. Several whale species recovered from near extinction after the world decided their survival was more important than their blubber; Chlorofluorocarbons (CFCs) ripped a hole in the ozone layer for decades until the world had enough and banned them; green turtles, hunted to the brink of extinction for soup, eggs and pretty shells, were taken off the endangered list just this week.

"We are kind of on the verge of what many people would consider a change bigger than the industrial revolution," he said. 

"You think about how we as humans have already responded to change. 

" … So to me, like, when people care and when they're connected with meaningful actions that they can do, we can actually really deliver some significant and scalable conservation wins."

World risking systems collapse

There are even bigger impacts on the horizon to follow the carbon-emissions-driven severe heatwaves, floods, droughts and bushfires we're already seeing.

From the Amazon rainforest and reefs to polar ice sheets and ocean currents, climate change risks tipping earth's essential systems off balance and into collapse.

"We are rapidly approaching multiple Earth system tipping points that could transform our world, with devastating consequences for people and nature," report co-author Professor Tim Lenton said.

The report says warm-water corals such as the Great Barrier Reef and those found in the Caribbean, which are less diverse so less resilient, will be the first systems to go. 

Their estimated "tipping point" – 1.2 degrees of warming over pre-industrial levels – is already in the rearview mirror and the authors expect the upper estimate of their resilience – 1.5 degrees – to be passed within 10 years on current emissions trends.

"At the global level, rapid and stringent greenhouse gas mitigation is fundamental to return coral reefs back from the brink," they experts say, while recommending curbing acting on overfishing, curbing agricultural runoff, and regulating coastal development on a local scale.

"Unless we return to global mean surface temperatures of 1.2°C (and eventually to at least 1°C) as fast as possible, we will not retain warm-water reefs on our planet at any meaningful scale."

Great Barrier Reef under threat

The GBR could face "critical impacts", "catastrophic bleaching" and a phenomenon scientists call "reef to rubble", all of which are difficult if not impossible to recover from. 

Tourism to the reef alone is worth $9.2 billion a year. In the Coral Triangle fringing a host of countries immediately to Australia's north, it's estimated collapse could cause $115.4 billion in losses for tourism and fisheries alone.

"We have now pushed (coral reefs) beyond what they can cope with," said Mike Barrett, chief scientific advisor at the World Wildlife Fund UK and co-author of the report. 

The impacts will have far-reaching consequences. Coral reefs are an essential habitat for marine species, vital for food security, contribute trillions to the global economy and buffer coastal areas from storms.

If you care but don't know what to do, Bergseth has two key pieces of advice: pressure your local MP and vote with your wallet to support businesses actively combating climate change.

"We're in dire straits right now, but not all hope is lost," he says. 

"This is what you can do to make a difference today."

'This grim situation must be a wake-up call'

One of the tipping points scientists are most concerned about is the potential collapse of the Atlantic Meridional Overturning Circulation, a crucial network of ocean currents.

It would be catastrophic, pushing parts of the world into a deep freeze, heating up others, disrupting monsoon seasons and raising sea levels.

"There is now a risk that collapse could occur within the lifetime of people born and living on the planet today," Wildlife Fund UK chief scientific advisor and report co-author Mike Barrett said.

For Australia, the report says the collapse could make parts of inland and southern Australia even drier and make summers even wetter in the north.

That could actually boost food production in some areas but the unpredictability would make long-term planning hard.

The authors picked out one other positive, highlighting the "radical global acceleration" of solar power, electric vehicles, batteries and heat pumps, and noting polluting tech is unlikely to return once replaced because the cleaner options are cheaper and better.

Governments gather next month in Brazil for COP30, a particularly important edition of the annual United Nations climate conference because countries are supposed to ramp up their emissions-reduction goals.

"This grim situation must be a wake-up call that unless we act decisively now, we will also lose the Amazon rainforest, the ice sheets and vital ocean currents," Barrett said. 

"In that scenario, we would be looking at a truly catastrophic outcome for all humanity."

Prime Minister Anthony Albanese announced last month that the nation would aim to reduce total carbon emissions by 62 per cent to 70 per cent, compared to 2005 levels.

- Reported with CNN