(AU SMH) No Climate Change Refuge For Coral Reefs: Study

Sydney Morning Herald - Miki Perkins

Global warming of 1.5 degrees above pre-industrial levels will be catastrophic for almost all coral reefs, including those that scientists once hoped would act as refuges during climate change.

Only 0.2 per cent of coral reefs globally are likely to avoid frequent heat stress if temperatures warm, according to new research from an international team of universities, including James Cook University in Townsville.

James Cook University marine biologist Jodie Rummer at work on the Great Barrier Reef. She has witnessed previous bleaching and described it as “scary and disturbing”. Credit: Grumpy Turtle

This finding comes as the Great Barrier Reef is on the cusp of another mass coral bleaching event because of record-breaking ocean temperatures, with reports that scattered areas of coral off Townsville and Mackay are already showing signs of heat stress.

This is alarming because the potential bleaching would be occurring during a La Nina weather event, which traditionally brings cooler and cloudier weather, but reef temperatures are some of the warmest ever recorded.

Associate Professor Scott Heron, one of the study authors from James Cook University, said scientists used cutting-edge climate modelling to predict how much thermal exposure shallow-water coral reefs would experience around the globe.

Even thermal refuges, which experts assumed would be more able to endure warming oceans owing to factors such as the consistent upwelling of cool deep waters, would provide almost no protection to reef animals, the study found. It is published today in PLOS Climate.

The effects of bleaching on the Great Barrier Reef were clear near Heron Island in 2016. Credit: Eddie Jim

Dr Heron said “this means corals worldwide are at even greater risk from climate change than previously thought, especially as limiting warming to 1.5 degrees is looking increasingly unlikely”.

In the three months leading up to mid-December, heat stress at the Great Barrier Reef reached record levels.

Great Barrier Marine Park Authority chief scientist David Wachenfeld said “we are now two-thirds of the way through summer, there’s a quite reasonable accumulation of heat stress out there and the next four weeks are absolutely critical”.

“The weather that we see will very strongly influence the outcome of the reef.”


The PM has pledged another $1 billion in a bid to help save the Great Barrier Reef. 

Ocean temperatures for most of the reef have been between 0.5 degrees and 1.5 degrees higher on average since the beginning of summer in most places, most of the time, he said.

While cyclones Seth and Tiffany and recent monsoonal rain did have some cooling effect, this hasn’t brought the reef back to average temperatures

There have been reports of minor coral bleaching in a range of places such as Cooktown, Townsville and Mackay that demonstrates the coral is showing early signs of stress, Dr Wachenfeld said.

“The thing that worries me when there is a severe impact to the Great Barrier Reef [is that] I always worry that people lose hope,” he said. “What the reef needs right now is the strongest possible action globally to reduce greenhouse gas emissions, with the strongest action to protect it locally.”

Last week the federal government promised to spend $1 billion on the reef over nine years, pledging new money for new technology, water management and coral seeding.

Reef experts welcomed the additional funding, but said it would do nothing to save the reef from the existential threat of climate change

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The Bureau of Meteorology says that December 2021 was, on average, the warmest December for the Great Barrier Reef since records began in 1900.

Above-median rainfall is predicted for much of February at Cape York and the Great Barrier Reef, and the extent of wind, cloud and rain will influence ocean temperatures.

Associate Professor Jodie Rummer witnessed coral bleaching in 2016 when the James Cook University reef expert was working on a project on the effects of climate change on reef fish at the Lizard Island research station, off Cooktown.

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The water temperature was two or three degrees higher than normal, similar to the temperatures she was simulating in the laboratory to reflect what was expected in the middle of this century.

“It was scary and disturbing,” Dr Rummer said. “I grew up with these dreams of wanting to make my contribution to science and conservation … and to see this happening before my eyes in my lifetime has been really, really upsetting.”

The reef is an internationally significant tourist destination, which supports 64,000 jobs and contributes $6.4 billion annually to the economy.

It suffered severe back-to-back bleaching that wiped out swathes of corals in 2016, 2017 and 2020.

Links

• (AU The Guardian) Great Barrier Reef On Verge Of Another Mass Bleaching After Highest Temperatures On Record
• (AU ABC) Coral Reef Safe Zones Set To Plummet, While Potential Bleaching Events Loom In Qld, WA
• (AU ABC) $1b Plan To Save Great Barrier Reef Will Fail Without Climate Change Action, Expert Says
• Let's strip away the politics and look at the facts — the things that actually matter to the reef
• Morrison government announces $1bn pledge for Great Barrier Reef over the next decade
• Great Barrier Reef: Australia must act urgently on water quality, says Unesco
• Australia must choose between coal and coral – the Great Barrier Reef depends on it
• Great Barrier Reef authority a 'shell of its former self', says Queensland minister

(AU ABC) Coral Reef Safe Zones Set To Plummet, While Potential Bleaching Events Loom In Qld, WA

ABC Science | Nick Kilvert

Ningaloo Reef in Western Australia is still fairly intact, but is expected to bleach in future. (Getty Images: Richard Lock)

Key Points Researchers predict just 0.2 per cent of the world's reefs will be unaffected by warming at 1.5C Signs suggest bleaching events may occur in WA and QLD in the coming weeks Climate action is the only thing that can really improve the outcome for coral reefs

The number of coral reefs worldwide that will be spared the harm of warming is predicted to plummet within just a few decades.

That's the finding of research published today in the journal PLOS Climate, which comes as reef scientists "anxiously" eye off the potential for bleaching events on the Great Barrier Reef and in Western Australia over the coming weeks.

Currently about 84 per cent of the world's coral reefs are buffered from ocean warming by influences like cool upwellings, deep water, and cooler ocean currents.

But today's research shows that figure will drop to just 0.2 per cent of reefs when global warming breaches 1.5 degrees Celsius above pre-industrial levels.

We're currently forecast to hit 1.5C in the 2030s, and it's believed that there's now almost no chance of staying under that limit without extremely aggressive cuts to emissions and unproven carbon capture technologies that can draw CO2 from the atmosphere.

The Great Barrier Reef suffered bleaching events in 2016, 2017, and 2020, and the co-author of today's paper, Scott Heron from James Cook University, said scientists were anxiously watching weather patterns in Queensland's north, and off the northern WA coast.

Scientists are anxiously watching conditions in the Great Barrier Reef. (Getty Images: Brett Monroe Garner)

"Here we are at the end of January — summertime in Australia — and we're seeing heat stress developing to a point of potential widespread coral stress on the Great Barrier Reef," Dr Heron said.

"We're at a point of social anxiety among the coral reef community, wondering what the next month may hold."

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Some overcast monsoonal weather has given the reef a brief reprieve from the heat, and scientists are hoping for more of the same to stave off yet another catastrophic hit just two years after the last, Dr Heron said.

But there are already signs of corals fluorescing — a sign of distress in some species — and some whiteness has been observed, according to marine biologist Jodie Rummer from JCU.

She says temperatures are already high and if there are cumulative days of heating over the next weeks or months, bleaching is likely to occur.

"We've got temperatures that are warmer than expected [and] there's not as much mixing [of water] as we'd hoped, despite it being a La Nina," Dr Rummer said.

Marine biologist Mike van Keulen from Murdoch University in Perth says there are already "signs of coral stress" in north-west Western Australia as well.

Warm waters in the north can cause coral stress down much of the WA coastline, Dr van Keulen says.

"Particularly for WA, that becomes a problem because the warm water to the north of us seeds the Leeuwin current that runs down our coast.

"The last big event we had in 2011 bleached corals all the way down to Rottnest Island [off Perth]."

At 2C, no reef will be spared

In order to understand the future of coral reefs globally, Dr Heron and colleagues from the University of Leeds and Texas Tech University modelled the impact of warming on reefs down to a resolution of 1 square kilometre.

At 1.5C of warming, they found only a few reefs in Polynesia and the Coral Triangle in the western Pacific would be spared recurring "thermal stress events" at least once every 10 years, according to Dr Heron.

"There were very few places around the world [that would be spared] and they were focused in the area of French Polynesia and the Coral Triangle," he said.

Many of the more delicate and colourful corals will disappear as we head towards 1.5C of warming. (Getty Images: Colin Baker)

The scientists found that more than 90 per cent of reefs will suffer these thermal stress events at least every five years.

Thermal stress events are periods of elevated sea-surface temperature capable of causing "significant coral bleaching".

No reefs in Australia will be immune to regular thermal stress events once warming reaches 1.5C, they concluded.

At 2C of warming, no reefs worldwide will be spared the impact of climate change.

Today's findings, and the prospect of yet another bleaching event, underline how important climate action is for the reef, Dr Rummer said.

"All of these secondary and tertiary issues the reef is facing, it's not going to matter if we fix them without addressing the real problem, which is climate change," she said.

A number of scientists, including Dr Rummer, were critical of last week's pledge by the federal government for $1 billion over nine years for the reef, without also committing to ambitious climate action.

Dr van Keulen says programs that will be funded under the government's pledge, which are aimed at improving the resilience of corals, are "too little, too late".

"We've got climate change that causes consecutive years of bleaching; there's no way we can return to normal from here.

"The only chance we can make a difference is to rapidly wind back emissions."

As we approach 1.5C, Dr van Keulen says the delicate, colourful corals we associate with tropical holidays will be gone.

As they go, we will see "huge flow-on effects" in fish abundance and diversity, which will also impact many commercial industries like seafood and tourism.

Dr Heron says the more we study the impacts of climate change on reefs, the more we realise we're heading toward a "cliff face".

Links

• $1b plan to save Great Barrier Reef will fail without action on climate change, scientist says
• Great Barrier Reef 'seen from outer space, not an office in Paris', says Minister rebuking UNESCO's warning
• First it was the reef, now the seagrass beds feeding our dugongs are sounding the climate change alarm
• (AU The Guardian) Great Barrier Reef On Verge Of Another Mass Bleaching After Highest Temperatures On Record
• (AU ABC) Coral Reef Safe Zones Set To Plummet, While Potential Bleaching Events Loom In Qld, WA
• Let's strip away the politics and look at the facts — the things that actually matter to the reef
• Morrison government announces $1bn pledge for Great Barrier Reef over the next decade
• Great Barrier Reef: Australia must act urgently on water quality, says Unesco
• Australia must choose between coal and coral – the Great Barrier Reef depends on it
• Great Barrier Reef authority a 'shell of its former self', says Queensland minister

(Reuters) Penguins Offer Varied Clues To Antarctic Climate Change

Reuters - Gloria Dickie | Natalie Thomas

Adelie penguins stand together as scientists investigate the impact of climate change on Antarctica's penguin colonies, on the eastern side of the Antarctic peninsula, Antarctica January 17, 2022. REUTERS/Natalie Thomas

Summary Penguin species are a key indicator for environmental change Gentoo penguins are moving down warmer Antarctic Peninsula Expedition finds Adelie colonies are stable in Weddell Sea

ABOARD THE MV ARCTIC SUNRISE, Antarctica - Peering through binoculars from an inflatable motorboat bobbing in frigid waters, polar ecology researchers Michael Wethington and Alex Borowicz scan a rocky outcrop on Antarctica's Andersson Island for splatterings of red-brown guano that might signal a colony of penguins nearby.

The birds have become far more than an iconic symbol of the earth’s frozen south.

Scientists now use them as key indicators for understanding climate change near the South Pole – with certain western regions like the Antarctic Peninsula having undergone rapid warming, while East Antarctica remains cold and capped in ice.

"We are counting penguin nests to understand how many penguins are in a colony, producing chicks every year, and whether that number is going up or down with the environmental conditions," said Borowicz, of Stony Brook University in New York.

For climate researchers, nothing is easy in the remote and icy reaches of Antarctica. But penguins are easier to track than other species because they nest on land and their black feathers and their waste can be spotted against the white expanse.

"We can use penguins as a bioindicator to see how the rest of the ecosystem is operating," said Wethington, also of Stony Brook.

Scientists work near Adelie penguins while investigating the impact of climate change on Antarctica's penguin colonies, on the eastern side of the Antarctic peninsula, Antarctica January 16, 2022. REUTERS/Natalie Thomas

Simple counts of individual penguins alongside other methods like analyses of satellite images tell a nuanced story, with some penguins dubbed 'winners' as climate change opens new habitats, while others are forced to seek colder climes.

WAVE OF 'GENTOOFICATION'

Gentoo penguins, with bright red-orange beaks and distinctive white markings on their heads, are partial to open water without chunks of ice bobbing around.

When temperatures on the Antarctic Peninsula began rising faster than almost anywhere else in the world during the latter half of the 20th century, gentoo populations expanded southwards in what some scientists call the "gentoofication" of Antarctica.

"Gentoo penguins don't like sea ice," said David Ainley, a biologist with the ecological consulting firm H.T. Harvey & Associates who has been studying penguins for more than 50 years. “They mostly forage over the continental shelf and don’t go far out to sea.”

As sea ice has decreased along the western side of the peninsula, gentoos have taken advantage of the hospitable conditions. But the same conditions have been worse for tuxedo-wearing Adelies, who rely on sea ice for breeding and feeding.

"When we find Adelie penguins, we typically know that sea ice is nearby," Wethington said. "And whenever we've seen sea ice declining or disappearing altogether, then we're seeing corresponding Adelie penguin populations decline substantially."

Though widespread Adelie penguins are increasing in number overall, some populations have fallen by more than 65 percent.

'SAFE SPACE'

On their January expedition to the region, the Stony Brook scientists found that Adelie colonies around the still-icy Weddell Sea had remained stable during the past decade.

"This peninsula is maybe a safe space as we see climate change progressing and overall warming throughout the globe," Wethington said.

Penguins are seen on a rock as scientists investigate the impact of climate change on Antarctica's penguin colonies, on the eastern side of the Antarctic peninsula, Antarctica January 16, 2022. REUTERS/Natalie Thomas

Heather Lynch, an ecologist at Stony Brook University who helped lead the expedition aboard the MV Arctic Sunrise, said the findings highlighted the region's conservation value.

In 2020, a team from the British Antarctic Survey discovered 11 new emperor penguin colonies from satellite images, boosting known emperor penguin colonies by 20 percent.

But since 2016 nearly every chick has perished in the Halley Bay colony along the far eastern side of the Weddell Sea, which has long been home to the world's second largest emperor penguin colony, with some 25,000 breeding pairs gathering every year.

Penguins swim in the sea as scientists investigate the impact of climate change on Antarctica's penguin colonies, on the northern side of the Antarctic peninsula, Antarctica January 15, 2022. REUTERS/Natalie Thomas

Scientists suspect the 2016 El Niño event changed the sea ice dynamic in the area, and worry for the penguins as climate change increases the frequency and severity of El Niño events.

While the chicks' deaths were not a direct result of climate change, "there is a climate change aspect to the loss," said Peter Fretwell, a geographic information scientist at the British Antarctic Survey.

Links

• Here's how scientists use Penguins to predict climate change
• (Video YouTube) Penguins help understand climate change, here's how!
• As climate change melts Antarctic ice, gentoo penguins venture further south
• 98% of emperor penguin colonies could be extinct by 2100 as ice melts – can Endangered Species Act protection save them?
• Penguins are moving into new areas of Antarctica as climate change makes them habitable
• Virtually all emperor penguin colonies doomed for extinction by 2100 as climate change looms, study finds