02/04/2020

Climate Crisis May Have Pushed World's Tropical Coral Reefs To Tipping Point Of 'Near-Annual' Bleaching

The Guardian - 

Exclusive: Mass bleaching seen along Great Barrier Reef could mark start of global-scale event, expert warns

Coral bleaching on the Great Barrier Reef in Australia. Sea temperatures over the reef were the highest on record this February. There are fears the world’s tropical coral reefs may have reached a tipping point of bleaching nearly every year. Photograph: Nature Picture Library/Alamy Stock Photo

Rising ocean temperatures could have pushed the world’s tropical coral reefs over a tipping point where they are hit by bleaching on a “near-annual” basis, according to the head of a US government agency program that monitors the globe’s coral reefs.

Dr Mark Eakin, coordinator of Coral Reef Watch at the National Oceanic and Atmospheric Administration, told Guardian Australia there was a risk that mass bleaching seen along the length of the Great Barrier Reef in 2020 could mark the start of another global-scale bleaching event.

Tropical coral reefs tend to be at a higher risk of bleaching during times when the Pacific Ocean is in a phase known as El Niño. The latest bleaching on the reef has hit during this cycle’s neutral phase.

“The real concern is with this much bleaching without tropical forcing,” Eakin said. “This may be a sign we’ve now tipped over to near-annual bleaching in many locations.”

“It’s quite concerning that we are getting this much heat stress across the Great Barrier Reef in an Enso [El Niño southern oscillation]-neutral year.

“What we are seeing on the Great Barrier Reef and potentially elsewhere is really being driven just by anthropogenic climate change.

“If we get another El Niño, the odds are almost 100% that we will see another global bleaching event.”

Aerial surveys of 1,020 individual reefs completed across the length of the 2,300km marine park confirmed last week a third mass bleaching event in only five years.

“That’s already pushing awfully close to near-annual bleaching,” added Eakin.
Corals bleach when they sit in abnormally hot water for too long. Reefs and corals can recover from mild bleaching, but severe and prolonged heat stress can kill corals.

In back-to-back bleaching in 2016 and 2017, about half the reef’s corals died.

Eakin said that in January Coral Reef Watch’s models were warning that heat stress would build across the reef in February and March. Sea temperatures over the Great Barrier Reef were the highest on record this February.

Satellite data later confirmed the modelling results which, Eakin said, was received “with a sense of dread” among scientists.

“I was not ready to have another bleaching event this quickly,” he said.

Eakin said the agency’s modelling for the next four months was showing a “classic pattern of heat stress” that had preceded previous global bleaching events.

Heat was predicted to rise first in the southern Indian Ocean, then to south-east Asia and into the Coral Triangle.

He said it was “too early” to say if a global bleaching event was on the way, but “it would not really surprise me”.

Eakin said that when severe bleaching causes mass mortality of corals, “those events take a decade or more for recovery. We are seeing these events far too frequently”.

As the planet gains heat from increased greenhouse gases in the atmosphere, about 90% of that extra heat is taken up by oceans. In January, a study of heat down to 2km in depth concluded that 2019 was the warmest year on record.

Eakin said ocean heat content data showed the world’s oceans were gaining heat. “There’s so much heat that has been absorbed in the upper ocean that all the coral reefs are much closer now to their bleaching threshold. As result, it’s very easy to tip them over.”

Data from nine days of aerial surveys over the Great Barrier Reef, carried out in mid-March, are being analysed and compiled at the ARC Centre of Excellence for Coral Reef Studies at James Cook University.

Dr Neal Cantin, a senior coral biologist at the Australian Institute of Marine Science, said because of the warming of the oceans caused by climate change, “we are already committed to more frequent and more severe bleaching in the next decade”.

Cantin said the Australian Institute of Marine Science would be carrying out monitoring of sites in the coming months to see which corals had survived this event and how 2020 had impacted recovery from previous bleaching.

“We need to understand the full extent of significant mortality,” he said.

Many areas of the Great Barrier Reef are known to have experienced severe bleaching this summer, likely killing many corals, but others, including tourist reefs near Cairns and the Whitsundays, only experienced mild bleaching. Most offshore reefs in the far north escaped bleaching entirely.

Scientists fear images of heat-stressed, bleached coral at Lizard Island on the Great Barrier Reef taken in February could be the start of another mass bleaching event. Photograph: Dr Lyle Vail, Director of the Australian Museum’s Lizard Island Research Station

“With mild bleaching, the animal survives but growth is slowed and they become more susceptible to disease,” said Associate Prof Tracy Ainsworth at the University of New South Wales.

She said mild bleaching can also impact the ability of the corals to spawn which can slow recovery from impacts.

“We have known for 20 years that probably by about 2020, we would start to see annual bleaching.”

Eakin added: “Even if the corals don’t die, bleached corals are injured and starving and they are more susceptible to disease. They will also reduce their reproductive output in a bleaching year and the year after.”

A 2019 study found bleaching in 2016 and 2017 had caused the numbers of new baby corals produced in 2018 to crash by 89%.

Cantin said that unlike in 2016 and 2017, the bleaching in 2020 appeared to have covered “the entire system” of the Great Barrier Reef.

Corals have a symbiotic relationship with algae that delivers nutrients and colour to the animal.

“Completely white coral means it has lost probably 95-100% of their symbiont algae and they will struggle to recover,” Cantin said.

“With moderate-level bleaching you will see the tips go white with some sections still having pigmentation left – they do have a good chance of surviving,” he said.

The Great Barrier Reef’s values as a world heritage-listed location are due for review at a meeting scheduled in China in June. Unesco has said that meeting is under review due to the Covid-19 pandemic.

In December 2019, Australia submitted a report to the committee that conceded climate change had impacted the reef’s values as a world heritage site since it was first listed in 1981.

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'Very Un-Antarctic': When The Icy Continent Was Not Very Cold At All

Sydney Morning Herald - Peter Hannam

Temperatures soared over much of Antarctica this past summer, prompting researchers to declare the first heatwave ever recorded at Australia's Casey station.

While the Antarctic Peninsula is well known to be among the fastest warming regions of the planet because of climate change, the continent's east had been relatively sheltered from the global heating.

Antarctic heatwave. Antarctica’s plants and animals depend largely on melting snow and ice for their water supply. Picture: Sharon Robinson/UOW

In a paper published on Tuesday in Global Change Biology, scientists from the University of Wollongong (UOW), Australian Antarctic Division, University of Tasmania and University of Santiago, Chile, identified periods of very unusual warmth that affected Antarctica’s ecosystems.

While record Antarctic heat in February made headlines around the world, the first signs of the heatwave actually appeared in the east of the continent several weeks earlier.

Over the 23-26 January period, "Casey experienced minimum temperatures above zero and maximum temperatures above 7.5 degrees, with its highest maximum temperature ever, 9.2 degrees on 24 January, followed by its highest minimum of 2.5 degrees the following morning", Sharon Robinson, a UOW climate change biologist, said.

“In the 31-year record for Casey, this maximum is 6.9 degrees higher than the mean maximum temperature for the station, while the minimum is 0.2 degrees higher.”

Professor Robinson said Chilean counterparts studying the moss of King George Island also registered the spike in temperatures. While a typical December-February period, such as a year earlier, would see the mercury rising above 14 degrees for 3 per cent of the year, this past summer saw that proportion there jump to 14 per cent.

A tide gauge is deployed in an ice hole at Casey research station, the site of an Antarctic "heatwave" earlier this year. Credit:Imojen Pearce/AAD

Those readings were "not very Antarctic", she said, adding that for areas where the temperature usually remained below zero, "it's very worrying" since many plants such as mosses and animals have adapted to the normally frigid conditions.

The heatwave definition was based on a similar measure used in Australia of three days and nights of temperatures in the top 10 per cent of readings for that date.

The success of global efforts to reduced ozone-depleting chlorofluorocarbon chemicals (CFCs) was one of the reasons for this summer's exceptional warmth along with the background climate warming.

As the ozone hole over Antarctica has closed, the strong westerly winds have abated, allowing the rising temperatures to reach regions - such as Casey station - that had previously been shielded, Professor Robinson said.

The past summer's heatwave "is probably a harbinger of the future, as we have stopped production of CFCs", she said. "A lot people think of Antarctic as pristine and protected but climate change gets everywhere, so it's not protected."

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(US) Trump To Roll Back Obama-Era Clean Car Rules In Huge Blow To Climate Fight

The Guardian -

▶Announcement will allow vehicles to emit 1bn more tons of CO2
▶Experts say move will lead to more life-threatening air pollution

Motor vehicles drive on the 101 freeway in Los Angeles, California. Critics say the move will lead to more life-threatening air pollution and force Americans to spend more on gasoline. Photograph: Robyn Beck/AFP/Getty Images

The Trump administration is rolling back the US government’s strongest attempt to combat the climate crisis, weakening rules which compel auto companies to produce more fuel-efficient vehicles. Critics say the move will lead to more life-threatening air pollution and force Americans to spend more on gasoline.

The changes to Obama-era regulations will allow vehicles to emit about a billion more tons of heat-trapping carbon dioxide – equivalent to roughly a fifth of annual US emissions.

The rollback is one of dozens Trump officials have ushered to completion, seeking to bolster the fossil fuel industry amid intense opposition from Democratic-led states and pushback from world leaders.

Experts say the world is far off track in dealing with the climate emergency, following a year of record-breaking heat, rising hunger, displacement and loss of life due to extreme temperatures and weather disasters.

Donald Trump is expected to laud the new rule as a boost to the US economy, which has been hit by the coronavirus pandemic. His administration says weakening the standards will make cars about $1,000 cheaper, leading Americans to buy new and safer models more frequently and resulting in fewer crash fatalities.
"Coronavirus preys on people with respiratory problems, and this dirty air rule will make more Americans vulnerable"
Miles Keogh, NACAA
The Environmental Protection Agency (EPA) chief, Andrew Wheeler, said in a statement: “Now, more than ever, this country needs a sensible national program that strikes the right regulatory balance for the environment, the auto industry, the economy, safety, and American families.

“[This rule] does all of those things by improving fuel economy, continuing to reduce air pollution, and making new vehicles more affordable for all Americans.”

Researchers dispute such logic.

Miles Keogh, executive director of the National Association of Clean Air Agencies, an organization of state and local air regulators, called the timing of the rule change “appalling”.

He said: “We know coronavirus preys on people with respiratory problems, and this dirty air rule will make more Americans vulnerable.”

The Obama administration required auto companies to make vehicles 4.7% more efficient each year. The Trump administration initially wanted to freeze any progress on fuel efficiency past 2020. But its final rule, written by the EPA and the Department of Transportation, sets an improvement rate of 1.5% per year – or an industry average of 40.4 miles per gallon by 2026.

That’s far less than the 2.4% per year by which the industry has said it will increase standards without any regulation.

The rollback has drawn opposition from nearly half of states and a significant portion of the auto industry. Twenty-three states and the District of Columbia, representing about half of US residents, sued over the changes. They said weakening the standards would kill about 2,000 more people and cause 50,000 more cases of respiratory illnesses, while making the climate crisis worse.

California has long instituted more stringent auto standards than the federal government, but the Trump administration has revoked the state’s authority to do so. The state last year struck a deal with four companies – Ford, Honda, Volkswagen and BMW of North America – to exceed what Trump is asking for and require cars, trucks and SUVs to get nearly 50 miles per gallon on average by 2026.

Democratic-run states and environmental advocates are expected to challenge the new regulation. They are already fighting the Trump administration over its weakening of dozens of other environment and public health protections.

Ann Carlson, a professor at the University of California in Los Angeles, said the legal fight will be “one of the hardest fought, in part because it’s the most significant”.

Carlson believes the rollback is meant to maintain demand for gasoline, which is expected to fall as vehicles become more efficient and transition to electricity.

“You can make cars with zero emissions now, zero greenhouse gases that don’t run on petroleum, any more,” Carlson said. “So I think the big beneficiaries are absolutely the oil companies.”

The rule change comes as many communities around the US are seeing a decline in air quality, a result of climate change, wildfires, higher temperatures, regulatory rollbacks and poor enforcement of regulations, said Paul Billings, senior vice-president of advocacy for the American Lung Association.

“This will mean there will be more pollution associated with oil extraction, transport, refining – sort of all the way from the well to the pump,” Billings said. “This will mean high levels of smog, more coughing, wheezing, shortness of breath, asthma attacks, COPD (chronic obstructive pulmonary disease) exacerbations and also more particulate pollution.”

The effects will be worse on communities near oil processing facilities and highways, often people of color and poorer Americans.

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