Lethal Heating: 04/14/20

14/04/2020

More Than Half Of Remote Reefs In Coral Sea Marine Park Suffered Extreme Bleaching

The Guardian - Graham Readfearn

Exclusive: researchers found some areas outside the bounds of the Great Barrier Reef had 90% of their shallow water corals bleached this summer

Coral Sea bleaching at Holmes Reef, about 220km east of Cairns. Extreme levels of bleaching such as this may lead to the death of many corals. Photograph: Dani Ceccarelli

More than half of the spectacular and remote coral reefs beyond the boundaries of the Great Barrier Reef suffered severe bleaching this summer, an underwater scientific expedition has found.
Several reefs in the vast Coral Sea marine park known among divers for their arrays of corals, large fish and precipitous drop offs into the deep ocean suffered extreme bleaching.

Scientists from James Cook University’s ARC Centre of Excellence for Coral Reef Studies recorded the bleaching on the reefs that are more than 200km offshore during dives in February and March.

Some reefs had 90% of their shallow water corals bleached – an extreme level likely to lead to deaths of many corals, said Prof Andrew Hoey, a co-ordinator of the expedition.

Hoey said: “It’s becoming too familiar to jump in to the water and see large swatches of severely bleached corals. It’s quite devastating.”

Even at 10 metres deep, some reefs saw half their corals bleached, with isolated bleaching seen as deep as 20 metres.

Hoey, a marine biologist at James Cook University, said the results were preliminary with further analysis to be carried out for the three-year monitoring project, which comes to a close in June.

The project is the most extensive reef survey of the Coral Sea Marine Park ever undertaken and is funded by the federal government agency Parks Australia.

Bleaching at Holmes Reef. Photograph: Dani Ceccarelli

Hoey said in 2020 they had visited “the majority of the reef complexes” across the marine park that covers almost 1m sq km. A small number of reefs in the far north and far east were not visited this year.

More than half of the reefs visited had been severely bleached, including dive tourism spots like Osprey Reef north of Port Douglas, Bougainville Reef off Cooktown and Flinders Reef off Townsville.

The Coral Sea reefs are less well known than their neighbours to the west on the Great Barrier Reef, which experienced a third mass bleaching outbreak in five years this summer.

The Coral Sea reefs were surveyed between mid-February and mid-March. Hoey said water temperatures were above 30C. Usual temperatures were 27C and 28C.

Corals bleach when they sit in unusually hot water for too long. Corals can recover if bleaching is only mild but if temperatures are very high for prolonged periods, corals can die.

On 18 March, the US government’s Coral Reef Watch program produced analysis of heat stress over the Great Barrier Reef and the Coral Sea showing “significant amounts of heat stress”.

Townsville-based Dr William Skirving, of Coral Reef Watch, told Guardian Australia: “All the Australia reefs outside of the GBR will have had significant amounts of bleaching and many would have had significant amounts of mortality.”

Hoey said unlike reefs closer to shore in the Great Barrier Reef Marine Park, the reefs in the Coral Sea were largely unaffected by pollution and fishing pressures.

“But they are extremely susceptible to climate-induced stresses,” he said.

Hoey said it was “hard to predict” how many corals would die.

These more remote reefs, he said, relied on their own corals to spawn and regrow, unlike the more tightly packed reefs of the Great Barrier Reef.

He said: “Any coral mortality will take a lot longer to recover from because there is hundreds of kilometres between these reefs and so there’s unlikely to be a lot of connectivity between them.”

“Because of their isolation we have a lot to learn about these reefs, but we would still expect any fish and other organisms relying on the reefs to have been affected, particularly those relying on the corals for food and shelter.”

Richard Leck, WWF-Australia’s head of oceans, said it was concerning that Coral Sea reefs had bleached because they were regarded as more resilient, as they benefitted from cool water upwelling and very clear water.

He said: “The fact they have bleached shows how extreme the underwater heatwave was in the Coral Sea. It shows how close we are to a tipping point with climate change and coral reefs.

“The reefs in the Coral Sea are less well known, except amongst the high-end scuba diving community. They’re a jewel in the crown for many divers around the world to come and visit.”

Craig Stephen, managing director of Mike Ball Dive Expeditions, has been visiting the Coral Sea reefs since 1995.

He said there were still many amazing places to visit on the Great Barrier Reef and the Coral Sea and “given time” he said he thought the reefs would recover.

“These [Coral Sea] reefs rise from the sheer depths in very clear water,” he said. “Large soft corals and sea fans dominate the depths and sharks abound, giving the diver a real sense of being in the abyss.

“You can hang off a wall that’s 1,000 metres and there you feel pretty insignificant. People enjoy the vastness of it.”

The 2020 bleaching was a “reset point for many of us” he said, adding: “We do need to step back and have a look at what we are doing to the planet.

“If we don’t take a good look at ourselves and do something about our CO2 emissions then things will get out of our control. There is a chance to do something about this.”

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Methane Levels Reach An All-Time High

Scientific American - Jeremy Deaton

New NOAA analysis highlights an alarming trend; experts call for curbing pollution from oil and gas wells

Credit: Richard Hamilton Smith Getty Images

A preliminary estimate from NOAA finds that levels of atmospheric methane, a potent heat-trapping gas, have hit an all-time high.

Methane is roughly 80 times more powerful than carbon dioxide, and while it stays in the atmosphere for only around a decade, as opposed to centuries, like CO₂, its continued rise poses a major challenge to international climate goals.

“Here we are. It’s 2020, and it’s not only not dropping. It’s not level. In fact, it’s one of the fastest growth rates we’ve seen in the last 20 years,” said Drew Shindell, a climate scientist at Duke University.

To gauge methane levels, scientists regularly gathered samples of air from dozens of sites around the world and analyzed them at NOAA’s Global Monitoring Laboratory in Boulder, Colorado. By comparing measurements, they were able to determine the global average. In 2019, the concentration of atmospheric methane reached nearly 1875 parts per billion, the highest level since record-keeping began in 1983.

Even more troubling, 2019 saw the second-largest single-year leap in two decades. However, this figure may change, as preliminary estimates have trended high, said Ed Dlugokencky, a research chemist at NOAA. The final numbers will likely be unveiled in November after a more detailed analysis.

“We’re still waiting to see what the final number is going to be, and it’s going to be many months before we know that,” Dlugokencky said. “But the fact that methane is increasing means it’s further contributing to climate change.”

Methane emissions primarily come from natural sources, like wetlands, and manmade sources, like farms and oil and gas wells. In wetlands, microbes excrete methane, an issue that humans can do little about. On farms, cows and sheep belch methane—a problem that people can address by raising fewer livestock.

“Eat less beef and less dairy. That’s the most straightforward thing,” Shindell said. “For the sake of our own health, we should be doing that anyway.”

The easiest way to stem methane pollution, however, is to limit its release from oil and gas drilling sites, he said. Natural gas is mostly methane, and it is prone to leaking from wells. There are essentially two ways to deal with this problem. The first is to burn the natural gas that seeps out, which turns the methane into carbon dioxide. The second is to plug the leaks.

Companies can install recovery equipment that allows them to collect the natural gas that would otherwise seep out. They can then sell this gas, helping to offset the cost of the equipment. By one estimate, oil and gas firms could cut methane pollution by 45 percent at no net cost.

Despite this, many companies are reluctant to pay for recovery equipment. Firms will instead spend their limited capital on a new drilling site, for instance, which will yield a greater return on investment, Shindell said, though practices vary.

Major players—including Chevron, Exxon Mobil, BP and Shell—are taking steps to cap methane pollution, in part, to shore up their public image. However, smaller firms operating on thinner profit margins have less incentive to invest in recovery equipment. And the coronavirus could make the problem worse, as companies facing declining revenues could pay less attention to leaks. For this reason, advocates have called for greater regulation of the oil and gas sector.

“I think that has taken on urgency because in recent years we have witnessed a surge in production of oil and natural gas,” said Devashree Saha, a policy analyst at the World Resources Institute. “Increasing the oversight and regulation of oil and gas production is the only way to go right now.”

Methane levels were more or less flat from the late 1990s to the early 2000s. They began to rise after 2006 thanks, at least in part, to more oil and gas drilling. Their recent uptick threatens the goals of the Paris Climate Agreement, as scientists had assumed that methane concentrations would stay level and then drop off when they projected how countries would meet their climate targets. Experts say that curbing methane emissions is needed to limit warming in the short term, buying humanity much needed time to adapt to climate change.

“You see the benefits in the first decade or two that you make cuts. You see fewer people dying from heat waves. You see less powerful storms and all of the stuff that comes from climate change,” Shindell said. “As long as we’re still using fossil fuels, we should at least not be leaking out lots and lots of methane.”

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Australian Forest Study May Challenge Climate Change Optimism

ABC Rural - David Claughton

As fires burned, researchers studied how much carbon mature trees could capture and store.
Supplied: University of Western Sydney

Key points

A landmark Australian study has been published by Nature
Study finds mature forests cannot store extra carbon if emissions go up
The finding could affect climate modelling assumptions

As Australia's forests burned earlier this year, people around the world worried about the impact of all that smoke on our climate.

At the same time, researchers in New South Wales were finalising a study looking at the capacity for forests to consume and store carbon from the atmosphere.

The results were not comforting.

In fact, they cast doubt over many of the climate models being used to predict carbon levels into the future.

Professor Belinda Medlyn has published a significant study into the capacity of mature trees to capture and sequester carbon.
University of Western Sydney

A forest of cranes

In a unique experiment, Professor Belinda Medlyn and her team from Western Sydney University pumped carbon from a commercial supplier into a forest of 90-year-old trees.

They laid pipelines and built tubular structures in the forest to deliver the carbon into the air above the canopy.

For four years they kept the carbon levels 38 per cent higher than normal while they tracked the movement of carbon through the forest ecosystem and they built cranes to take them high enough to measure the results.

They looked at how the trees and the plants in the understory take up the CO2 and found that it passes through the ecosystem in a number of different ways, according to Professor Medlyn.

"Some of the carbon stays in the plants, some of it is eaten by insects, some of it is passed onto symbiotic fungi, some of it goes into the soil where it becomes food for soil micro-organisms."

The results

Their research showed that mature trees could consume an additional 12 per cent of carbon at elevated levels, but that it wasn't sequestered.

"Instead, the majority of the extra carbon was emitted back into the atmosphere via several respiratory fluxes, with increased soil respiration alone accounting for half of the total uptake surplus," Professor Medlyn said.

The explanation, according to Professor Medlyn, was in the soil.

"The soil that they're growing on is fairly poor. It doesn't have a lot of nutrients in it," she said.

"The plants need those nutrients to grow, so it seems what they've done when they've been given extra carbon is just to use that to go looking for extra nutrients."

Implications for global climate models

If mature trees can't store the rising levels of carbon in the atmosphere, then models based on the idea that plants will respond to increased levels of CO2 with extra growth may be wrong.

"At the moment those global calculations assume that mature forests will store will store extra CO2 as concentrations go up, but our results are implying that mature forests can't keep doing that into the future," Professor Medlyn said.

Mature trees also store a lot of carbon, so old forest still need to be protected, said Professor Medlyn.

"They do have a lot of carbon stored in them, it's just they won't keep on taking up more carbon into the future," she said.

CSIRO cautious

Carbon was piped in from a commercial source and then tubes elevated it above the canopy, raising carbon levels by 38 per cent for the study.
University of Western Sydney

Pep Canadell is the executive director of the global carbon project at the CSIRO's climate research centre.

He agreed the findings of the study, published in Nature magazine, had the potential to change the global models used to predict CO2 levels into the future.

However, he said, more work needed to be done to see if other mature forests responded in the same way, and that two other studies were underway in England and Scotland.

"The big challenge is to begin research across the world to understand if it's common or not common at all," he said.

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