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Study reveals unexpected rise in potent greenhouse gas

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Jan. 21 (UPI) — Scientists had expected the levels of HFC-23, a type of hydrofluorocarbon and a potent greenhouse gas, to drop in the latest global survey of greenhouse gas emissions. Instead, atmospheric concentrations of HFC-23 are rising.

HFC-23 is the byproduct of the production of HCFC-22, another hydrofluorocarbon that is commonly used in cooling systems in developing economies. India and China are two of the largest emitters of HFC-23, but in 2015, the two nations promised to rapidly reduce their HFC-23 emissions.

After making the pledge, officials in China and India reported tremendous progress with their HFC-23 abatement program, with the expectation that HFC-23 emissions would drop to nearly zero by 2017.

A new study, published Tuesday in the journal Nature Communications, suggests the opposite has happened.

Authors of the new study assumed China and India’s reported progress was real, and would lead to reduced concentration of HFC-23 in the atmosphere.

“We had no particular reason to distrust the reports. We were motivated to write the paper because the reported reductions were so dramatic,” study co-author Matthew Rigby, an atmospheric chemist at the University of Bristol in Britain, told UPI in an email. “Based on the reported values, we were expecting to see global atmospheric concentrations stabilize, following decades of growth. So it was a surprise to see them continue to grow, and in fact, grow at a faster rate than ever before.”

Rigby is a member of the Advanced Global Atmospheric Gases Experiment, UGAGE, which measure greenhouse gas concentrations in the atmosphere at test sites around the globe.

The latest findings revealed a significant global rise in HFC-23 in 2017, but the data doesn’t pinpoint the exact source of the increase. Rigby and his colleagues acknowledged that their study doesn’t prove China and India failed to execute their HFC-23 abatement programs.

“From our analysis, we cannot definitively say that China and India have not achieved their reported emission reductions,” lead study author Kieran Stanley, a post-doctoral researcher at the Goethe University Frankfurt in Germany, told UPI. “However, seeing as China and India account for 75 percent of the total global HCFC-22 production in 2017, it is highly likely that China’s reported emissions reductions haven’t taken place.”

Because India’s HCFC-22 production accounts for just 7 percent of global production, it’s harder to guess how much progress the country has made in its efforts to reduce HFC-23 emissions.

According to Stanley, had China and India truly made the emissions reduction progress they reported, that would mean large amounts of illegal, unreported HCFC-22 were manufactured in 2017. If that had happened, Stanley said the hydrocarbon’s price should have dropped. It didn’t.

After the ozone-eating gases, chlorofluorocarbons, or CFCs, were banned by the Montreal Protocol, most industries adopted a variety of alternative gases — hydrofluorocarbons. While most of theses gases are less harmful to the ozone layer, some feature a greenhouse gas effect.

In 2016, parties to the Montreal Protocol signed the Kigali Amendment, aiming to reduce the warming impact of HFCs.

HFC-23’s greenhouse gas effect is particularly potent. Just 1 metric ton of HFC-23 is equivalent to the greenhouse gas effect of 12,000 metric tons of carbon dioxide.

This isn’t the first time scientists have found concentrations of a gas regulated by the Montreal Protocol and its amendments. In 2018, scientists found evidence of a dramatic rise in the ozone-eating gas CFC-11. Investigations revealed China’s foam industry as the primary driver of the emissions increase.

“These two findings do suggest that monitoring of the chemical industry may need to be improved in China,” Rigby said. “In light of the finding of new emissions of CFC-11 from China, the government has announced additional monitoring initiatives focused on ozone depleting substances. Hopefully, they will also be able to look into these continuing emissions of the greenhouse gas, HFC-23.”



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Clouds make newer climate models more realistic, but also less certain

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June 24 (UPI) — Efforts to improve the precision with which climate models simulate cloud processes have yielded more realistic models. New research suggests these efforts have also introduced greater uncertainty, according to a study published Wednesday in the journal Science Advances.

When the latest generation of climate models started producing results last year, researchers noticed that several models were predicting higher amounts of warming than previous models. The results of the new models inspired news headlines that suggested global warming might be worse than previously thought.

As researchers with the Coupled Model Intercomparison Project, CMIP6, soon found out, a few of the latest generation of models predicted smaller levels of warming than previous models. To identify the cause of this uncertainty, CMIP6 researchers decided some historical context was needed.

One way to measure and compare the predictions of different climate models is by calculating the equilibrium climate sensitivity, or ECS.

“It’s kind of an abstract measure, but it’s one these metrics that has been around for a long time,” Gerald Meehl, a senior scientist at the National Center for Atmospheric Research, told UPI.

Essentially, scientists double the CO2 in a model and let the simulation run its course until the climate stabilizes. Each model — and each new generation of models — produces a narrow range of warming, between 1.5 to 4.5 degrees Celsius, or 2.7 to 8.1 degrees Fahrenheit.

“This kind of range has been out there for some time, and with each successive generation of models has produced about the same range in terms of degrees,” Meehl said. “With the latest generation of models, the average warming has stayed roughly the same, but the range has gotten bigger than ever — at both the low and the high end.”

When Meehl and his colleagues asked members of the groups responsible for the 39 new CMIP6 models why they thought the ECS value got bigger, most of them pointed to clouds.

To improve the accuracy of the latest generation of climate models, scientists have worked hard to simulate small-scale cloud processes. But these efforts have introduced a variety of new interactions between clouds and tiny particles called aerosols — interactions that can produce contradictory results.

“For example, if you have polluted air, particularly sulfur dioxide, that can influence clouds. Sulfur dioxide is emitted from cars and factories, and it goes into the air and forms sulfate aerosols,” Meehl said. “When you see the sky and it looks orange and hazy, chances are that a lot of that is caused by an abundance of sulfate aerosols.”

According to Meehl, these aerosols operate as cloud condensation nuclei. When these aerosols seed clouds, they seed clouds with a lot more tiny droplets.

“That increased number of small droplets makes the cloud brighter, and it’s going to reflect more sunlight and have a cooling effect,” Meehl said.

But this phenomena, now rendered more precisely in climate models, can also yield the opposite effect.

“On the other hand, you’ve formed all these droplets in the sky, but the aerosols absorb some sunlight, warm the air, and evaporate some of the droplets and that reduces the amount of clouds,” Meehl said. “That allows a little more sun into the system, and now you have a warming effect.”

Cloud-aerosol interactions are just one example of new simulated intricacies that offer both greater realism and greater uncertainty. According to Meehl, there are a variety of interacting processes involving a variety of different cloud types at different altitudes.

“With more interacting processes, your level of uncertainty can go up,” he said.

But ECS isn’t the only way to test and compare climate models. Most climate modelers prefer to use transient climate response, or TCR.

“You increase CO2 at 1 percent per year, compounded, until the time you double the amount of carbon dioxide, which is usually about 70 years,” Meehl said.

TCR works on a smaller timescale and works more like actual climate change. When scientists calculated the TCR range for the newest generation of climate models, they got the same average warming value but a smaller range.

Meehl and his colleagues shared the ECS and TCR values produced by the latest CMIP6 models in the new paper.

In addition to putting the latest generation of climate models into historical context, Meehl hopes the new study will inspire cloud modeling improvements.

“We’re doing a better job of simulating the clouds themselves, but now we have these different feedbacks that give you more uncertainty,” he said.

Now that researchers have highlighted this uncertainty, Meehl hopes climate research institutions and the climate modeling community will work to address the issue by directing more funds to relevant observational and analysis programs.

“You can’t simulate what you don’t understand,” Meehl said.

And to understand how exactly clouds will effect climate and vice versa, in the future, scientists need more robust observational programs and better satellite measurements.



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SpaceX launch Friday would boost Starlink network to nearly 600

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Astronauts return to space from U.S. soil

NASA astronauts Doug Hurley (L) and Bob Behnken, who flew the Crew Dragon spacecraft to the International Space Station, brief mission controllers about their experience in the new vehicle on June 1. Photo courtesy of NASA



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Antarctic sea ice loss is good news for the continent’s penguins

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June 25 (UPI) — While climate scientists worry about the loss of sea ice in Antarctica, penguins are flapping their flippers in applause. According to a new study, published this week in the journal Science Advances, many penguins prefer the Southern Ocean unfrozen — the less sea ice, the better.

Researchers had previously illuminated a link between sea ice extent in Antarctica and breeding success among Adelie penguin colonies, but a correlation doesn’t prove causation, and so scientists decided to investigate further.

To find out what might explain the positive impact of reduced sea ice coverage on breeding success, scientists strapped a trio of instruments to several dozen penguins. The combination of GPS trackers, accelerometers and video cameras helped scientists track how the movements and behaviors changed over the course of several years, as sea ice extents waxed and waned.

“What is new in this study is that we used a variety of electronic tags to record penguin foraging behavior in the greatest detail yet, and found mechanistic link among sea ice, foraging behavior, and breeding success,” lead researcher Yuuki Watanabe, scientist at the National Institute of Polar Research, told UPI in an email.

The novel data revealed the ways in which ice coverage in Antarctica affects the way penguins move across their environs and access food resources.

“In the ice-covered seasons, penguins traveled slowly by walking and needed to find cracks in the ice, where they dived repeatedly,” Watanabe said. “They were able to dive only through cracks, which also means that the competition among penguins was severe.”

The data also showed that, not surprisingly, penguins move much more efficiently in the water than on ice. Adelie penguins travel four times faster by swimming than by walking.

When sea extent was minimal, data showed the penguins were able to travel more easily, swimming and diving wherever they pleased.

“They came back to the nest quickly, which means that chicks waiting at the nest had food more often,” Watanabe said. “Overall, foraging conditions improved by the loss of sea ice, which directly linked to improved breeding success. Put very simply, penguins are happier with less sea ice because they swim.”

Less sea ice also allows more sunlight to enter the ocean, fueling larger krill blooms. Krill serve as the main source of food for Adelie penguins.

The latest findings don’t hold for all of Antarctica, and in future studies, researchers hope to explore the effects of sea ice extent on different penguin species living in different parts of the continent.

“The relationship between sea ice and penguin reproductive success is apparently different in maritime Antarctica (e.g. Antarctic Peninsula) where sea ice is normally sparse,” Watanabe said. “There, penguins look happier with more sea ice, but mechanics are unclear. I would like to conduct research in that region to understand the general patterns over the whole Antarctica.”



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