Climate Change ☀️
China’s Emissions of Ozone-Harming Gas Are Declining, Studies Find
Emissions from China of a banned gas that harms Earth’s ozone layer have sharply declined after increasing for several years, two teams of scientists said Wednesday, a sign that the Beijing government had made good on vows to crack down on illegal production of the industrial chemical.

The findings ease concerns that increased emissions of the gas, CFC-11, would slow progress in the decades-long environmental struggle to repair the ozone layer, which filters ultraviolet radiation from the sun that can cause skin cancer and damage crops.

“We see a huge decline both in global emission rates and what’s coming from Eastern China,” said Stephen A. Montzka, a research chemist with the National Oceanic and Atmospheric Administration and the lead author of one of the studies. Work by Dr. Montzka and others three years ago first revealed the illegal emissions.

“It looks like there’s been a substantial response, potentially as a result of us raising a flag and saying, ‘Hey, something’s not happening as it should,’” Dr. Montzka said.

Matthew Rigby, an atmospheric chemist at the University of Bristol in England and an author of the second study, said that if emissions had not declined, “we could be seeing a delay in ozone recovery of years.” As of now, full recovery is still expected by the middle of the century.

... Chemical traders in Shandong, a heavily industrialized province in Eastern China where CFC-11 was widely used for making insulating foams, said trade in the banned gas had largely dried up. “It hasn’t disappeared entirely, but it’s much scarcer than before,” Gao Shang, a chemical merchant in Shandong, said in a telephone interview.

CFC-11 was outlawed a decade ago under the Montreal Protocol, the treaty established in the 1980s, when research revealed its effects on atmospheric ozone, along with the effects of similar widely used chemicals.

... CFC-11 has also been used in refrigeration equipment. As the gear ages, and as foams containing CFC-11 degrade over time, the gas will slowly be released. Although the size of this “bank” of CFC-11 is not precisely known, it is accounted for by the protocol, and is one reason full ozone recovery will take decades.

... Susan Solomon, an atmospheric chemist at the Massachusetts Institute of Technology who was not involved in the research, said the work was “a real triumph for science.”

But the problem is not over, Dr. Solomon said, because in addition to CFC-11, there are other, similar chemicals being emitted. “There’s a whole zoo of molecules,” she said, and although the amounts are smaller, they add up.

They also are potent greenhouse gases, she said, although their contribution to warming is much less than the far more prevalent heat-trapping gases like carbon dioxide and methane. “The chemical industry worldwide is still not monitored closely enough for us to actually be confident in how much greenhouse gases they’re making and how much ozone-depleting gases they are making,” she said.
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True Crime With a Climate Connection
Automakers are starting to get more serious about the transition to electric vehicles, and that means they’re going to need rechargeable batteries. Lots of them.

To make those batteries, you need specific precious metals. And they’re getting more expensive. The price of one, rhodium, has gone from about $640 an ounce five years ago to a record $21,900 an ounce this year.

That steep increase isn’t only because of demand from battery producers. The rare metals are also used in the catalytic converters that help to scrub emissions from traditional gas-powered car and truck tailpipes. That means increasingly strict emissions rules are also increasing demand.

It also means that theft is rising sharply across the country.

In order to steal the rhodium and other metals, thieves are slithering under those vehicles in parking lots and driveways around the country and hacking off the catalytic converters.
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Rapid ice retreat during last deglaciation parallels current melt rates
Imagine an ice chunk the size of Hawaii disappearing, almost instantaneously, from an ice sheet. That is what happened in the Storfjorden Trough in the Arctic Ocean some 11,000 years ago.

Ten thousand square kilometres of ice disappeared in a blink of an eye from an ice sheet in the Storfjorden Trough offshore Svalbard, a new study shows. This dramatic break off was preceded by quite a rapid melt of 2.5 kilometres of ice a year. This parallels the current melt rates in Antarctica and Greenland and worries the scientists behind the study.

"Our measurements of the ice retreat in Storfjorden Trough show that the prevailing conditions to the great break off, match what we see in Antarctica and Greenland today. It is uncanny.
There are new studies published almost weekly, that show that the retreat of current ice sheets is two to four km a year and that it's speeding up." Says CAGE-professor and first author Tine Lander Rasmussen.

The last deglaciation, 20,000 to 10,000 years ago, was a period of coexisting global warming and rapidly shrinking ice sheets. But stating the actual correlation between the two is not as simple as it sounds. The period in question was climatically unstable, and big melts were interrupted by re-freezing and formation of new ice. The speed of the ice retreat, relative to climatic changes, has therefore been difficult to establish.

... The periods of extremely rapid ice sheet retreats are consistently correlating with periods of global warming of oceans and temperature. This is mirrored in ice sheet retreat from other eight Northern Norwegian fjord systems.

"This is strengthening our hypothesis that an increase in ocean temperature and global warming is the direct cause of the chain of the events leading up to the dramatically rapid ice sheet disintegration." Says Rasmussen.

This gives some alarming perspectives on present-day outlook. The great melt of the glacial maximum to the Holocene was 10,000 years in the making. The present climate change is much more rapid.
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Can These Hedge Trimmers With Fins Avoid a Brush With Extinction?
Sawfish look something like hedge trimmers with fins and can reach lengths of 17 feet. To Jasmin Graham, president and chief executive of Minorities in Shark Sciences, it’s sometimes hard to believe such weird fish exist.

“They look so intimidating if you look at them from the top down,” she said. But from the bottom, “they have these cute, adorable little gray mouths that kind of look like they’re smiling.”

At least some sawfish truly have something to smile about. The animals, which are a kind of ray, face a variety of threats around the world, including habitat loss and entanglement in fishing nets. But a pair of recent studies, one led by Ms. Graham and colleagues in Florida, reveals glimmers of hope for the species in some parts of the world. But the research also highlights regions where the fish are vanishing, and points to work that is needed to prevent them from disappearing from more places.

With the model, they tested how habitat, fishing pressure and socioeconomics affect populations, ranking countries by sawfish extinction risk. What emerged as key for healthy populations of all sawfish species, the study found, is availability of mangrove habitat combined with facing less pressure from fishing.

Colin Simpfendorfer, a sawfish expert at James Cook University in Australia, commended the study, saying that “it’s not just an analysis of where, but also what needs to be done.”

Ms. Yan’s international research was complemented by the American team Ms. Graham led. That study, published in January in Endangered Species Research, showed that the smalltooth sawfish’s stronghold within the United States is still mainly restricted to Florida but it may be starting to expand. By tracking the fish with passive acoustic tags and an array of receivers, her team recently detected them as far north as Brunswick, Ga.

Though international trade in sawfish and their parts is banned under the Convention on International Trade in Endangered Species of Flora and Fauna, intentional killing and by-catch still occurs. And countries have an imperfect record at enforcing prohibitions on trade in the fish’s fins and teeth, which are still prized as trophies and used in some cultural settings.

When unintentionally captured — shrimp trawls are emerging as a key threat, with mitigation efforts being studied — sawfish often die needlessly because they are so tricky to untangle or release, says John Carlson, a sawfish researcher at the National Oceanic and Atmospheric Administration Fisheries. Their toothy rostrum “gets caught in everything. It’s their Achilles’ heel,” he says.

And with mangroves the key sites for aiding conservation, Dr. Carlson’s sawfish research is trying to understand why some mangrove patches, though superficially identical, are favored over others.

After two decades of increasing attention and targeted work by scientists and conservationists, “people’s appreciation of sawfish is really way up,” said Sonja Fordham, a co-author of Ms. Yan’s research and president of Shark Advocates International. But she cautions that “we still have a long way to go and it’s really a race against time.”
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Climate change, periodic modification of Earth’s climate brought about as a result of changes in the atmosphere as well as interactions between the atmosphere and various other geologic, chemical, biological, and geographic factors within the Earth system.

Source: Climate change - Evidence for climate change | Britannica
Climate Change is the defining issue of our time and we are at a defining moment. From shifting weather patterns that threaten food production, to rising sea levels that increase the risk of catastrophic flooding, the impacts of climate change are global in scope and unprecedented in scale. Without drastic action today, adapting to these impacts in the future will be more difficult and costly.

Source: Climate Change | United Nations