Posts Tagged ‘climate change’

Researchers have engineered Escherichia coli bacteria to make energy exclusively from carbon dioxide, according to a paper published November 27 in Cell.

E. coli are normally heterotrophs—organisms that get their energy sources from ingesting organic compounds, such as glucose—but the new study shows that they can be turned into autotrophs, making their own energy by turning carbon dioxide from the atmosphere into biomass.

“I find it fundamentally amazing that an organism which evolved over billions of years to live a heterotrophic lifestyle can so quickly and completely change into an autotroph,” Dave Savage, a biochemist at University of California, Berkeley, who was not involved with the study, tells The Scientist in an email. “It suggests that metabolism is extremely malleable.”

This process of using inorganic carbon to make biomass, called carbon fixation, could be used to solve “some of the biggest challenges of humanity today,” Ron Milo, a systems biologist at the Weizmann Institute of Science in Israel and the lead author of the paper, tells The Scientist. For example, increasing carbon fixation in plants generates more biomass, which could increase the world’s food supply.

The team set out to make E. coli—a “very genetically malleable model organism,” says Milo—fix carbon as a step toward sustainable industrial processes such as creating biofuel.

E. coli doesn’t normally have molecular mechanisms in place to use CO2, so the researchers gave it genes for the ability to fix carbon that were based on the gene sequence of carbon-fixing Pseudomonas bacteria. These changes weren’t enough to force the bacteria to switch to being autotrophic, so the team also disabled three genes involved in heterotrophic metabolism and put the bacteria into growth chambers with limited amounts of sugar, which starved them. In this environment, there was an advantage for bacteria that used CO2 instead of the finite sugar supply, and the researchers wanted to see if the bacteria could evolve to only use CO2.

The E. coli were grown on sodium formate, a carbon molecule that donates the necessary electrons during the process of making energy, but doesn’t contribute to biomass. The air in the growth chambers was also enriched with carbon dioxide.

After approximately 200 days, the bacteria relied completely on carbon dioxide from the air to generate biomass while taking in formate as a necessary ingredient for the chemical reactions. When the scientists analyzed the bacterial genome, they found that the bacteria evolved to use carbon dioxide as their energy source after as few as 11 mutations. Some of the changes occurred in genes related to carbon fixation, while others were in genes that are known to mutate in other lab evolution experiments or have no known role in energy production from CO2.


Heterotrophic E. coli (left) produce biomass from sugar, but lab-evolved autotrophic E. coli from the new study (center) use CO2 instead. The authors envision autotrophic E. coli that use renewable energy and have no net carbon emissions in the future (right).

“It’s a proof of concept for the field, that you can really rewire . . . the metabolic features of living organisms from scratch. It’s an exciting step forward,” Tobias Erb, a synthetic biologist at the Max Planck Institute for Terrestrial Microbiology in Germany who wrote a commentary on the study, tells The Scientist. However, “if the strain that they created [is] of biotechnological relevance in the future . . . I think is still up to debate,” he says.

For instance, the autotrophic E. coli currently produce more carbon dioxide as a byproduct than they take in. This could be solved by producing formate from carbon dioxide in the future, so that there are no net carbon dioxide emissions.

In addition, the researchers used high carbon dioxide levels in the bacteria’s growth chambers—around 10 percent of the air—but it’s only 0.04 percent of Earth’s atmosphere. “We’re interested to see if we could move it towards ambient carbon dioxide levels, meaning that one could use the ambient atmosphere that has much less [carbon dioxide], 400 parts per million,” says Milo.

“It’s an interesting concept now. Whether it actually is something that becomes useful in terms of application, that’s another question,” Patrik Jones, who studies microbial metabolic engineering at Imperial College London and was not involved with the study, tells The Scientist. “It’s definitely a step towards that direction . . . But then I think it’s important to realize that there are more steps needed in order to utilize this.”

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Researchers have engineered Escherichia coli bacteria to make energy exclusively from carbon dioxide, according to a paper published today (November 27) in Cell.

E. coli are normally heterotrophs—organisms that get their energy sources from ingesting organic compounds, such as glucose—but the new study shows that they can be turned into autotrophs, making their own energy by turning carbon dioxide from the atmosphere into biomass.

“I find it fundamentally amazing that an organism which evolved over billions of years to live a heterotrophic lifestyle can so quickly and completely change into an autotroph,” Dave Savage, a biochemist at University of California, Berkeley, who was not involved with the study, tells The Scientist in an email. “It suggests that metabolism is extremely malleable.”

This process of using inorganic carbon to make biomass, called carbon fixation, could be used to solve “some of the biggest challenges of humanity today,” Ron Milo, a systems biologist at the Weizmann Institute of Science in Israel and the lead author of the paper, tells The Scientist. For example, increasing carbon fixation in plants generates more biomass, which could increase the world’s food supply.

The team set out to make E. coli—a “very genetically malleable model organism,” says Milo—fix carbon as a step toward sustainable industrial processes such as creating biofuel.

E. coli doesn’t normally have molecular mechanisms in place to use CO2, so the researchers gave it genes for the ability to fix carbon that were based on the gene sequence of carbon-fixing Pseudomonas bacteria. These changes weren’t enough to force the bacteria to switch to being autotrophic, so the team also disabled three genes involved in heterotrophic metabolism and put the bacteria into growth chambers with limited amounts of sugar, which starved them. In this environment, there was an advantage for bacteria that used CO2 instead of the finite sugar supply, and the researchers wanted to see if the bacteria could evolve to only use CO2.

The E. coli were grown on sodium formate, a carbon molecule that donates the necessary electrons during the process of making energy, but doesn’t contribute to biomass. The air in the growth chambers was also enriched with carbon dioxide.

After approximately 200 days, the bacteria relied completely on carbon dioxide from the air to generate biomass while taking in formate as a necessary ingredient for the chemical reactions. When the scientists analyzed the bacterial genome, they found that the bacteria evolved to use carbon dioxide as their energy source after as few as 11 mutations. Some of the changes occurred in genes related to carbon fixation, while others were in genes that are known to mutate in other lab evolution experiments or have no known role in energy production from CO2.

Heterotrophic E. coli (left) produce biomass from sugar, but lab-evolved autotrophic E. coli from the new study (center) use CO2 instead. The authors envision autotrophic E. coli that use renewable energy and have no net carbon emissions in the future (right).
GLEIZER ET AL.
“It’s a proof of concept for the field, that you can really rewire . . . the metabolic features of living organisms from scratch. It’s an exciting step forward,” Tobias Erb, a synthetic biologist at the Max Planck Institute for Terrestrial Microbiology in Germany who wrote a commentary on the study, tells The Scientist. However, “if the strain that they created [is] of biotechnological relevance in the future . . . I think is still up to debate,” he says.

For instance, the autotrophic E. coli currently produce more carbon dioxide as a byproduct than they take in. This could be solved by producing formate from carbon dioxide in the future, so that there are no net carbon dioxide emissions.

In addition, the researchers used high carbon dioxide levels in the bacteria’s growth chambers—around 10 percent of the air—but it’s only 0.04 percent of Earth’s atmosphere. “We’re interested to see if we could move it towards ambient carbon dioxide levels, meaning that one could use the ambient atmosphere that has much less [carbon dioxide], 400 parts per million,” says Milo.

“It’s an interesting concept now. Whether it actually is something that becomes useful in terms of application, that’s another question,” Patrik Jones, who studies microbial metabolic engineering at Imperial College London and was not involved with the study, tells The Scientist. “It’s definitely a step towards that direction . . . But then I think it’s important to realize that there are more steps needed in order to utilize this.”

Emily Makowski is an intern at The Scientist. Email her at emakowski@the-scientist.com.

https://www.the-scientist.com/news-opinion/lab-evolved-e–coli-makes-energy-solely-from-carbon-dioxide-66788?utm_campaign=TS_DAILY%20NEWSLETTER_2019&utm_source=hs_email&utm_medium=email&utm_content=80070748&_hsenc=p2ANqtz-_mk5jB1Vyqx3xPsKPzk1WcGdxEqSmuirpfpluu4Opm4tMO6n7rXROJrCvQp0yKBw2eCo4R4TZ422Hk6FcfJ7tDWkMpyg&_hsmi=80070748

By SUSANNE RUST

Five thousand miles west of Los Angeles and 500 miles north of the equator, on a far-flung spit of white coral sand in the central Pacific, a massive, aging and weathered concrete dome bobs up and down with the tide.

Here in the Marshall Islands, Runit Dome holds more than 3.1 million cubic feet — or 35 Olympic-sized swimming pools — of U.S.-produced radioactive soil and debris, including lethal amounts of plutonium. Nowhere else has the United States saddled another country with so much of its nuclear waste, a product of its Cold War atomic testing program.

Between 1946 and 1958, the United States detonated 67 nuclear bombs on, in and above the Marshall Islands — vaporizing whole islands, carving craters into its shallow lagoons and exiling hundreds of people from their homes.

U.S. authorities later cleaned up contaminated soil on Enewetak Atoll, where the United States not only detonated the bulk of its weapons tests but, as The Times has learned, also conducted a dozen biological weapons tests and dumped 130 tons of soil from an irradiated Nevada testing site. It then deposited the atoll’s most lethal debris and soil into the dome.

Now the concrete coffin, which locals call “the Tomb,” is at risk of collapsing from rising seas and other effects of climate change. Tides are creeping up its sides, advancing higher every year as distant glaciers melt and ocean waters rise.

Officials in the Marshall Islands have lobbied the U.S. government for help, but American officials have declined, saying the dome is on Marshallese land and therefore the responsibility of the Marshallese government.

“I’m like, how can it [the dome] be ours?” Hilda Heine, the president of the Republic of the Marshall Islands, said in an interview in her presidential office in September. “We don’t want it. We didn’t build it. The garbage inside is not ours. It’s theirs.”

To many in the Republic of the Marshall Islands, Runit Dome is the most visible manifestation of the United States’ nuclear legacy, a symbol of the sacrifices the Marshallese made for U.S. security, and the broken promises they received in return.

They blame the United States and other industrialized countries for global climate change and sea level rise, which threaten to submerge vast swaths of this island nation’s 29 low-lying atolls.

Over the last 15 months, a reporting team from the Los Angeles Times and Columbia University’s Graduate School of Journalism made five trips to the Marshall Islands, where they documented extensive coral bleaching, fish kills and algae blooms — as well as major disease outbreaks, including the nation’s largest recorded epidemic of dengue fever. They interviewed folk singers who lost their voices to thyroid cancers and spent time in Arkansas, Washington and Oregon, where tens of thousands of Marshallese have migrated to escape poverty and an uncertain future.

Marshallese leaders acknowledge that America doesn’t bear full responsibility for their nation’s distress. But they say the United States has failed to take ownership of the environmental catastrophe it left behind, and they claim U.S. authorities have repeatedly deceived them about the magnitude and extent of that devastation.

A Times review of thousands of documents, and interviews with U.S. and Marshallese officials, found that the American government withheld key pieces of information about the dome’s contents and its weapons testing program before the two countries signed a compact in 1986 releasing the U.S. government from further liability. One example: The United States did not tell the Marshallese that in 1958, it shipped 130 tons of soil from its atomic testing grounds in Nevada to the Marshall Islands.

U.S. authorities also didn’t inform people in Enewetak, where the waste site is located, that they’d conducted a dozen biological weapons tests in the atoll, including experiments with an aerosolized bacteria designed to kill enemy troops.

U.S. Department of Energy experts are encouraging the Marshallese to move back to other parts of Enewetak, where 650 now live, after being relocated during the U.S. nuclear tests during the Cold War. But many Marshallese leaders no longer trust U.S. assurances of safety.

“We didn’t know the Runit Dome waste dump would crack and leak…. We didn’t know about climate change,” said Jack Ading, a Marshallese senator from Enewetak Atoll. “We weren’t nuclear scientists who could independently verify what the U.S. was telling us. We were just island people who desperately wanted to return home.”

Adding to the alarm is a study published this year by a team of Columbia University scientists showing levels of radiation in some spots in Enewetak and other parts of the Marshall Islands that rival those found near Chernobyl and Fukushima.

Such discoveries could give Marshallese leaders fresh ammunition to challenge the 1986 compact, which is up for renegotiation in 2023, and also to press the United States to honor property and health claims ordered by an international tribunal.

The tribunal, established by the two countries in 1988, concluded the United States should pay $2.3 billion in claims, but Congress and U.S courts have refused. Documents show the U.S. paid just $4 million.

The U.S. position is that it has already paid more than $600 million for the resettlement, rehabilitation and radiation-related healthcare costs of communities affected by the nuclear testing, said Karen Stewart, the U.S. ambassador to the Republic of the Marshall Islands. She said inflation brings the number closer to $1 billion.

“The United States recognizes the effects of its testing and has accepted and acted on its responsibility to the people of the Republic of the Marshall Islands,” Stewart said in a statement.

In September, the Marshallese parliament, the Nitijela, approved a national nuclear strategy, which calls for a risk analysis and environmental survey of Runit Dome, an assessment of legal options for its cleanup and a new attempt to secure the $2.3 billion ordered by the tribunal.

Last month, Marshall Islands lawmakers called on the international community to reduce greenhouse gases causing what they declared to be a “national climate crisis.”

China is taking an increasing interest in the Marshall Islands and other Pacific island nations, in part because of their strategic location and Beijing’s interest in reducing U.S. influence in the region. Those inroads by China have alarmed U.S. leaders, forcing them to pay more attention to the grievances of Marshallese leaders such as Heine.

“This heightened interest,” Heine said, “should bode well for us.”

From the U.S. mainland, it takes more than a day to fly to the Marshall Islands, and only one commercial airline makes the trip.

The “Island Hopper,” United Airlines Flight 154, starts at Honolulu, making stops in the Marshall Islands at Majuro and Kwajalein before heading west toward the Micronesian islands of Kosrae, Pohnpei and Chuuk, and finally terminating in Guam.

The next day, it doubles back.

As it approaches Majuro, the blue-scape of the ocean is broken by an oblong necklace of white-coral-beached islands, dotted with coconut, pandanus and breadfruit trees.

The Marshall Islands’ atolls are the remnants of ancient volcanoes that once protruded from these cerulean seas. They were settled 3,000 years ago by the ancestors of present-day Marshallese who crossed the ocean on boats from Asia and Polynesia. For American officials in the mid-1940s, this 750,000-square-mile expanse of ocean, nearly five times larger than the state of California, must have seemed like a near-perfect spot to test their growing atomic arsenal.

“The Marshall Islands were selected as ground zero for nuclear testing precisely because colonial narratives portrayed the islands as small, remote and unimportant,” said Autumn Bordner, a former researcher at Columbia University’s K=1 Project, which has focused on the legacy of nuclear testing in the Marshall Islands, and now a research fellow in ocean law and policy at UC Berkeley’s Center for Law, Energy & the Environment.

Nerje Joseph, 72, was a witness to the largest thermonuclear bomb tested by the United States: the Castle Bravo detonation. She was 7 years old at the time, living with her family in Rongelap Atoll, 100 miles east of Bikini Atoll — a tropical lagoon commandeered for nuclear testing.

On March 1, 1954, Joseph recalls waking up and seeing two suns rising over Rongelap. First there was the usual sun, topping the horizon in the east and bringing light and warmth to the tropical lagoon near her home. Then there was another sun, rising from the western sky. It lighted up the horizon, shining orange at first, then turning pink, then disappearing as if it had never been there at all.

Joseph and the 63 others on Rongelap had no idea what they had just witnessed. Hours later, the fallout from Castle Bravo rained down like snow on their homes, contaminating their skin, water and food.

According to Joseph and government documents, U.S. authorities came to evacuate the Rongelapese two days later. By that time, some islanders were beginning to suffer from acute radiation poisoning — their hair fell out in clumps, their skin was burned, and they were vomiting.


Nerje Joseph, 72, was 7 years old when the United States detonated its largest nuclear bomb. The Castle Bravo test sent a mushroom cloud into the sky and unexpectedly irradiated parts of the northern Marshall Islands that she and her family called home.

“More than any other place, the Marshall Islands is a victim of the two greatest threats facing humanity — nuclear weapons and climate change,” said Michael Gerrard, a legal scholar at Columbia University’s law school. “The United States is entirely responsible for the nuclear testing there, and its emissions have contributed more to climate change than those from any other country.”

The Castle Bravo test and others in the Marshall Islands helped the U.S. establish the credibility of its nuclear arsenal as it raced against its Cold War adversary, the Soviet Union, to develop new atomic weapons. But the testing came at a horrible price; Joseph and other Marshallese ended up becoming human guinea pigs for U.S. radiation research.

Three years after Castle Bravo, U.S. authorities encouraged Joseph, her family and her neighbors to return to Rongelap.

U.S. government documents from the time show that officials weighed the potential hazards of radiation exposure against “the current low morale of the natives” and a “risk of an onset of indolence.” Ultimately they decided to go forward with the resettlement so researchers could study the effects of lingering radiation on human beings.

“Data of this type has never been available,” Merrill Eisenbud, a U.S official with the Atomic Energy Commission, said at a January 1956 meeting of the agency’s Biology and Medicine Committee. “While it is true that these people do not live the way that Westerners do, civilized people, it is nonetheless also true that they are more like us than the mice.”

The resettlement proved catastrophic for the people of Rongelap. Cancer cases, miscarriages and deformities multiplied. Ten years later, in 1967, 17 of the 19 children who were younger than 10 and on the island the day Bravo exploded had developed thyroid disorders and growths. One child died of leukemia.

In 1985, the people of Rongelap asked Greenpeace to evacuate them again after the United States refused to relocate them or to acknowledge their exposure, according to government documents and news reports from the time.

Joseph, who had her thyroid removed because of her radiation exposure, has spent nearly seven decades taking daily thyroid medication, enabling her body to produce hormones it otherwise would not generate.

A quiet, dignified woman with thick, wavy gray hair, Joseph lives in a cinder-block home in Majuro, the capital, a setting far different from the pristine atoll where she grew up.

Composed of three low-lying islands connected by one flood-prone road, Majuro is long and narrow and home to roughly half the population of the Marshall Islands, about 28,000 people. Taxis crawl the length of this lone road, fitting as many riders into their vehicles as they can accommodate. Visitors opting to walk are encouraged to carry long sticks to beat away packs of feral dogs that roam the streets.

Joseph says she misses her home, but she knows she may never go back.

“We had a oneness when we lived on Rongelap,” she said of her childhood. “We worked together, we ate together, we played together. That has been lost.”

The legacy of the testing program is most evident at Enewetak, an atoll that took the brunt of the United States’ late-stage nuclear detonations before an international ban on atmospheric testing in 1963.

A string of 40 islands to the west of Bikini, Enewetak was once a postcard-perfect ring of coral reefs, white-sand beaches and coconut trees, where roughly 450 dri-Enewetak and dri-Enjebi — the two clans that lived in the atoll — gathered breadfruit and pandanus, and harvested fish and clams from the lagoon.

Between 1948 and 1958, the U.S. military detonated 43 atomic bombs here. After agreeing to a 1958 temporary moratorium on nuclear testing with the United Kingdom and the Soviet Union, the U.S. began using the atoll as a conventional and bioweapons testing ground. For the next 18 years, the U.S. shot ballistic missiles at it from California, tested virulent forms of bacteria on its islands and detonated a series of other large, conventional bombs in the lagoon.

In 1972, after the U.S had nearly exhausted its military interest in the region, it invited the leaders of Enewetak back to see the atoll for the first time since 1946.

According to a Department of Energy report of the event, the Enewetak leaders “were deeply gratified to be able to visit their ancestral homeland, but they were mortified by what they saw.”

The islands were completely denuded. Photos show an apocalyptic scene of windswept, deforested islands, with only the occasional coconut tree jutting up from the ground. Elsewhere, crumbling concrete structures, warped tarmac roads and abandoned construction and military equipment dotted the barren landscape.

The damage they saw on that visit was the result of nearly three decades of U.S. military testing.

The United States had detonated 35 bombs in the Marshall Islands in 112 days in 1958. Nine of these were on Enewetak’s Runit Island. With names such as Butternut, Holly and Magnolia, the bombs were detonated in the sky, underwater and on top of islands.

One test shot, Quince, misfired Aug. 6, 1958, and sprayed plutonium fuel across Runit Island. The Department of Defense and the Lawrence Livermore National Laboratory, which was sponsoring the test, ordered soldiers into the contaminated ground zero to prepare the site for the next bomb, 12 days later.

Soldiers swarmed in with bulldozers and earthmoving equipment, pushing the radioactive soil into big debris piles that they shoved into the lagoon, the ocean or possibly left alone; government reports differ on these details.

What is clear, and which has never been reported before, is that 130 tons of soil transported 5,300 miles from an atomic test site in Nevada was dumped into a 30-foot-wide, 8-foot-deep “conical plug” where the next bomb, Fig, was detonated.

Archived documents suggest the soil was used as part of an experiment, to help scientists understand how soil types contribute to different blast impacts and crater sizes.

Terry Hamilton, a researcher at the Lawrence Livermore National Laboratory and today the Department of Energy’s point person on the Marshall Islands’ nuclear issues, said the soil was clean and taken from Area 10 at the Nevada Test Site. That area of the Nevada site had been the site of two nuclear blasts in 1951 and 1955, according to government records.

“It is appalling that the Marshallese people, and in particular the people of Enewetak, are just learning about this for the first time,” said Sen. Ading, the Marshallese minister of justice, immigration and labor.

A decade later, in 1968, teams from the Department of Defense set up a new experiment. This time, they were testing biological weapons — bombs and missiles filled with bacteria designed to fell enemy troops.

According to a 2002 military fact sheet and Ed Regis, the author of “The Biology of Doom,” U.S. government scientists came to Enewetak with “their boats and monkeys, space suits and jet fighter planes” and then sprayed clouds of biologically enhanced staphylococcal enterotoxin B, an incapacitating biological agent known to cause toxic shock and food poisoning and considered “one of the most potent bacterial superantigens.”

The bacteria were sprayed over much of the atoll — with ground zero at Lojwa Island, where U.S. troops were stationed 10 years later for the cleanup of the atoll.

According to military documents, the weapons testers concluded a single weapon could cover 926.5 square miles — roughly twice the size of modern-day Los Angeles — and produce a 30% casualty rate.

Records of the test, including a two-volume, 244-page account of operation “Speckled Start,” as it was called, are still classified, according to the Defense Technical Information Center, a branch of the Department of Defense.

Today, 40 years after it was constructed, the Tomb resembles an aged, neglected and slightly diminutive cousin of the Houston Astrodome.

Spiderweb cracks whipsaw across its cap and chunks of missing concrete pock its facade. Pools of brown, brackish water surround its base, and vines and foliage snake up its sides.

The Tomb, which was built atop an unlined crater created by a U.S. nuclear bomb, was designed to encapsulate the most radioactive and toxic land-based waste of the U.S. testing programs in Enewetak Atoll. This included irradiated military and construction equipment, contaminated soil and plutonium-laced chunks of metal pulverized by the 43 bombs detonated in this 2.26-square-mile lagoon, according to U.S. government documents.

It took 4,000 U.S. servicemen three years to scoop up 33 Olympic-sized swimming pools’ worth of irradiated soil and two Olympic swimming pools’ worth of contaminated debris from islands across the atoll and dump it into the crater on Runit Island.

Much of it was mixed in a slurry of concrete and poured into the pit, which was eventually capped with a concrete dome. Six men died during the cleanup; hundreds of others developed radiation-induced cancers and maladies that the U.S. government has refused to acknowledge, according to news reports.

Rising seas could unseal a toxic tomb

More than 3.1 million cubic feet of radioactive material lie within a bomb crater that was capped with an 18-inch-thick cover on Runit Island.

What is underneath the dome

Contaminated debris and soil left behind by 43 nuclear bombs detonated in Enewetak Atoll were cemented and enclosed in a crater from one of the nuclear tests. The dome, constructed in the late ’70s, is showing signs of decay. If it crumbles, its radioactive contents will be released into the lagoon and ocean.

“It’s like they say in the Army,” said Bob Retmier, a retired Huntington Beach-based electrician who did two six-month tours of duty at the dome in 1977 and 1978. “They treat us like mushrooms: They feed us crap and keep us in the dark.”

Retmier, who was in Enewetak with Company C, 84th Engineer Battalion out of Schofield Barracks, Hawaii, said he didn’t know he had been working in a radioactive landscape until he read about the dome in The Times this year.

“They had us mixing that soil into cement,” he said. “There were no masks, or respirators, or bug suits, for that matter. My uniform was a pair of combat boots, shorts and a hat. That was it. No shirt. No glasses. It was too hot and humid to wear anything else.”

According to unclassified military documents, the completion of the dome fulfilled “a moral obligation incurred by the United States.”

Marshallese officials say they were never told that U.S. authorities had doubts about the long-term integrity of the dome to safely store waste.

According to a 1981 military document chronicling the construction of the dome, U.S. government officials met Feb. 25, 1975, to discuss various cleanup options — including ocean dumping and transporting the waste back to the U.S. mainland. Many “of those present seemed to realize that radioactive material was leaking out of the crater even then and would continue to do so,” the document reported.

But because the other options were so expensive, they settled on the dome and relied on military personnel to do the cleaning instead of contractors.

At that meeting, a top Pentagon official was asked what would happen if the dome failed and who would be responsible.

“It would be the responsibility of the United States,” said Lt. Gen. Warren D. Johnson of the U.S. Air Force, who was directing the cleanup process through the Defense Nuclear Agency.

Documents show that as construction teams were finishing the dome by capping it with an 18-inch concrete cover, new, highly contaminated debris was discovered.

In the process of adding that material to the waste site, parts of the concrete top were embedded with contaminated metallic debris.

“It was sloppy,” said Paul Griego, who worked as a contract radiochemist for Eberline Instruments in Enewetak while the military built the dome.

The authors of the report noted that because the dome was “designed to contain material and prevent erosion rather than act as a radiation shield,” the radioactive material in the dome cover was no cause for concern.

Today, U.S. officials maintain that the dome has served its “intended purpose” — to hold garbage, not necessarily to be a radiation shield.

That distinction, though, is not well understood in the Marshall Islands, where many assumed the United States built the dome to protect them.

“My understanding from day one is that the dome was to shield the radiation from leaking out,” Ading said.

Soon after the dome was completed, the winter tides washed more than 120 cubic yards of radioactive debris onto Runit’s shores, prompting U.S. authorities to build a small antechamber adjacent to the dome to hold the new “red-level” debris.

When more debris washed up, they built a second, smaller antechamber.

Then they left.

The U.S. scientific expert on Runit Dome is Hamilton, the Energy Department contractor. He began working on radiation issues nearly three decades ago and is widely respected among nuclear scientists and physicists.

In 2012, Hamilton called the waste site a highly radioactive “point source” whose construction was “not consistent” with U.S. Nuclear Regulatory Commission regulations. He also suggested it could possibly release more plutonium into the surrounding environment.

“Any increases in availability of plutonium will have an impact on food security reserves for the local population,” he wrote with two Lawrence Livermore National Laboratory coauthors, noting a “growing commercial export market” for sea cucumbers in the lagoon.

In more recent years, Hamilton’s message has changed: The islands are safe, U.S. researchers are monitoring the situation, and no one should be concerned.

At a May meeting in Majuro, he told an audience of Marshallese dignitaries, politicians and U.S. officials that the Tomb was bobbing with the tides, sucking in and flushing out radioactive water into the lagoon. Moreover, he said, its physical integrity is “vulnerable to leakage and the sustained impacts of storm surge and sea level rise.”

But Hamilton went on to assure them such a scenario was not cause for alarm. Enewetak lagoon is already so contaminated, he said, that any added radiation introduced by a dome failure would be virtually undetectable — in the lagoon, or in the wider ocean waters.

Hamilton has said that his assessment is based on a sampling of U.S. documents from the 1970s and 1980s suggesting that there is far more contamination in Enewetak lagoon than remains inside the dome. He contends the land is safe for habitation and will remain so, even if the dome crumbles and releases its contents into the contaminated lagoon.

Plutonium is a risk to human health only when it is airborne or introduced via a cut in the skin, Hamilton said. The plutonium in the lagoon, he claims, is not a concern.

“Under existing living conditions, there is no radiological basis why I or anyone else should be concerned about living on Enewetak,” Hamilton said in an email, reflecting a position that other experts find perplexing.

“That’s crazy,” said Holly Barker, a University of Washington anthropologist who serves on the Marshall Islands nuclear commission. The whole point of building the Tomb, she said, was to clean up contamination left behind by the U.S. testing programs.

“Does that mean they didn’t clean it up?” she asked.

Asked about his contradictory messages, Hamilton wrote in an email that his earlier assessment was “put forward to help provide a scientific justification” for securing funding and time for a more thorough analysis of the dome.

“People living on Enewetak do not show elevated levels of plutonium in their bodies,” he said, discounting concerns. “This is the ultimate test.”

To many, Hamilton’s most recent position is just another case of the United States moving the goal posts in the Marshall Islands: It promised a thorough cleanup, only to backtrack in the face of new revelations or costs.

Griego, the radiochemist and the New Mexico state commander of the National Assn. of Atomic Veterans, notes that when Hamilton wrote a report for the Department of Energy in 2013 stating that catastrophic failure of the dome would be inconsequential, the report included a mission statement that cast doubt on its scientific integrity.

According to the document, the report’s purpose was to “address the concerns of the Enewetak community” and “help build public confidence in the maintenance of a safe and sustainable resettlement program on Enewetak Atoll.”

Griego worked as a contractor in Enewetak in 1978.

“I saw the water rising and falling as we filled that dome. I know that limestone is porous. And I know how sick people got,” Griego said. “That dome is dangerous. And if it fails, it’s a problem.”

Climate scientists have been nearly unanimous about one thing: The waters around the Marshall Islands are rising — and growing warmer.

On an August day a year ago, tens of thousands of dead fish washed up on the ocean side of Bikini Atoll.

Dick Dieke Jr., one of seven temporary caretakers working for a Department of Energy contractor there, recalls the water being uncomfortable.

“It didn’t feel good to put my feet in it,” he said. “It was too hot.”

Earlier that day, the typically crystalline and azure waters of the Bikini lagoon, near Nam Island, were cloudy and brown. Sea turtles, reef fish and rays swam slowly through the murk, appearing suddenly out of the cloudy bloom only to disappear just as quickly.

Dive computers showed 92-degree temperatures 30 feet below the surface in the lagoon, an area usually no warmer than 86 degrees in August.

It is impossible to say exactly what caused that day’s massive algae bloom and fish kill, but scientists say such marine incidents will occur more frequently as oceans warm from climate change.

“I’ve never seen or heard of a fish kill in Bikini,” Jack Niedenthal, the Marshall Islands’ secretary of health and human services, said in an interview last summer, just a week after the event. “That’s surprising and deeply upsetting.”

Just a few years ago, the northern Marshall Islands were known for their pristine coral reefs, little disturbed by human contact, in part because many of these isles were radiation no-go zones. But during a visit last year, The Times saw vast expanses of bleached and dead coral around Bikini Atoll, a finding that surprised some familiar with the region.

Elora López, a Stanford University doctoral student, accompanied a PBS documentary film team in 2016 to Bikini Atoll to collect coral samples. The reefs — hundreds of miles from the nearest tourist — were healthy.

But when she returned in 2018, using GPS coordinates to find the same location, all of the corals were dead.

Since 1993, sea levels have risen about 0.3 inches a year in the Marshall Islands, far higher than the global average of 0.11 to 0.14 inches. Studies show sea levels are rising twice as fast in the western Pacific than elsewhere.

Based on forecasts by the Intergovernmental Panel on Climate Change, sea levels could rise 4 to 5 feet by the end of the century, submerging most of the Marshall Islands.

Even if seas rose just half that, said Curt Storlazzi, a geoengineer at the United States Geological Survey, the islands would be in trouble — damaging infrastructure and contaminating most groundwater reserves.

“We have a lot of difficult choices to make,” James Matayoshi, the mayor of Rongelap Atoll, said in a September interview. “If the seas don’t stop rising, we’re going to lose some places. Assuming we can save some, we’ll have to decide which islands, which places, for which people. But who gets to do that?”

The thought of abandoning their homeland is unthinkable for many Marshallese, the nation’s president said.

“Many of our people … want to stay here,” Heine said. “For us, for these people, land is a critical part of our existence. Our culture is based on our land. It is part of us. We cannot think about abandoning the land.”

Outbreaks of certain diseases in the Pacific also have been linked to climate change. The Republic of the Marshall Islands is fighting the largest outbreak of dengue fever in its recorded history — more than 1,000 people have been infected, with the outer atolls quarantined to prevent the spread of disease among people with no access to hospital care.

“Most people talk about rising sea levels when it comes to climate change,” said Niedenthal, the health secretary. “Even more immediate and devastating is what has been happening with disease outbreaks. This is the worst outbreak in Pacific history.”

For many Americans, the Marshall Islands are best known for a movie monster and a cartoon icon. Godzilla, the Japanese-inspired monster of the Pacific, was awakened and mutated by the atomic bombs in Bikini Atoll. SpongeBob SquarePants, the Nickelodeon cartoon character, lives with his friends in Bikini Bottom.

A recent review of California-approved high school history textbooks and curricula showed no mention of the Marshall Islands or the U.S. nuclear testing program and human experimentation program there.

Even less widely known are the Marshallese attempts, for the last three decades, to seek compensation from the U.S. for the health and environmental effects of nuclear testing. They’ve been denied standing to sue in U.S. courts, and Congress has declined their requests.

The Nuclear Claims Tribunal — an independent arbiter established by the U.S.-Marshall Islands compact to process and rule on claims — has ruled in their favor, awarding them more than $2 billion in damages. But the U.S. has paid out only $4 million, according to congressional testimony, and no enforcement mechanism exists.

In the last few years, though, the island nation’s claims have begun to get more visibility.

President Heine has achieved near-celebrity status at international events. The Marshall Islands recently secured a seat on the United Nations Human Rights Council, giving the nation another forum in which to raise its concerns.

A geopolitical shift also has given the islands new leverage. China has increased its reach into the central Pacific, providing aid and loans to dozens of nations, surpassing the United States as the region’s largest trade partner.

“China is trying to erode U.S. influence in the region to weaken the U.S. military presence and create an opening for Chinese military access,” according to a 2018 report from the U.S.-China Economic and Security Review Commission, a congressional committee.

In September, two of the United States’ staunchest allies in the Pacific — Kiribati and the Solomon Islands — severed diplomatic ties with Taiwan, embracing China instead.

Washington has greeted those developments with concern.

In August, Secretary of State Michael R. Pompeo flew to Micronesia to meet with the leaders of several Pacific island nations, including the Marshall Islands.

He announced the United States’ intention to extend the compact with the Marshall Islands — providing aid in exchange for a secure military presence, and working rights for Marshallese in the United States.

The announcement came as a surprise to the Marshallese, who were anticipating the expiration in 2023 of their compact, which includes annual grants from the U.S. that total about $30 million a year.

Marshallese officials read that as a sign that the islands have new negotiating power.

“These are matters of life and death for us,” said Ading, the Enewetak senator. “We can’t afford to rely exclusively on reassurances from one source. We need neutral experts from the international community to weigh in, to confirm or challenge” previous U.S. findings.

Many Marshallese say they don’t want U.S. money or apologies, but just a home in the Marshall Islands that is safe and secure.

Nerje Joseph holds out hope for a day when her children, grandchildren and great-grandchildren can return to her ancestral home in Rongelap and she can be buried in the sands of her youth, alongside her ancestors, under the coconut trees she remembers so well.

“In Los Angeles, you make movies about the Titanic. About people who lost everything,” she said.

“Why don’t you make movies about us?”

https://www.latimes.com/projects/marshall-islands-nuclear-testing-sea-level-rise/?utm_source=Nature+Briefing&utm_campaign=afb6bb4ab4-briefing-dy-20191111&utm_medium=email&utm_term=0_c9dfd39373-afb6bb4ab4-44039353

Every beachgoer can spot seaweed in the ocean or piling up on the beach, but Florida State University researchers working with colleagues in the United Kingdom have found that these slimy macroalgae play an important role in permanently removing carbon dioxide from the atmosphere.

Their work is published in the journal Ecological Monographs by the Ecological Society of America.

The researchers, who partnered with ecologists from Plymouth Marine Laboratory in the United Kingdom, investigated how seaweed absorbed carbon and processed it, trapping it in the seafloor.

“Seaweeds have been ignored in the ‘blue carbon’ storage literature in favor of seagrasses and mangroves, which physically trap carbon from sediments and their own biomass in root structures,” said Assistant Professor of Biological Science Sophie McCoy. “Macroalgae are also often overlooked by oceanographers who study the carbon cycle, as their high productivity occurs close to shore and has been thought to stay and cycle locally.”

In designing the study, researchers suspected that the high productivity and huge amount of seasonal biomass of annual algae would provide carbon subsidies farther offshore than typically considered, and that these subsidies would be important to benthic food webs there.

That was exactly what they found. They also discovered that this was the process that leads to the burial of seaweed carbon in ocean sediments.

Blue carbon is the carbon captured in marine systems both through photosynthesis and then by trapping it in the seafloor. Researchers sequenced environmental DNA and modeled stable isotope data for over a year off the coast of Plymouth, England. Through this, they found that seaweed debris was an important part of the food web for marine organisms and that much of that debris was ultimately stored in sediments or entered the food web on the seafloor.

Jeroen Ingels, a researcher at the FSU Coastal and Marine Laboratory who conducted the meiofauna work for the study, said the research not only explains seaweed’s role in the food web, but it also shows that human activities that affect seaweed and the sea floor are important to monitor.

“The human activities that are impacting macroalgae and sediment habitats and their interstitial animals are undermining the potential for these systems to mitigate climate change by affecting their potential to take up and cycle carbon,” he said. “The study really illustrates in a new way how seaweed and subsequently benthic animals can contribute in a significant way to blue carbon.”

The team found that about 8.75 grams of macroalgae carbon are trapped per square meter of sediment each year.

Ana M. Queiros, a scientist at Plymouth Marine Laboratory and the paper’s lead author, said these first measurements of seaweed carbon trapped in the sediment gives scientists more information to help them develop sustainable environmental practices.

“They tell us that the global extent of blue carbon-meaningful marine habitats could be much wider than we previously thought,” she said. “Identifying these areas and promoting their management will let us capitalize on the full potential of the ocean’s blue carbon towards the stabilization of the global climate system.”

Journal Reference:

Ana Moura Queirós, Nicholas Stephens, Stephen Widdicombe, Karen Tait, Sophie J. McCoy, Jeroen Ingels, Saskia Rühl, Ruth Airs, Amanda Beesley, Giorgia Carnovale, Pierre Cazenave, Sarah Dashfield, Er Hua, Mark Jones, Penelope Lindeque, Caroline L. McNeill, Joana Nunes, Helen Parry, Christine Pascoe, Claire Widdicombe, Tim Smyth, Angus Atkinson, Dorte Krause‐Jensen, Paul J. Somerfield. Connected macroalgal‐sediment systems: blue carbon and food webs in the deep coastal ocean. Ecological Monographs, 2019; e01366 DOI: 10.1002/ecm.1366

https://www.sciencedaily.com/releases/2019/06/190603124721.htm

Thanks to Lynn and Bill Penland for bringing this to the It’s Interesting community.

by Quirin Schiermeier

Efforts to curb greenhouse-gas emissions and the impacts of global warming will fall significantly short without drastic changes in global land use, agriculture and human diets, leading researchers warn in a high-level report commissioned by the United Nations.

The special report on climate change and land by the Intergovernmental Panel on Climate Change (IPCC) describes plant-based diets as a major opportunity for mitigating and adapting to climate change ― and includes a policy recommendation to reduce meat consumption.

On 8 August, the IPCC released a summary of the report, which is designed to inform upcoming climate negotiations amid the worsening global climate crisis. More than 100 experts, around half of whom hail from developing countries, worked to compile the report in recent months.

“We don’t want to tell people what to eat,” says Hans-Otto Pörtner, an ecologist who co-chairs the IPCC’s working group on impacts, adaptation and vulnerability. “But it would indeed be beneficial, for both climate and human health, if people in many rich countries consumed less meat, and if politics would create appropriate incentives to that effect.”

Deforestation concerns
Researchers also note the relevance of the report to tropical rainforests, with concerns mounting about accelerating rates of deforestation. The Amazon rainforest is a huge carbon sink that acts to cool global temperature, but rates of deforestation are rising, in part because of the policies and actions of the government of Brazilian President Jair Bolsonaro.

Unless stopped, deforestation could turn much of the remaining Amazon forests into a degraded type of desert, and could release more than 50 billion tonnes of carbon into the atmosphere in 30 to 50 years, says Carlos Nobre, a climate scientist at the University of São Paolo in Brazil. “That’s very worrying,” he says.

“Unfortunately, some countries don’t seem to understand the dire need of stopping deforestation in the tropics,” says Pörtner. “We cannot force any government to interfere. But we hope that our report will sufficiently influence public opinion to that effect.”

Paris goals
Although the burning of fossil fuels for energy and transport garners the most attention, activities relating to land management, including agriculture and forestry, produce almost one-quarter of heat-trapping gases resulting from human activities. The race to limit global warming to 1.5°C above pre-industrial levels ― the goal of the international Paris climate agreement made in 2015 ― might be a lost cause unless land is used in a more sustainable and climate-friendly way, the latest IPCC report says.

The report highlights the need to preserve and restore forests, which soak up carbon from the air, and peatlands, which release carbon if dug up. Cattle raised on pastures created by clearing woodland are particularly emission-intensive. This practice often comes with large-scale deforestation, as seen in Brazil and Colombia. Cows also produce large amounts of methane, a potent greenhouse gas, as they digest their food.

The report states with high confidence that balanced diets featuring plant-based and sustainably produced animal-sourced food “present major opportunities for adaptation and mitigation while generating significant co-benefits in terms of human health”.

By 2050, dietary changes could free up several million square kilometres of land, and reduce global CO2 emissions by up to eight billion tonnes per year, relative to business as usual, the scientists estimate (see ‘What if people ate less meat?’).

“It’s really exciting that the IPCC is getting such a strong message across,” says Ruth Richardson in Toronto, Canada, the executive director at the Global Alliance for the Future of Food, a strategic coalition of philanthropic foundations. “We need a radical transformation, not incremental shifts, towards a global land-use and food system that serves our climate needs.”

Careful management
The report cautions that land must remain productive to feed a growing world population. Warming enhances plant growth in some regions, but in others ― including northern Eurasia, parts of North America, Central Asia and tropical Africa ― increasing water stress seems to reduce vegetation. So the use of biofuel crops and the creation of new forests ― seen as measures with the potential to mitigate global warming ― must be carefully managed to avoid the risk of food shortages and biodiversity loss, the report says.

Farmers and communities around the world must also grapple with more intense rainfall, floods and droughts resulting from climate change, warns the IPCC. Land degradation and expanding deserts threaten to affect food security, increase poverty and drive migration.

About one-quarter of Earth’s ice-free land area seems to be suffering from human-induced soil degradation already ― and climate change is expected to make thing worse, particularly in low-lying coastal areas, river deltas, drylands and permafrost areas. Sea-level rise is also adding to coastal erosion in some regions, the report says.

Industrialized farming practices are responsible for much of the observed soil erosion, and for soil pollution, says André Laperrière, the executive director of Global Open Data for Agriculture and Nutrition in Wallingford, UK, an initiative that aims to make relevant scientific information accessible worldwide.

The report might provide a much-needed, authoritative call to action, he says. “The biggest hurdle we face is to try and teach about half a billion farmers globally to re-work their agricultural model to be carbon sensitive.”

Nobre also hopes that the IPCC’s voice will give greater prominence to land-use issues in upcoming climate talks. “I think that the policy implications of the report will be positive in terms of pushing all tropical countries to aim at reducing deforestation rates,” he says.

Regular assessments
Since 1990, the IPCC has regularly assessed the scientific literature, producing comprehensive reports every six years or so, and special reports ― such as today’s ― on specific aspects of climate change, at irregular intervals.

A special report released last year concluded that global greenhouse-gas emissions, which hit an all-time high of more than 37 billion tonnes in 2018, must decline sharply in the very near future to limit global warming to within 1.5°C of pre-industrial levels ― and that this will require drastic action without further delay. The IPCC’s next special report, about the ocean and ice sheets in a changing climate, is due next month.

Governments from around the world will consider the IPCC’s latest findings at a UN climate summit next month in New York. The next round of climate talks of parties to the Paris agreement will then take place in December in Santiago.

António Guterres, the UN secretary-general, said last week that it is “absolutely essential” to implement that landmark agreement ― and “to do so with an enhanced ambition”.

“We need to mainstream climate-change risks across all decisions,” he said. “That is why I am telling leaders don’t come to the summit with beautiful speeches.”

Nature 572, 291-292 (2019)

doi: 10.1038/d41586-019-02409-7

https://www.nature.com/articles/d41586-019-02409-7?utm_source=Nature+Briefing&utm_campaign=8838a84803-briefing-dy-20190819&utm_medium=email&utm_term=0_c9dfd39373-8838a84803-44039353


Frank Keutsch, Zhen Dai and David Keith (left to right) in Keutsch’s laboratory at Harvard University.

Zhen Dai holds up a small glass tube coated with a white powder: calcium carbonate, a ubiquitous compound used in everything from paper and cement to toothpaste and cake mixes. Plop a tablet of it into water, and the result is a fizzy antacid that calms the stomach. The question for Dai, a doctoral candidate at Harvard University in Cambridge, Massachusetts, and her colleagues is whether this innocuous substance could also help humanity to relieve the ultimate case of indigestion: global warming caused by greenhouse-gas pollution.

The idea is simple: spray a bunch of particles into the stratosphere, and they will cool the planet by reflecting some of the Sun’s rays back into space. Scientists have already witnessed the principle in action. When Mount Pinatubo erupted in the Philippines in 1991, it injected an estimated 20 million tonnes of sulfur dioxide into the stratosphere — the atmospheric layer that stretches from about 10 to 50 kilometres above Earth’s surface. The eruption created a haze of sulfate particles that cooled the planet by around 0.5 °C. For about 18 months, Earth’s average temperature returned to what it was before the arrival of the steam engine.

The idea that humans might turn down Earth’s thermostat by similar, artificial means is several decades old. It fits into a broader class of planet-cooling schemes known as geoengineering that have long generated intense debate and, in some cases, fear.

Researchers have largely restricted their work on such tactics to computer models. Among the concerns is that dimming the Sun could backfire, or at least strongly disadvantage some areas of the world by, for example, robbing crops of sunlight and shifting rain patterns.

But as emissions continue to rise and climate projections remain dire, conversations about geoengineering research are starting to gain more traction among scientists, policymakers and some environmentalists. That’s because many researchers have come to the alarming conclusion that the only way to prevent the severe impacts of global warming will be either to suck massive amounts of carbon dioxide out of the atmosphere or to cool the planet artificially. Or, perhaps more likely, both.

If all goes as planned, the Harvard team will be the first in the world to move solar geoengineering out of the lab and into the stratosphere, with a project called the Stratospheric Controlled Perturbation Experiment (SCoPEx). The first phase — a US$3-million test involving two flights of a steerable balloon 20 kilometres above the southwest United States — could launch as early as the first half of 2019. Once in place, the experiment would release small plumes of calcium carbonate, each of around 100 grams, roughly equivalent to the amount found in an average bottle of off-the-shelf antacid. The balloon would then turn around to observe how the particles disperse.

The test itself is extremely modest. Dai, whose doctoral work over the past four years has involved building a tabletop device to simulate and measure chemical reactions in the stratosphere in advance of the experiment, does not stress about concerns over such research. “I’m studying a chemical substance,” she says. “It’s not like it’s a nuclear bomb.”

Nevertheless, the experiment will be the first to fly under the banner of solar geoengineering. And so it is under intense scrutiny, including from some environmental groups, who say such efforts are a dangerous distraction from addressing the only permanent solution to climate change: reducing greenhouse-gas emissions. The scientific outcome of SCoPEx doesn’t really matter, says Jim Thomas, co-executive director of the ETC Group, an environmental advocacy organization in Val-David, near Montreal, Canada, that opposes geoengineering: “This is as much an experiment in changing social norms and crossing a line as it is a science experiment.”

Aware of this attention, the team is moving slowly and is working to set up clear oversight for the experiment, in the form of an external advisory committee to review the project. Some say that such a framework, which could pave the way for future experiments, is even more important than the results of this one test. “SCoPEx is the first out of the gate, and it is triggering an important conversation about what independent guidance, advice and oversight should look like,” says Peter Frumhoff, chief climate scientist at the Union of Concerned Scientists in Cambridge, Massachusetts, and a member of an independent panel that has been charged with selecting the head of the advisory committee. “Getting it done right is far more important than getting it done quickly.”

Joining forces
In many ways, the stratosphere is an ideal place to try to make the atmosphere more reflective. Small particles injected there can spread around the globe and stay aloft for two years or more. If placed strategically and regularly in both hemispheres, they could create a relatively uniform blanket that would shield the entire planet (see ‘Global intervention’). The process does not have to be wildly expensive; in a report last month, the Intergovernmental Panel on Climate Change suggested that a fleet of high-flying aircraft could deposit enough sulfur to offset roughly 1.5 °C of warming for around $1 billion to $10 billion per year1.

Most of the solar geoengineering research so far has focused on sulfur dioxide, the same substance released by Mount Pinatubo. But sulfur might not be the best candidate. In addition to cooling the planet, the aerosols generated in that eruption sped up the rate at which chlorofluorocarbons deplete the ozone layer, which shields the planet from the Sun’s harmful ultraviolet radiation. Sulfate aerosols are also warmed by the Sun, enough to potentially affect the movement of moisture and even alter the jet stream. “There are all of these downstream effects that we don’t fully understand,” says Frank Keutsch, an atmospheric chemist at Harvard and SCoPEx’s principal investigator.

The SCoPEx team’s initial stratospheric experiments will focus on calcium carbonate, which is expected to absorb less heat than sulfates and to have less impact on ozone. But textbook answers — and even Dai’s tabletop device — can’t capture the full picture. “We actually don’t know what it would do, because it doesn’t exist in the stratosphere,” Keutsch says. “That sets up a red flag.”

SCoPEx aims to gather real-world data to sort this out. The experiment began as a partnership between atmospheric chemist James Anderson of Harvard and experimental physicist David Keith, who moved to the university in 2011. Keith has been investigating a variety of geoengineering options off and on for more than 25 years. In 2009, while at the University of Calgary in Canada, he founded the company Carbon Engineering, in Squamish, which is working to commercialize technology to remove carbon dioxide from the atmosphere. After joining Harvard, Keith used research funding he had received from Microsoft co-founder Bill Gates, to begin planning the experiment.

Keutsch, who got involved later, is not a climate scientist and is at best a reluctant geoengineer. But he worries about where humanity is heading, and what that means for his children’s future. When he saw Keith talk about the SCoPEx idea at a conference after starting at Harvard in 2015, he says his initial reaction was that the idea was “totally insane”. Then he decided it was time to engage. “I asked myself, an atmospheric chemist, what can I do?” He joined forces with Keith and Anderson, and has since taken the lead on the experimental work.

An eye on the sky
Already, SCoPEx has moved farther along than earlier solar geoengineering efforts. The UK Stratospheric Particle Injection for Climate Engineering experiment, which sought to spray water 1 kilometre into the atmosphere, was cancelled in 2012 in part because scientists had applied for patents on an apparatus that could ultimately affect every human on the planet. (Keith says there will be no patents on any technologies involved in the SCoPEx project.) And US researchers with the Marine Cloud Brightening Project, which aims to spray saltwater droplets into the lower atmosphere to increase the reflectivity of ocean clouds, have been trying to raise money for the project for nearly a decade.

Although SCoPEx could be the first solar geoengineering experiment to fly, Keith says other projects that have not branded themselves as such have already provided useful data. In 2011, for example, the Eastern Pacific Emitted Aerosol Cloud Experiment pumped smoke into the lower atmosphere to mimic pollution from ships, which can cause clouds to brighten by capturing more water vapour. The test was used to study the effect on marine clouds, but the results had a direct bearing on geoengineering science: the brighter clouds produced a cooling effect 50 times greater than the warming effect of the carbon emissions from the researchers’ ship2.

Keith says that the Harvard team has yet to encounter public protests or any direct opposition — aside from the occasional conspiracy theorist. The challenge facing researchers, he says, stems more from a fear among science-funding agencies that investing in geoengineering will lead to protests by environmentalists.

To help advance the field, Keith set a goal in 2016 of raising $20 million to support a formal research programme that would cover not just the experimental work, but also research into modelling, governance and ethics. He has raised around $12 million so far, mostly from philanthropic sources such as Gates; the pot provides funding to dozens of people, largely on a part-time basis.

Keith and Keutsch also want an external advisory committee to review SCoPEx before it flies. The committee, which is still to be selected, will report to the dean of engineering and the vice-provost for research at Harvard. “We see this as part of a process to build broader support for research on this topic,” Keith says.

Keutsch is looking forward to having the guidance of an external group, and hopes that it can provide clarity on how tests such as his should proceed. “This is a much more politically challenging experiment than I had anticipated,” he says. “I was a little naive.”

SCoPEx faces technical challenges, too. It must spray particles of the right size: the team calculates that those with a diameter of about 0.5 micrometres should disperse and reflect sunlight well. The balloon must also be able to reverse its course in the thin air so that it can pass through its own wake. Assuming the team is able to find the calcium carbonate plume — and there is no guarantee that they can — SCoPEx needs instruments that can analyse the particles and, it is hoped, carry samples back to Earth.

“It’s going to be a hard experiment, and it may not work,” says David Fahey, an atmospheric scientist at the National Oceanic and Atmospheric Administration in Boulder, Colorado. In the hope that it will, Fahey’s team has provided SCoPEx with a lightweight instrument that can reliably measure the size and number of particles that are released. The balloon will also be equipped with a laser device that can monitor the plume from afar. Other equipment that could collect information on the level of moisture and ozone in the stratosphere could fly on the balloon as well.

Up to the stratosphere
Keutsch and Keith are still working out some of the technical details. Plans with one balloon company fell through, so they are now working with a second. And an independent team of engineers in California is working on options for the sprayer. To simplify things, the SCoPEx group plans to fly the balloon during the spring or autumn, when stratospheric winds shift direction and — for a brief period — calm down, which will make it easier to track the plume.

For all of these reasons, Keutsch characterizes the first flight as an engineering test, mainly intended to demonstrate that everything works as it should. The team is ready to spray calcium carbonate particles, but could instead use salt water to test the sprayer if the advisory committee objects.

Keith still thinks that sulfate aerosols might ultimately be the best choice for solar geoengineering, if only because there has been more research about their impact. He says that the possibility of sulfates enhancing ozone depletion should become less of a concern in the future, as efforts to restore the ozone layer through pollutant reductions continue. Nevertheless, his main hope is to establish an experimental programme in which scientists can explore different aspects of solar geoengineering.

There are a lot of outstanding questions. Some researchers have suggested that solar geoengineering could alter precipitation patterns and even lead to more droughts in some regions. Others warn that one of the possible benefits of solar geoengineering — maintaining crop yields by protecting them from heat stress — might not come to pass. In a study published in August, researchers found that yields of maize (corn), soya, rice and wheat3 fell after two volcanic eruptions, Mount Pinatubo in 1991 and El Chichón in Mexico in 1982, dimmed the skies. Such reductions could be enough to cancel out any potential gains in the future.

Keith says the science so far suggests that the benefits could well outweigh the potential negative consequences, particularly compared with a world in which warming goes unchecked. The commonly cited drawback is that shielding the Sun doesn’t affect emissions, so greenhouse-gas levels would continue to rise and the ocean would grow even more acidic. But he suggests that solar geoengineering could reduce the amount of carbon that would otherwise end up in the atmosphere, including by minimizing the loss of permafrost, promoting forest growth and reducing the need to cool buildings. In an as-yet-unpublished analysis of precipitation and temperature extremes using a high-resolution climate model, Keith and others found that nearly all regions of the world would benefit from a moderate solar geoengineering programme. “Despite all of the concerns, we can’t find any areas that would be definitely worse off,” he says. “If solar geoengineering is as good as what is shown in these models, it would be crazy not to take it seriously.”

There is still widespread uncertainty about the state of the science and the assumptions in the models — including the idea that humanity could come together to establish, maintain and then eventually dismantle a well-designed geoengineering programme while tackling the underlying problem of emissions. Still, prominent organizations, including the UK Royal Society and the US National Academies of Sciences, Engineering, and Medicine, have called for more research. In October, the academies launched a project that will attempt to provide a blueprint for such a programme.

Some organizations are already trying to promote discussions among policymakers and government officials at the international level. The Solar Radiation Management Governance Initiative is holding workshops across the global south, for instance. And Janos Pasztor, who handled climate issues under former UN secretary-general Ban Ki-moon, has been talking to high-level government officials around the world in his role as head of the Carnegie Climate Geoengineering Governance Initiative, a non-profit organization based in New York. “Governments need to engage in this discussion and to understand these issues,” Pasztor says. “They need to understand the risks — not just the risks of doing it, but also the risks of not understanding and not knowing.”

One concern is that governments might one day panic over the consequences of global warming and rush forward with a haphazard solar-geoengineering programme, a distinct possibility given that the costs are cheap enough that many countries, and perhaps even a few individuals, could probably afford to go it alone. These and other questions arose earlier this month in Quito, Ecuador, at the annual summit of the Montreal Protocol, which governs chemicals that damage the stratospheric ozone layer. Several countries called for a scientific assessment of the potential effects that solar geoengineering could have on the ozone layer, and on the stratosphere more broadly.

If the world gets serious about geoengineering, Fahey says that there are plenty of sophisticated experiments that researchers could do using satellites and high-flying aircraft. But for now, he says, SCoPEx will be valuable — if only because it pushes the conversation forward. “Not talking about geoengineering is the greatest mistake we can make right now.”

Nature 563, 613-615 (2018)

doi: 10.1038/d41586-018-07533-4

By Adam Vaughan

Pumping colossal amounts of ocean water onto the West Antarctic ice sheet could stop it collapsing and causing drastic sea level rise that would threaten cities including Tokyo and New York.

But the German and US researchers who have explored the idea admit the drastic intervention would require an “unprecedented effort for humankind in one of the harshest environments of the planet”. The fix would also be extremely expensive, incredibly hard to do and risk potentially devastating impacts for the region’s unique ecosystem.

Five years ago, studies suggested the West Antarctic ice sheet had already started an unstoppable collapse. While the process will take centuries, it would raise sea levels to a height that would have dire consequences for major coastal cities.

Bold ideas
The threat is so grave, it requires an exploration and discussion of bold ideas to stop the ice sheet’s collapse, says Anders Levermann of the Potsdam Institute in Germany. “I’m certain the impact is so big it justifies this sort of thinking. It doesn’t mean it justifies the measure,” he says.

Previous far-out ideas to stop the loss of the ice sheet have included building an island to stop the flow off the ice shelf. Levermann and colleagues instead modelled a more direct approach that would involve pumping ocean water onto the sheet, adding it either in liquid form or as snow. They found stabilising the collapse would require at least 7400 gigatonnes of the stuff over 10 years. “It’s a lot of ice. It’s huge,” says Levermann. He says while he is against global scale geoengineering proposals such as giant sunshades, the water pumping idea is different and more surgical.

Even if society agreed on such a scheme, it faces mind-boggling obstacles. Around 145GW of wind farm capacity would be needed for the pumping, 12 times that installed in Europe last year. Temperatures would be too low for existing turbines, so new materials would be needed. The infrastructure would also turn the region into an “industrial compound”, says Levermann. Costs would likely be hundreds of billions of dollars, he adds.

Not going to happen
“This publication gives an indication of quite how challenging it would be to attempt to halt ice sheet collapse through direct human intervention,” says Emily Shuckburgh at the University of Cambridge.

Clive Hamilton at Charles Sturt University in Australia says: “The conditions under which such a scheme could be implemented are beyond anything feasible. It’s not going to happen.”

The priority for limiting sea level rises remains cutting greenhouse gas emissions, Levermann emphasises. Shuckburgh says the paper underlines the best option of managing the risk from Antarctica is to rapidly reduce emissions.

Journal reference: Science Advances, DOI: 10.1126/sciadv.aaw4132

https://www.newscientist.com/article/2210043-a-drastic-plan-might-prevent-catastrophic-antarctic-ice-sheet-collapse/


A Soviet cow-fattening complex pictured in 1982.Credit: Nikolai Akimov/TASS

by Quirin Schiermeier

The collapse of the Soviet Union in 1991 led to a huge drop in greenhouse-gas emissions because the resulting economic crisis meant many people stopped eating meat.

Meat from domestic livestock farming was a main food staple during communist rule in the region. In 1990, Soviet citizens each consumed an average 32 kilograms of beef a year — 27% more than Western Europeans and four times more than the global average at the time.

But meat demand and livestock production in the region fell drastically when the prices of everyday consumer products soared and the purchasing power of the rouble dwindled in the post-communist economic crisis. An estimated one-third of late-Soviet cropland has been abandoned since.

These changes in the food and agriculture system in the former Soviet nations resulted in a net reduction of 7.6 billion tonnes of greenhouse gases in carbon dioxide equivalent from 1992 to 2011, researchers find from an analysis of data on livestock consumption and international trade1 (see ‘Soviet shocks’). The drop is equivalent to one-quarter of CO2 emissions from Amazon deforestation over the same period. Russia currently emits about 2.5 billion tonnes of greenhouse gases (CO2 equivalent) per year.

The figure considers emissions that result from domestic production of livestock and imported livestock, as well as carbon locked in soils and plants on abandoned Soviet cropland.

“There was a large drop in industrial production and emissions after the collapse of the Soviet Union, so it should be no surprise the same happened with food consumption and production,” says Glen Peters, a carbon-budget specialist at the Center for International Climate Research in Oslo, who was not involved in the analysis. “The study highlights the potential for carbon uptake in the former Soviet Union but also the risks to that carbon being released if agricultural production returns.”

Today, animal agriculture is responsible for 14.5% of human-caused greenhouse-gas emissions globally. Beef is the most emissions-intensive food because pastures are often created by clearing forests and savannahs.

Meat consumption — especially beef — and land-use changes in Russia and central Asia are a widely overlooked factor in calculations of greenhouse-gas emissions from land around the globe, says study author Florian Schierhorn at the Leibniz Institute of Agricultural Development in Transition Economies in Halle, Germany.

Trends in international trade suggest that emissions associated with meat consumption are on the rise again: Russia has over the past decade become a top destination for beef exported mainly from South America.

doi: 10.1038/d41586-019-02024-6

References
1. Schierhorn, F. et al. Environ. Res. Lett. 14, 065009 (2019).

https://www.nature.com/articles/d41586-019-02024-6?utm_source=Nature+Briefing&utm_campaign=34225bcef1-briefing-dy-20190701&utm_medium=email&utm_term=0_c9dfd39373-34225bcef1-44039353