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I'm interested in feedback on the posting policy. Geo list doesn't get anything like as much list posting as CDR does, because it's not as active a field. We can't do much about posting frequency directly, but we can change what's posted. Narrow posting policy means less list traffic. Personally, I didn't think this specific thread met the threshold for list posting, but there's always a degree of personal judgement. Andrew On Wed, 21 Dec 2022, 14:01 'Jessica Gurevitch' via geoengineering, < geoengineering@googlegroups.com> wrote: > Is there any way Ayesha could condense these stories with links, and post > once a week? I am really getting inundated by this constant stream of > emails. If everyone else is happy with the large number of emails posted by > Ayesha, that's obviously fine, but I may have to get off of this > listserve myself. > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > Jessica Gurevitch > Distinguished Professor and Co-Chair > Department of Ecology and Evolution > Stony Brook University > Stony Brook, NY 11794-5245 USA > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > On Wed, Dec 21, 2022 at 4:51 AM ayesha iqbal <ayeshaiqbal...@gmail.com> > wrote: > >> http://www.asee-prism.org/dimmer-switch/ >> *November 2022 *By Mark Matthews >> >> Aerospace engineer James T. Early built a 30-year career at the Lawrence >> Livermore National Laboratory working out big ideas. Among them: the use of >> pulsed lasers to knock space debris out of orbit, and a giant >> telescope—powerful enough to detect planets in distant solar systems—with >> lenses that roll up to fit inside a rocket and then spread out when >> launched in space. Trained at MIT, Caltech, and Stanford, Early drew >> inspiration from the science fiction of Isaac Asimov and Arthur C. Clarke. >> When his wife wanted to try her hand at the genre, he outlined a debut >> plot: terraforming Venus. An immense sun-blocking shield, he theorized, >> could cool the planet over time and turn its scorching, desiccated surface >> into a human habitat. >> >> Early wondered if a scaled-down sunshield could solve the real-life >> problem of a warming Earth caused by carbon-spewing power plants and >> vehicle exhaust. In three terse pages published in the *Journal of the >> British Interplanetary Society* in 1989, he spelled out a “conceptually >> simple method” for offsetting the heat-trapping greenhouse effect and >> cutting global temperatures by 2 degrees Celsius (3.6°F). A glass shield >> could be fabricated on the moon out of lunar soil and dispatched, using an >> electromagnetic accelerator, to the first Lagrange point (L1), a million >> miles from Earth, where the gravitational pull of the Earth and sun cancel >> each other out. He hazarded a price tag of $1 trillion to $10 >> trillion—“enormous,” yes, but perhaps much lower than the economic impact >> of the greenhouse effect. >> >> Roger Angel, an esteemed astronomer at the University of Arizona, built >> on Early’s idea in 2006. He conceived a giant space cloud at L1 comprising >> trillions of thin reflective satellites, each a meter wide and weighing 1 >> gram. These little “flyers” would be kept aligned with the sun by solar >> sails, which are powered by photons of sunlight bouncing off a mirrored >> surface. Manufactured on Earth, the satellites would be sent aloft to L1 in >> stacks of 800,000 using electromagnetic acceleration and ion propulsion. >> They would form a cloud some 60,000 miles long and 2,000 miles across, >> weighing 20 million tons. Angel’s detailed six-page description in the >> *Proceedings >> of the National Academy of Sciences* estimated a cost of “a few trillion >> dollars.” The idea, he wrote, might be desirable if “dangerous changes in >> global climate were inevitable.” >> >> Early and Angel were each ahead of their time in combining futuristic >> space technology with the science of preventing catastrophic climate >> change. But their vision of a vast sunshield looks a bit more realistic >> now, amid such advances as a fledgling space tourism industry, reusable >> rockets curbing the cost of space launches, and growing interest in >> space-based manufacturing and moon and asteroid mining. Meanwhile, as the >> effects of climate change become alarmingly clear and warnings by the >> Intergovernmental Panel on Climate Change grow more precise and ominous, a >> growing number of scientists, engineers, graduate students, and members of >> Congress are looking to geoengineering as a possible when-all-else-fails >> technical fix for an overheating planet. >> >> Enter Space Bubbles, a 2022 variation on the sunshield idea from a team >> of MIT engineers. Led by Carlo Ratti, director of the university’s >> Senseable City Lab, the group envisions giant space >> platforms—“rafts”—composed of stuck-together inflatable spheres of >> thin-film silicon or another molten material, positioned slightly closer to >> the sun than L1. The spheres would be manufactured using “space-based >> fabrication methods” not clearly defined. Like the Early and Angel >> concepts, the rafts would block 1.8 percent of the sun’s rays—an amount >> sufficient to prevent dangerous warming. The cooling could begin by the end >> of this century, “when the most severe consequences of climate change are >> currently predicted,” the team says. As to price, “Our initial estimations >> suggest that the Space Bubble Raft will have lower mass-density than Roger >> Angel’s proposal and might thus be more cost-efficient,” Ratti tells >> *Prism.* >> >> Space Bubbles brings a disruptive, Elon Musk-style audacity to >> geoengineering (also known as climate intervention) and to the small but >> prolific community of scientists and engineers who have spent years or even >> decades studying other climate-cooling methods that would operate much >> closer to the Earth’s surface. Members of this community would prefer that >> such methods never be necessary; almost in unison, they insist that >> geoengineering would not be a substitute for slashing greenhouse gas >> emissions. But they work with the intensity of people who view climate >> intervention as an essential hedge against disaster and want to ensure that >> its feasibility and risks are understood. As Douglas MacMartin, a Cornell >> University aerospace engineer and geoengineering researcher, explains, the >> goal is to “provide enough knowledge that the world . . . can make informed >> decisions about this” versus “knee-jerk” reactions such as “‘Oh, things are >> desperate. We need to go try something,’” or “‘Oh, that sounds like a bad >> idea. We shouldn’t do it.’” >> Policy Matters >> >> Increasingly, people in Washington agree. Citing “potentially >> catastrophic consequences” of global warming, a panel of the National >> Academies of Science, Engineering, and Medicine (NASEM) last year urged the >> federal government to establish, in coordination with other countries, a >> modest transdisciplinary research program on solar geoengineering (SG) that >> “attempts to moderate warming by increasing the amount of sunlight that the >> atmosphere reflects back to space or by reducing the trapping of outgoing >> thermal radiation.” The NASEM panel, which included MacMartin, said >> knowledge gained from the recommended research “will be critical for >> informing climate change response strategies, and evidence either in favor >> or disfavor of SG deployment could have profound value.” >> >> As NASEM issued its findings, Congress directed the White House Office of >> Science and Technology Policy (OSTP) to develop a working group among the >> non-defense federal science agencies to manage near-term climate hazard >> risk and coordinate climate intervention research. The working group >> “should also establish a research governance framework to provide guidance >> on transparency, engagement, and risk management for publicly funded work >> in solar geoengineering research,” appropriators said. >> >> A congressional mandate, participation of multiple federal agencies, and >> direction from the White House promise to elevate geoengineering from a >> controversial niche science to a mainstream research field relevant to >> policymakers. David Keith, a Harvard applied physicist and an influential >> proponent of geoengineering research, has been calling publicly for such a >> step since at least 2010. (See *Prism’s* October 2013 Up Close profile >> <https://www.asee-prism.org/up-close-oct-1/> and February 2019 cover >> story.) <https://www.asee-prism.org/polar-prospects/> Testifying that >> year before the House Science and Technology Committee, he likened >> geoengineering to chemotherapy as an undesirable but possibly necessary >> emergency measure. “We must hope for the best while laying plans to >> navigate the worst,” Keith told the lawmakers. >> >> Planning for “the worst” is shaping up as prudent strategy. The world has >> failed to keep pace with the cuts in greenhouse gas emissions required by >> the 2015 Paris agreement, which aims to cap the global temperature this >> century at well below 2 degrees Celsius above preindustrial levels and >> calls for progress toward a limit of 1.5 degrees Celsius (about 2.7° >> Fahrenheit). The $369 billion in US climate and clean energy programs >> contained in the recently enacted Inflation Reduction Act falls short in >> fulfilling the country’s pledge to slash emissions. Some provisions do win >> applause from experts, however. For instance, the new law’s measures to >> control methane, a super-potent greenhouse gas, are “very encouraging,” >> says Yangyang Xu, an assistant professor of atmospheric sciences at Texas >> A&M University. He adds: “The direct and heavy penalty imposed on future >> [methane] leakage, if done with careful monitoring and verification, is a >> game changer, and can serve as a model for limiting other non-CO₂ >> emissions.” >> Solar Systems >> >> A coordinated federal research effort on geoengineering has been a long >> time coming. As early as 1965, a study appended to a White House >> environmental report found that the warming effects of a carbon dioxide >> buildup “could be deleterious” for humanity and urged that “countervailing >> climatic changes” be thoroughly explored. Led by oceanographer Roger >> Revelle, then director of Harvard’s Center for Population Studies, the >> study suggested the Earth could be cooled by increasing the albedo, or >> reflectivity, of the earth’s surface. One way to do that, it said, would be >> to spread very small reflecting particles over large areas of the ocean. >> >> The recent NASEM panel called for government-backed research focused on >> three sunlight-blocking, or solar radiation modification (SRM), methods. >> The first, solar aerosol injection (SAI), involves discharging tiny >> particles into the stratosphere, an upper layer of the atmosphere between >> 10 and 50 kilometers (6 to 30 miles) above the Earth’s surface. The concept >> dates from work published in the mid-1970s by Soviet climatologist Mikhail >> Budyko. It gained credibility in a 2006 essay by Paul Crutzen, who shared >> the 1995 Nobel Prize in chemistry for discovering how pollutants in the >> atmosphere were destroying the ozone layer. SAI is widely considered the >> method most likely to work because nature has provided a proof of concept. >> Volcanic eruptions spew out huge amounts of ash containing sulfur dioxide. >> Lofted to the stratosphere, the sulfur dioxide reacts with water to form a >> layer of sulfuric acid droplets that reflect and diffuse incoming sunlight >> and radiant heat. When the Philippines’ Mount Pinatubo erupted in 1991, >> “stratospheric winds spread these aerosol particles around the globe,” >> resulting in “a measurable cooling of the Earth’s surface” for almost two >> years, NASA reported in 2001. >> >> A second SRM method, marine cloud brightening, entails spraying seawater >> into low-lying clouds above the ocean to make them more reflective. Cirrus >> cloud thinning—a third, less well studied form of cooling—would break up >> the delicate strands of ice-crystal clouds above 20,000 feet and let heat >> rising from the earth’s surface escape the atmosphere. SRM methods alarm >> many environmentalists, primarily for two reasons: 1) they don’t remove the >> root cause of climate change, namely the accumulation of greenhouse gases >> in the atmosphere and 2) they could ease pressure on societies and >> governments to keep cutting emissions. >> >> OSTP’s anticipated strategy won’t start from scratch; federal support for >> geoengineering research has occurred mostly under the radar but hasn’t been >> totally lacking. In 2020, Congress provided $4 million to the National >> Oceanic and Atmospheric Administration (NOAA) to initiate what the agency >> says is “much-needed ‘baseline’ research” on climate intervention >> proposals—particularly SAI. Congress upped funding this year to $9 million, >> instructing NOAA to expand its efforts and coordinate with NASA and the >> Department of Energy (DOE). >> >> Computer modeling has provided much of what is now known about >> geoengineering’s potential and risks. The Intergovernmental Panel on >> Climate Change draws from more than two dozen modeling centers for its >> climate assessments, but one of the most important is the National Center >> for Atmospheric Research (NCAR), sponsored by the National Science >> Foundation and headquartered in the Rocky Mountain foothills in Boulder, >> Colorado. In addition to providing vital data on the Earth’s climate and >> weather, NCAR also serves as a nerve center for geoengineering studies, >> enabling global academic collaboration on experiments using ever more >> advanced models and a high-performance computer in Cheyenne, Wyoming. >> Expect the Unexpected >> >> The teaming up of NOAA, NASA, and DOE will expand the tools available for >> researchers to observe the climate system—such as satellites, balloons, >> aircraft capable of reaching the lower stratosphere, and, soon, a >> next-generation NCAR supercomputer. The anticipated result: improved >> models. But a host of questions remain. “Every time we go up in the >> atmosphere and make measurements, we find things we didn’t expect, things >> we didn’t know we would see,” says Gregory Frost, a NOAA supervisory >> research chemist. >> >> For instance, scientists know that sulfur dioxide, injected into the >> stratosphere, will form aerosols and lower the Earth’s temperature >> temporarily—but that’s just a piece of the puzzle, notes NCAR senior >> scientist Simone Tilmes, a leader in solar geoengineering research. “We >> know we can cool, but we don’t know how much injection we actually need to >> cool. There’s still a huge uncertainty on how much you can cool with a >> certain amount of injection,” she explains. “We also need to understand the >> positive and negative consequences of a possible application [of SAI] and >> weigh risks and benefits before any of these [options] should be >> considered.” >> >> As Cornell’s MacMartin puts it, “A lot of the research to date has been >> kind of trying things: ‘Hey, we’ll go try this strategy, scenario, climate >> model, and we’ll see what happens.’” Over time, the discovery of negative >> side effects has prompted modelers to explore ways of tweaking, for >> instance, the degree of cooling achieved or location of aerosol injections. >> Eventually, MacMartin hopes, scientists will be able to say, “We’ve looked >> at the response in a number of different climate models . . . Here’s what >> we think will happen. And here’s how confident we are in that assessment.” >> >> MacMartin, Yale lecturer Wake Smith, and others recently studied the >> concept of deploying stratospheric aerosol injection only in subpolar >> regions. Such action wouldn’t cool the global climate, but it could halt or >> even reverse the melting of Arctic ice that now threatens to cause a >> substantial rise in sea levels, the scholars say. >> >> Live outdoor testing of SAI would buttress existing research with >> accurate observations, even if the testing doesn’t answer all the >> outstanding questions. But an attempt by Harvard researchers last year >> showed just how strong public opposition can be even to research on >> geoengineering. The team planned to send up a balloon to release a small >> quantity of aerosols into the stratosphere. Following years of preparation, >> funded in part by Bill Gates, the team explored various launch venues. >> Ultimately, it partnered with the Swedish Space Corporation and made plans >> to use its base near Kiruna, Sweden, above the Arctic Circle. The initial >> flight would merely test the equipment and not spray any aerosol. But the >> stratospheric controlled perturbation experiment (SCoPEx) drew strong local >> opposition and was put on hold. The indigenous Sámi people, whose ancestral >> homeland stretches across Arctic regions of Sweden, Norway, Finland, and >> Russia, joined with Swedish environmental groups to lobby against SCoPEX, >> citing “risks of catastrophic consequences, including the impact of >> uncontrolled termination, and irreversible sociopolitical effects.” >> Lists of Concerns >> >> “I think the political barriers might be much stronger than the technical >> barriers,” says Alan Robock, environmental science professor at Rutgers >> University. Renowned for projecting the human, climatic, and ecological >> consequences of nuclear war—“We have to solve the problem of nuclear >> weapons so we have the luxury of worrying about global warming,” he >> says—Robock also applies his forensic research skills to geoengineering. In >> 2008 he published “20 Reasons Why Geoengineering May be a Bad Idea.” His >> tally of “risks and concerns” has since grown to 28. For SAI, they include >> depletion of stratospheric ozone, which helps block harmful ultraviolet >> rays; increased ocean acidification; a greater likelihood of droughts in >> some parts of the world; the need to keep increasing SAI because existing >> particles will grow and become less effective; and the danger of a sudden >> warming spike if SAI were ever shut down. “It’s like pulling back on a >> spring,” Robock told *The Takeaway,* a public radio talk show. >> >> As concerns remain about SAI, another proposed method of solar >> modification, marine cloud brightening (MCB), engenders a fundamental >> question. That is, can you actually brighten clouds? “Clouds are a really >> complicated species,” says Robert Wood, a professor of atmospheric sciences >> at the University of Washington and principal investigator of a research >> collaboration on MCB. The brightening idea originated with British >> physicist John Latham, who proposed it two years after starting work on >> climate change at NCAR. >> >> Scientists know that clouds cool the earth’s surface and believe their >> reflectivity can be enhanced based on observations of cloud responses to >> aerosols emitted in ship exhaust. “Since preindustrial times, human >> activity has injected a lot of aerosols and they have exerted a cooling >> effect on the planet that partly offsets warming by greenhouse gases,” Wood >> says. “So we think it’s feasible.” But, he adds, “the clouds don’t always >> do things that you think they’re going to do.” Their internal dynamics are >> too fine-grained to show up in climate models. >> >> Testing of Latham’s theory has begun on Australia’s Great Barrier Reef, a >> World Heritage Site where climate change is killing coral. Wood’s team is >> planning tests using vessels that spray seawater into the air, forming >> particles of salt that would be lofted upward by warm air to low-lying >> clouds. Conducted over a limited area of the ocean, the tests would have >> minimal environmental impact but yield important information, the group >> says. Worldwide, however, MCB’s potential impact is unclear. According to a >> 2009 British modeling study, while MCB would slow the pace of global >> warming, it could also disrupt rainfall patterns. Some areas would likely >> get wetter, others drier—particularly the Amazon rain forest, “a major sink >> for carbon dioxide.” >> ‘Explore the Edges’ >> >> The notion of applying space technology to geoengineering has produced >> comparatively little research over the years, apart from the growing use of >> satellites for climate and atmospheric observations. Among those intrigued >> by James Early’s 1989 idea was Edward Teller, the Lawrence Livermore >> National Laboratory co-founder who was known as the father of the hydrogen >> bomb. In 1997, Teller published the idea of a space-based metallic shield >> to scatter sunlight. Another was Colin McInnes, now an aerospace >> engineering professor at the University of Glasgow, who read Early’s >> article as a PhD student. He went on to develop new approaches to a space >> shield, most recently in 2015. “It’s one of these ideas that sticks with >> you,” he tells *Prism.* McInnes went on to explore, with Cranford >> University colleague Joan-Pau Sánchez, a system of multiple mobile >> sunshades in space. This “optimal configuration” would both curb overall >> global warming and allow the system to adjust the sunshade effects for >> different latitudes and seasons, they wrote. >> >> McInnes participated in a 2019 Harvard meeting that looked seriously at >> various space-based geoengineering schemes. Meeting organizers concluded >> that the concept “is not a plausible near-term goal or aspiration.” Still, >> he sees value in the research: “What I think is interesting is that [with] >> these concepts, you can explore, if you like, the edges of a problem or >> where the boundaries might be. And that then gives you a better idea of >> where to look for solutions.” >> >> By not directly interfering in the Earth’s atmosphere, space-based >> sunshades “appear to be one of the most efficient methods to tackle climate >> change,” McInnes wrote in a paper coathored with Sánchez. The authors >> acknowledged that the project would be equivalent in scale to a Three >> Gorges Dam—China’s gigantic hydroelectric project—a million miles from >> earth and require the manufacture of reflective material equal to a >> decade’s worth of aluminum foil. >> >> The 2021 NASEM report didn’t mention a space-based sunshield among its >> recommended federal research topics—a sign that the panel concurs with >> Robock’s conclusion that it’s “too expensive, too technologically >> questionable.” Of Space Bubbles, Harvard’s Keith says Ratti’s team “has >> cool tech, but when I met with them, they did not articulate any sensible >> reason, other than just asserting it, why this would be a better pathway >> than the existing pathways.” The idea generated press, he asserts, “not >> because it’s important but because a story with MIT and space bubbles and >> geoengineering was just too sweet to pass up.” >> Work in Progress >> >> Ratti is indeed a newcomer to geoengineering. Until recently, Senseable >> City Lab has pursued climate adaptation and mitigation “by optimizing our >> built environments and transportation infrastructures,” he says. The >> website of his Turin, Italy-based architecture and engineering firm >> features two examples: a synergistic pairing of autonomous taxis and a new >> skyscraper in Singapore, and large thermal basins floating off Helsinki’s >> harbor that serve as hot-water batteries for the city’s heating systems. >> Now, Ratti says, “Earth-based climate solutions may not be enough, and more >> radical technologies might be needed to address the coming climate >> disaster.” >> >> While Space Bubbles is still a “working hypothesis,” Ratti’s team says it >> has simulated thin-film bubbles in outer space conditions and found they >> could prove effective at deflecting solar radiation. The spheres could be >> made of silicon-based melts or graphene-reinforced ionic liquids. Other >> potential composites will be explored. But the team’s concept paper omits >> details on how the bubble material reaches space, gets assembled, and is >> stabilized. >> >> The challenge of filling those gaps falls to Ratti and five MIT >> colleagues. Two members of the National Academy of Engineering—computer >> scientist and roboticist Daniela Rus, winner of a 2002 MacArthur “genius >> grant,” and Gareth McKinley, professor of teaching innovation in the >> Department of Mechanical Engineering—are joined by Charles Primmerman, a >> Lincoln Laboratory high-energy laser expert; materials scientist Markus >> Buehler, a specialist in bio-inspired design and in building materials atom >> by atom; and aerospace engineer Paulo Lozano, director of the MIT Space >> Propulsion Laboratory. Ratti says that “we expect other collaborators to >> join us at MIT and beyond.” >> >> With Space Bubbles, “we aim to develop a fully reversible space-based >> solution,” Rus tells *Prism.* MIT’s Computer Science and Artificial >> Intelligence Laboratory, which she directs, “will develop the robotic >> devices and AI systems that will help control the space bubbles.” >> >> If fabricating a vast sunshield at L1 still seems like performing the >> impossible, McInnes ticks off advances, like reusable vehicles, that are >> making space more accessible. >> >> “If we are able to get much better at space robotics—if we can extract >> materials from near-earth asteroids, for example—and if we develop >> technologies for manufacturing large structures in space, then you can >> imagine a future where all of those different technological strands . . . >> come together” to make what now seems like an enormous technical challenge >> potentially more feasible, says McInnes. There’s already strong interest in >> in-orbit manufacturing, he adds. >> Help Wanted >> >> The biggest hurdle McInnes sees to any kind of geoengineering >> (space-based or otherwise)—and the reason he is a skeptic about its >> implementation—is governance: “the regulatory challenges of getting >> international agreement.” Private groups are working on the problem. They >> include the Carnegie Climate Governance Initiative launched by the Carnegie >> Council for Ethics in International Affairs, which “seeks to catalyse the >> creation of effective governance for climate-altering technologies” and the >> Global Commission on Governing Risks from Climate Overshoot, formed to >> “recommend a strategy to reduce risks should global warming goals be >> exceeded.” So far, governments haven’t been publicly involved. >> >> Keith, an adviser to the Climate Overshoot Commission’s secretariat, says >> the United States and China loom large in any decision to deploy >> geoengineering. “If the US and China both clearly want it, then it happens. >> Conversely, if they both don’t want it, then it doesn’t.” If neither >> superpower stakes out a strong position, “it’s quite possible small >> countries could play a big role to determine what happens.” >> >> If the world fails to meet the challenge of climate change and approaches >> catastrophe, humanity might seek a fallback in aerospace engineer Early’s >> science fiction plot of some 33 years ago. Venus, anyone? >> >> *Source*: PRISM >> >> -- >> You received this message because you are subscribed to the Google Groups >> "geoengineering" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to geoengineering+unsubscr...@googlegroups.com. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/geoengineering/CAOyeF5tF40KDM_S45DjdoF61kc6QAm98MyCNOQE1r9rmM1m%2B7w%40mail.gmail.com >> <https://groups.google.com/d/msgid/geoengineering/CAOyeF5tF40KDM_S45DjdoF61kc6QAm98MyCNOQE1r9rmM1m%2B7w%40mail.gmail.com?utm_medium=email&utm_source=footer> >> . >> > -- > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to geoengineering+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/geoengineering/CA%2BPtSANLyR2wwED0v8vj7q01DoMmpeuo2S5HFmBrRLG25cp0jA%40mail.gmail.com > <https://groups.google.com/d/msgid/geoengineering/CA%2BPtSANLyR2wwED0v8vj7q01DoMmpeuo2S5HFmBrRLG25cp0jA%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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