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Solar Geoengineering (Tactics For Manipulating Solar Heating Of Earth)

An evil atmosphere is forming around geoengineering
http://www.newscientist.com/article/mg2 ... ering.html

Krakatoa - an inspiration for more than just art? (Image: Roger-Viollet/Rex Features)

IN 1892 Edvard Munch witnessed a blood-red sunset over Oslo, Norway. Shaken by it, he wrote in his diary that he felt "a great, unending scream piercing through nature". The incident inspired him to create his most famous painting, The Scream.

The striking sunset was probably caused by the eruption of Krakatoa, which sent a massive plume of ash and gas into the upper atmosphere, turning sunsets red around the globe and cooling the Earth by more than a degree.

Now a powerful group of scientists, venture capitalists and conservative think tanks is coalescing around the idea of reproducing this cooling effect by injecting sulphur dioxide into the stratosphere to counter climate change. Despite the enormity of what is being proposed - nothing less than seizing control of the climate - the public has been almost entirely excluded from the planning.

Up to now, governments have been reluctant to talk about geoengineering. The reason is simple: apart from its unknown side effects, it would weaken resolve to reduce emissions.

But it may soon prove an irresistible fix. This form of geoengineering is extremely attractive because its costs are estimated to be trivial compared to those of cutting carbon. It also gets powerful lobbies off governments' backs, gives the green light to burning more coal, avoids the need to raise petrol taxes, permits yet more unrestrained growth and is no threat to consumer lifestyles.

No government is yet willing to lend support to geoengineering, but the day when a major nation backs it cannot be far off. It is even possible that a single nation suffering the effects of climate disruption may decide to act alone.

Indeed, Russia has already begun testing. Yuri Izrael, a scientist who is both a global-warming sceptic and a senior adviser to Prime Minister Putin, has tested the effects of aerosol spraying from a helicopter. He now plans a large-scale trial.

Izrael is the latest in a long line of scientists who have advocated planetary engineering. Two of the earliest and most aggressive were Edward Teller and Lowell Wood. Teller, who died in 2003, is often described as the "father of the hydrogen bomb" and was the inspiration for Dr Strangelove, the eponymous mad scientist of Stanley Kubrick's 1964 film. Wood was one of the Pentagon's foremost weaponeers, which led his critics to dub him "Dr Evil". He led Ronald Reagan's ill-fated Star Wars project.

Wood and Teller began promoting aerosol spraying in 1998. Reflecting the dominant opinion of the 1950s, they saw it as our duty to exert supremacy over nature. Both have long been associated with conservative think tanks that deny the existence of human-induced global warming.

A number of right-wing think tanks actively denying climate change are also promoting geoengineering, an irony that seems to escape them.

Of course, geoengineering protects their funders in the fossil fuel industries because it can be a substitute for carbon reductions and justify delay, but a deeper explanation lies in beliefs about the relationship of humans to the natural world.

While emissions reductions are an admission that industrial society has harmed nature, engineering the climate would be confirmation of our mastery over it, final proof that human ingenuity will always triumph.

Wood believes that climate engineering is inevitable. In a statement that could serve as Earth's epitaph, he declared: "We've engineered every other environment we live in, why not the planet?"

Advocates of geoengineering also court the super-rich. Wood is doubtful that governments can reach a consensus, but he sees no need for that, instead speculating about going ahead with support from a billionaire. "As far as I can determine, there is no law that prohibits doing something like this". He is right.

Perhaps the billionaire he has in mind is Bill Gates, who has been funding geoengineering research for three years. Gates is also an investor in a firm named Intellectual Ventures that is promoting a scheme called StratoShield, which would pump sulphur dioxide into the upper atmosphere through a hose held aloft by blimps.

Richard Branson has also set up his own "war room" to do battle with global warming using "market-driven solutions", including geoengineering.

The Carbon War Room website promotes a paper co-authored by Lee Lane of the American Enterprise Institute, well known for its climate scepticism. It argues that the benefits of geoengineering vastly outweigh the costs. The authors worry that ethical objections from environmental groups may block deployment, before noting with relief that "in reality, important economies remain largely beyond the influence of environmental advocacy groups".

Geoengineering is not something we should enter into lightly or without proper public consultation. If we resort to it, then the concentration of carbon dioxide will continue to rise. It would then become impossible to call a halt to sulphur injections, even for a year or two, without an immediate jump in temperature.

It's estimated that if whoever controls the scheme decided to stop, the greenhouse gases that would have built up could cause warming to rebound at a rate 10 to 20 times that of the recent past - a phenomenon referred to, apparently without irony, as the "termination problem". Once we start engineering the atmosphere we could be trapped, forever dependent on sulphur injections. More than a painting, The Scream would become a prophecy.
If we start manipulating the atmosphere, we could become forever dependent on sulphur injections

Clive Hamilton is Charles Sturt Professor of Public Ethics in the Centre for Applied Philosophy and Public Ethics at the Australian National University. His new book, Requiem for a Species, is published by Earthscan
 
Geoengineering. What could possibly go wrong?
 
Geoengineering won't curb sea-level rise
http://www.nature.com/news/2010/100823/ ... 0.426.html
Space mirrors and 'volcanic' blasts are not an easy fix for the rise in sea levels.

Richard Lovett

space mirrorClimate engineering methods such as space mirrors in Earth orbit would fail to work in isolation.VICTOR HABBICK VISIONS/SCIENCE PHOTO LIBRARY

Unless they involve extreme measures, geoengineering approaches to offset the effects of human-driven climate changes won't do much to combat rising sea levels, an international team of scientists reports in the Proceedings of the National Academy of Sciences1.

That is because sea levels respond slowly to changes in Earth's temperature, says John Moore, a palaeoclimatologist at Beijing Normal University and lead author of the study.

"We've got this 150-year legacy of fossil-fuel [burning], land-use changes, et cetera," he says. "You can't just slam on the brakes instantaneously."

Moore and his team examined two proposed geoengineering schemes: mirrors orbiting in space to reduce incoming sunlight, and sulphates being shot into the upper atmosphere to create a bright, sunlight-reflecting haze — similar to the one produced naturally by the 1991 eruption of Mount Pinatubo in the Philippines. Either scheme could reduce incoming solar energy by about 1–4 watts per square metre, enough to offset the atmospheric warming caused by carbon dioxide build-up until at least 2070.

To determine how this might affect sea levels, Moore and his group used a computer model that could track historical sea-level changes over the past 300 years. They found that under a business-as-usual fossil-fuel scenario, even the 4-watt space mirror reduced this century's sea-level rise by only some 39 centimetres out of a projected 'no-intervention' rise of about 1 metre.

Only in combination with fairly aggressive carbon dioxide emissions reductions, Moore and his team calculated, could these geoengineering schemes have a larger effect. Even then, they would not completely stop sea-level rise, with the oceans likely to be about 30 centimetres higher by 2100, depending on the emissions scenario.
Two and a half Pinatubos

To nip sea-level rise in the bud, the scientists calculated, would require either injections of sulphur dioxide aerosol into the stratosphere equivalent to more than 2.5 Pinatubo eruptions every four years, or a commitment to constructing an ever-expanding space mirror.

Another problem, Moore says, is that once started, geoengineering must be continued or temperatures will quickly rebound to what they would have been without intervention. An attendant surge in sea-level rise wouldn't occur quite as quickly, but it would follow soon enough, at a rate of up to 1–2 centimetres per year, he says.

"Those are speeds that were observed during the last deglaciation," says Moore, "so we're not forecasting anything that is out of the geological record."

The economic effects of that would be so extreme, he adds, that a cost-benefit analysis indicates that geoengineering isn't even worth considering if there is more than about a one-in-ten chance that it will be suddenly discontinued. "It's playing economic roulette."

Richard Alley, a glaciologist and climate researcher at Pennsylvania State University in Philadelphia, calls the findings a "nice advance". He notes, however, that it is only the beginning of trying to determine how glaciers might react to geoengineering.

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"We don't really have an ice-sheet model that we trust," says Alley, noting that, in addition to global warming, glaciers react to local and regional changes in winds, ocean temperatures and ocean circulation. "In many ways," he says, "this large advance serves to show how far we have to go before climate modelling of geoengineering is really good enough that useful regional projections could be made to guide decision-makers."

Alan Robock, a geophysicist from Rutgers University in New Jersey, agrees, but says that one finding that does come through strongly is that geoengineering has only a relatively minor effect on sea-level rise. "Reducing emissions of greenhouse gases will have a much larger impact," he says.

Moore concurs. "Anything that isn't reducing the amount of carbon dioxide in the atmosphere is like putting [on] a bandage rather than actually solving the problem," he says.

*
References
1. Moore, J. C., Jevrejeva, S. & Grinsted, A. Proc. Natl Acad. Sci. USA advance online publication doi:10.1073/pnas.1008153107 (2010).
 
Climate fix technical test put on hold

A pioneering test of a climate "tech fix" planned for October faces a six-month delay as scientists discuss the issues it raises with their critics.

The test is part of the UK-based Stratospheric Particle Injection for Climate Engineering (Spice) project.

It would use a balloon and a kilometre-long hose to spray water into the upper atmosphere - a prelude to spraying climate-cooling sulphate particles.

But the funders believe that more talks about the social aspects are needed.

The project is supported to the tune of £1.6m by UK research councils, including the Engineering and Physical Sciences Research Council (EPSRC), whose independent advisory panel recommended the delay last week.

The test would have put the UK at the forefront of practical climate engineering research.

Dr Matt Watson of the UK's Bristol University, who leads the overall project, said he endorsed the decision, although his team had been "taken aback" when they first heard the news.

"We're talking about a pressure washer you could buy in a hardware shop, a long hose, and two bathloads of water, so you couldn't have a more benign experiment," he told BBC News.

"But in the end it's the social context that's important - and we realise there's no point in having the (ESPRC independent panel) process unless we're going to work with it."

The initial deployment, due to take place from an abandoned airfield in Sculthorpe, Norfolk, will almost certainly not take place before April.

If and when it does happen, the balloon will be allowed to rise to an altitude of 1km, tethered to the ground with reinforced hosepipe.

The pressure washer will pump water from the ground and spray it from the end of the hosepipe. Researchers will use the set-up to investigate practicalities such as how the balloon and the pipe react to high winds.

A planned series of further trials is envisaged, eventually answering the question of whether it would ever be practical to put large quantities of sulphate aerosols into the stratosphere this way.

The principle behind the idea is that high-altitude aerosols would cool the planet's surface by reflecting solar energy back into space, mimicking the effect of huge volcanic eruptions.

The 1991 eruption of Mount Pinatubo in the Philippines, for example, ejected at least five cubic kilometres of ash and gas which rapidly spread around the globe, decreasing the average global temperature by 0.5C.

Climate engineering - or geoengineering, as it is often known - is a highly controversial subject.

As well as aerosol injection, ideas include devices to absorb carbon dioxide from the air, giant sunshields in space, and changing the reflectivity of land through planting different crop strains.

Proponents say research is needed into these technologies because humanity will probably need them one day, as society is unlikely to keep greenhouse gas emissions low enough to avoid dangerous impacts of climate change.

The Spice team - drawn from a number of universities as well as Marshall Aerospace - calculates that 10 or 20 giant balloons at a 20km altitude could release enough particles into the atmosphere to reduce the global temperature by around 2C.

But opponents argue that even testing could have harmful impacts, that there are questions of ethics and international law that remain unanswered, and that even raising the prospect of geoengineering distracts from initiatives to curb emissions.

Helena Paul, co-director of environment group EcoNexus, said she was "really pleased" at the latest news.

"We are certainly not ready to carry out experiments, and this project should not just be delayed, but should be cancelled immediately," she told BBC News.

"This is particularly important because while the scientists involved keep saying that reducing emissions is the primary necessity, they risk distracting attention from that necessity at a crucial moment."

At last year's UN Convention on Biological Diversity meeting, governments agreed that geoengineering projects should not have an adverse impact on biodiversity.

But that was one of very few attempts to regulate the issue internationally, which opponents argue is a big missing ingredient given that large-scale deployment of technologies in one country could have significant impacts in others.

Research shows that the UK public share some of these concerns; in surveys, very few people were unconditionally positive about the concept of geoengineering.

Over the next six months, the Spice team will engage with stakeholder groups, discussing the ethical, social and legal issues surrounding their project.

The details have yet to be worked out, but discussions are sure to involve opponents such as EcoNexus.

However, Dr Watson said there was a need to divorce the concept of researching these technologies from their actual deployment as a climate "fix".

"My personal framing of this is that there is a very big difference between being keen to research geoengineering and being an advocate for deployment," he said.

"I am not in any way an advocate for deployment."

BBC Source
 
It would use a balloon and a kilometre-long hose to spray water into the upper atmosphere - a prelude to spraying climate-cooling sulphate particles.
Is this a joke, wouldn't it be easier to use a plane or helicopter?
 
Ronson8 said:
It would use a balloon and a kilometre-long hose to spray water into the upper atmosphere - a prelude to spraying climate-cooling sulphate particles.
Is this a joke, wouldn't it be easier to use a plane or helicopter?
For two bathfuls of water, yes. But they're testing whether the hose/balloon method would work, because huge volumes of sulphite particles would be needed in a practical process.

Edit: I reckon the pump and hose will have to create/withstand over 100 times atmospheric pressure to get water that high.
 
The balloon is really just the tap end of a very long hose that you'd need in place in order to continually sprinkle the atmosphere with sulphites.
 
Cloud-seeding ships could combat climate change
It should be possible to counteract the global warming associated with a doubling of carbon dioxide levels by enhancing the reflectivity of low-lying clouds above the oceans, according to researchers in the US and UK. ...

Not so fast ... New research and analysis suggests cloud seeding to enhance reflection of solar radiation is not likely to have much if any beneficial effect.
Depressing Study Shows a Big Issue With Using Cloud Seeding to Solve Global Warming

The clouds that hang low and thick in our sky, reflecting sunlight back out into space, are melting into thin air as the world warms.

The loss will not only trigger greater climate changes than we expected, but new research suggests it could also undermine the potential of future geoengineering solutions.

The idea of seeding clouds with an injection of light-reflecting particles to reflect sunlight back into space – thereby 'cooling' the planet – is a controversial one, yet to be proven useful or even feasible in the real world.

Some scientists worry about the unforeseen dangers of meddling in our planet's climate any further, while others point out this climate-hacking solution does nothing to address ocean acidification or adverse ecosystem effects.

It's also only as good as the clouds in our sky, and in the coming century, there may be a lot less of those. Even in the most ideal scenario, where solar geoengineering works with no side effects, a new model suggests it may not be enough on its own.

If the world's carbon emissions continue to rise unfettered, we will trigger a much larger cascade of warming – cloud seeding or no.

"Hence, elevated greenhouse gas concentrations may trigger substantial global warming by reducing the cooling effect stratocumulus clouds provide," the authors of the new study write, "even when all or much of the effect of greenhouse gas at the top of the atmosphere is compensated by solar geoengineering." ...

FULL STORY: https://www.sciencealert.com/solar-...ld-off-global-warming-forever-scientists-warn.
 
Here are the bibliographic details and abstract for the newer study which disputes the effectiveness of cloud seeding to reduce atmospheric solar heating.

Solar geoengineering may not prevent strong warming from direct effects of CO2 on stratocumulus cloud cover
Tapio Schneider, Colleen M. Kaul, and Kyle G. Pressel
PNAS first published November 16, 2020
https://doi.org/10.1073/pnas.2003730117

Abstract

Discussions of countering global warming with solar geoengineering assume that warming owing to rising greenhouse-gas concentrations can be compensated by artificially reducing the amount of sunlight Earth absorbs. However, solar geoengineering may not be fail-safe to prevent global warming because CO2 can directly affect cloud cover: It reduces cloud cover by modulating the longwave radiative cooling within the atmosphere. This effect is not mitigated by solar geoengineering. Here, we use idealized high-resolution simulations of clouds to show that, even under a sustained solar geoengineering scenario with initially only modest warming, subtropical stratocumulus clouds gradually thin and may eventually break up into scattered cumulus clouds, at concentrations exceeding 1,700 parts per million (ppm). Because stratocumulus clouds cover large swaths of subtropical oceans and cool Earth by reflecting incident sunlight, their loss would trigger strong (about 5 K) global warming. Thus, the results highlight that, at least in this extreme and idealized scenario, solar geoengineering may not suffice to counter greenhouse-gas-driven global warming.

SOURCE: https://www.pnas.org/content/early/2020/11/10/2003730117
 
The Harvard-based SCoPEx effort has been proposing an experiment involving injecting aerosols into the stratosphere and gathering data on the aerosol cloud's behavior. This is proposed only as a test to gather data which may help inform ongoing debates on the practicality and effectiveness of manipulating the extent to which sunlight heats the earth.

SCoPEx: Stratospheric Controlled Perturbation Experiment

SCoPEx is a scientific experiment to advance understanding of stratospheric aerosols that could be relevant to solar geoengineering. It aims to improve the fidelity of simulations (computer models) of solar geoengineering by providing modelers with experimental results vital to addressing specific science questions. Such simulations are the primary tool for estimating the risks and benefits of solar geoengineering, but current limitations may make the simulations look too good. SCoPEx will make quantitative measurements of aspects of the aerosol microphysics and atmospheric chemistry that are currently highly uncertain in the simulations. It is not a test of solar geoengineering per se. Instead, it will observe how particles interact with one another, with the background stratospheric air, and with solar and infrared radiation. Improved understanding of these processes will help answer applied questions such as, is it possible to find aerosols that can reduce or eliminate ozone loss, without increasing other physical risks? ...

https://www.keutschgroup.com/scopex
 
The inaugural SCoPEx experiment, planned for launch from northern Sweden, has been canceled after resistance from various groups.
Test Flight for Sunlight-Blocking Research Is Canceled

A test flight for researching ways to cool Earth by blocking sunlight will not take place as planned in Sweden this June, following objections from environmentalists, scientists and Indigenous groups there.

The Swedish Space Corporation said this week it had canceled plans for the flight, in which it would have launched a high-altitude balloon, on behalf of researchers, from its facility in the Arctic. It would have been the first flight of a long-planned experiment called Scopex, a project led by scientists at Harvard University.

The corporation, which is government owned, said it had consulted “with both leading experts on geoengineering and with other stakeholders,” as well as with a Harvard committee that is advising the researchers. The decision not to conduct the test was made in agreement with the Harvard panel, it said.

The advisory committee issued its own statement saying it recommended that any test flights be suspended until it “can make a final recommendation about those flights based on a robust and inclusive public engagement in Sweden.”

Scopex is intended to better understand one form of solar geoengineering: injecting substances into the air to reflect some of the sun’s rays back to space and thus reduce global warming relatively quickly.

https://www.nytimes.com/2021/04/02/climate/solar-geoengineering-block-sunlight.html
 
For a year and a half now the international Climate Intervention Biology Working Group has been interacting monthly to discuss the pros and cons of mitigating global warming by solar radiation modification (SRM) - within which the approach of stratospheric aerosol intervention (SAI) discussed above is a subset.

This working group has now published a report expressing extreme caution about proceeding with such interventions without better understanding of the potential outcomes and ramifications.
A sun reflector for earth?

An international climate intervention workgroup publishes paper exploring the potential risks and benefits of a proposed high-tech climate intervention ...

Every month since September 2019 the Climate Intervention Biology Working Group, a team of internationally recognized experts in climate science and ecology, has gathered remotely to bring science to bear on that question and the consequences of geoengineering a cooler Earth by reflecting a portion of the sun's radiation away from the planet -- a climate intervention strategy known as solar radiation modification (SRM).

The group's seminal paper, "Potential ecological impacts of climate intervention by reflecting sunlight to cool Earth," was published in the most recent Proceedings of the National Academy of Sciences of the United States (PNAS).

"Participating in this working group has been quite eye-opening for me," said co-author Peter Groffman, an ecosystem ecologist ... "I was unaware that modeling climate intervention was so advanced, and I think that climate modelers were unaware of the complexities of the ecological systems being affected. It is a strong reminder of the importance of the need for multi-disciplinary analysis of complex problems in environmental science." ...

The costs and technology needed to reflect the Sun's heat back into space are currently more attainable than other climate intervention ideas like absorbing carbon dioxide (CO2) from the air. The working group anticipates their lively discussions and open access paper will encourage an explosion of scientific investigation into how a climate intervention strategy known as solar radiation modification (SRM), in tandem with greenhouse gas emissions reduction, would affect the natural world.

The feasibility of planetary-wide SRM efforts hinge on accurate predictions of its myriad outcomes provided by the well-established computer simulations of the Geoengineering Model Intercomparison Project (GeoMIP). The PNAS paper lays the foundation for expanding GeoMIP's scope to include the incredible range and diversity of Earth's ecosystems. ...

SAI would reduce some of the Sun's incoming radiation by reflecting sunlight back into space, similar to what happens after large volcanic eruptions. Theoretically, it would be possible to continuously replenish the cloud and control its thickness and location to achieve a desired target temperature.

But the paper reveals the under-researched complexity of cascading relationships between ecosystem function and climate under different SAI scenarios. ...

... SRM is not a magic bullet for solving climate change. Until the working group's efforts inspire new research into the effects of different climate intervention scenarios, SRM is more akin to a shot in the dark. ...

FULL STORY: https://www.eurekalert.org/pub_releases/2021-04/asrc-asr033021.php
 
Here are the bibliographic details and abstract for the published report. The full report (PDF format) is available at the link below.

Potential ecological impacts of climate intervention by reflecting sunlight to cool Earth
Phoebe L. Zarnetske, Jessica Gurevitchc, et al.
PNAS 2021 Vol. 118 No. 15 e1921854118
https://doi.org/10.1073/pnas.1921854118

As the effects of anthropogenic climate change become more severe, several approaches for deliberate climate intervention to reduce or stabilize Earth’s surface temperature have been proposed. Solar radia- tion modification (SRM) is one potential approach to partially counteract anthropogenic warming by reflecting a small proportion of the incoming solar radiation to increase Earth’s albedo. While climate science research has focused on the predicted climate effects of SRM, almost no studies have investigated the impacts that SRM would have on ecological systems. The impacts and risks posed by SRM would vary by implementation scenario, anthropogenic climate effects, geographic region, and by ecosystem, com- munity, population, and organism. Complex interactions among Earth’s climate system and living systems would further affect SRM impacts and risks. We focus here on stratospheric aerosol intervention (SAI), a well-studied and relatively feasible SRM scheme that is likely to have a large impact on Earth’s surface temperature. We outline current gaps in knowledge about both helpful and harmful predicted effects of SAI on ecological systems. Desired ecological outcomes might also inform development of future SAI implementation scenarios. In addition to filling these knowledge gaps, increased collaboration between ecologists and climate scientists would identify a common set of SAI research goals and improve the communication about potential SAI impacts and risks with the public. Without this collaboration, forecasts of SAI impacts will overlook potential effects on biodiversity and ecosystem services for humanity.

FULL REPORT: https://www.pnas.org/content/pnas/118/15/e1921854118.full.pdf
 
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https://www.msn.com/en-gb/news/worl...bon-than-thought/ar-AAMDeKi?ocid=winp1taskbar
 
More than 60 relevant experts have issued a joint open letter calling for solar geoengineering to be avoided as a strategy owing to dangers intrinsic to its implementation and ambiguities in evaluating its potential effects and effectiveness.
Dimming The Sun Is a Dangerous Gamble And Should Be Banned, Scientists Warn

Planetary-scale engineering schemes designed to cool Earth's surface and lessen the impact of global heating are potentially dangerous and should be blocked by governments, more than 60 policy experts and scientists said on Monday.

Even if injecting billions of sulphur particles into the middle atmosphere – the most hotly debated plan for so-called solar radiation modification (SRM) – turned back a critical fraction of the Sun's rays as intended, the consequences could outweigh any benefits, they argued in an open letter.

"Solar geoengineering deployment cannot be governed globally in a fair, inclusive and effective manner," said the letter, supported by a commentary in the journal WIREs Climate Change.

"We therefore call for immediate political action from governments, the United Nations and other actors to prevent the normalization of solar geoengineering as a climate policy option."
FULL STORY: https://www.sciencealert.com/dimming-the-sun-should-be-off-limits-scientists-warn
 
Here's the introduction to the Open Letter. The complete open letter text is accessible at the first link below. A supporting document with more detailed background information and rationale for non-use can be accessed at the second link below.
OPEN LETTER

We Call for an International Non-Use Agreement on Solar Geoengineering

We call for immediate political action from governments, the United Nations, and other actors to prevent the normalization of solar geoengineering as a climate policy option. Governments and the United Nations must assert effective political control and restrict the development of solar geoengineering technologies at planetary scale. Specifically, we call for an International Non-Use Agreement on Solar Geoengineering. ...

FULL TEXT (Open Letter):
https://www.solargeoeng.org/non-use-agreement/open-letter/

EXTENDED / SUPPORTING DOCUMENT:
https://wires.onlinelibrary.wiley.com/doi/10.1002/wcc.754
 
Lets try a space umbrella!

Mitigating climate change on Earth is such a dire challenge that scientists are seriously investigating every single option they can think of.

The latest idea is wild… but it's not outside the realm of possibility. Astronomer István Szapudi, of the University of Hawaiʻi Institute for Astronomy, reckons we could catch an asteroid, park it in front of Earth, and tether a parasol to it, to block some of the Sun's light.

The solar shield isn't a new idea. But Szapudi's alterations would greatly reduce the cost and difficulty of implementation, bringing it a step closer to achievable.

"In Hawaiʻi, many use an umbrella to block the sunlight as they walk about during the day," he explains. "I was thinking, could we do the same for Earth and thereby mitigate the impending catastrophe of climate change?"

sun-shield-concept-body.jpg


Artist's concept of the tethered solar shield. (Brooks Bays/UH Institute for Astronomy)

The idea of a solar shield isn't without merit. If it blocked just a small percentage of the sunlight constantly irradiating Earth, it could be sufficient to counteract rising temperatures; not, perhaps, an absolute solution, but a stop-gap that would give us a bit of time to work on things here on the surface.

The problem is that the sail would need a fair amount of mass as ballast to prevent it from being blown away by the solar wind and radiation pressure, and for gravitational stability – and getting that much mass into space would be difficult and expensive.

https://www.sciencealert.com/giant-...-can-help-fight-climate-change-scientist-says
 
Lets try a space umbrella!

Mitigating climate change on Earth is such a dire challenge that scientists are seriously investigating every single option they can think of.

The latest idea is wild… but it's not outside the realm of possibility. Astronomer István Szapudi, of the University of Hawaiʻi Institute for Astronomy, reckons we could catch an asteroid, park it in front of Earth, and tether a parasol to it, to block some of the Sun's light.

The solar shield isn't a new idea. But Szapudi's alterations would greatly reduce the cost and difficulty of implementation, bringing it a step closer to achievable.

"In Hawaiʻi, many use an umbrella to block the sunlight as they walk about during the day," he explains. "I was thinking, could we do the same for Earth and thereby mitigate the impending catastrophe of climate change?"

sun-shield-concept-body.jpg


Artist's concept of the tethered solar shield. (Brooks Bays/UH Institute for Astronomy)

The idea of a solar shield isn't without merit. If it blocked just a small percentage of the sunlight constantly irradiating Earth, it could be sufficient to counteract rising temperatures; not, perhaps, an absolute solution, but a stop-gap that would give us a bit of time to work on things here on the surface.

The problem is that the sail would need a fair amount of mass as ballast to prevent it from being blown away by the solar wind and radiation pressure, and for gravitational stability – and getting that much mass into space would be difficult and expensive.

https://www.sciencealert.com/giant-...-can-help-fight-climate-change-scientist-says
Asimov, IIRC in one of his essays made the somewhat facetious suggestion that if the Earth got too hot we could "paint Texas white." Coating a large area, preferably one where it would have minimal environmental impact with some highly reflective substance might be technically easier.
 
a reflective foil "sunshade' or parasol, in solar orbit a million miles sunward at the solar L1 point , would cast a much larger shadow on globally warmed earth. engineers calculate this can reverse the warming disaster. (see CBS news site, page for Jan. fifteen, 2001..COOLING THE PLANET).
we must talk this up- Kyoto is slow. Sunshade could be finished a year from now, and does not require compliance by thirty nations.
The sunshade is the only fast solution. it does not matter who wins the argument on the true cause. Sunshade cures ANY cause.
Incisive thinkers out there...it is up to you to drag the public away from the current solution discussion. Lives will be lost to heat stroke while the Kyoto debate drags on. (witness Bengal India)

John Newtol
More refs:
Journal of the British Interplanetary Society (JBIS), 44, 139-141 (1991).
H.S. Hudson, "A Space Parasol as a Countermeasure Against the Greenhouse Effect,"
Martyn Fogg's book 'Terraforming' discusses the concept in Chapter 4. Here's a 'Geoengineering' pdf
http://www.nap.edu/html/greenhouse/PostScript30.pdf
Thanks to Dr. Parkyn for these sources.
They need to leave the ideas to alleviate climate change to the geologists. They know more about the climate than astronomers.
 
Asimov, IIRC in one of his essays made the somewhat facetious suggestion that if the Earth got too hot we could "paint Texas white." Coating a large area, preferably one where it would have minimal environmental impact with some highly reflective substance might be technically easier.
There are places that are painting the black asphalt white and it seems to help. If all the streets of pheonix were painted white it might keep their summer highs down oto 110 F. Currently they are getting close to 120.
 
Asimov, IIRC in one of his essays made the somewhat facetious suggestion that if the Earth got too hot we could "paint Texas white." Coating a large area, preferably one where it would have minimal environmental impact with some highly reflective substance might be technically easier.
That would be a safer option than putting something up into space or spraying stuff around the upper atmosphere.
 
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