Scientists Propose Safe and Experimental Way to Reduce Global Warming by Reflecting Sunlight Away from Earth.
As global temperatures continue to soar, the world's options for mitigating catastrophic warming are dwindling. Last year was the first full year over 1.5 degrees hotter than the 19th-century average, with fossil fuel emissions set to reach a new high in 2025. While permanent carbon removal technologies have made some progress, their annual removal of just tens of thousands of tonnes pales in comparison to the millions needed.
However, researchers are exploring an innovative idea - reflecting a small fraction of incoming sunlight away from Earth's surface. This concept has been on the table since 1965, when Lyndon B Johnson's science advisors proposed it as the only viable means of cooling the planet. The idea is not new, but the scientific understanding of how to make it work safely and effectively is still in its infancy.
In 1991, the massive eruption of Mount Pinatubo provided a natural experiment for stratospheric aerosol injection (SAI), which could potentially offset one degree of warming with just 12 million tonnes of sulfur dioxide per year. The benefits of SAI are undeniable - it has already proven to be an effective cooling agent in recent volcanic eruptions, with no measurable impact on global climate.
Yet, experts caution that this technology should not be employed without rigorous testing and governance. Careless or uncoordinated interventions could have catastrophic consequences, such as disrupting precipitation patterns. It is essential to clarify the risks of misuse and proceed with caution.
Researchers propose a phase-gated approach, inspired by the clinical trial model used in medicine, to develop safe and effective methods for studying SAI. The goal is to build confidence in predictions using laboratory work, computer models, and field experiments, while verifying key processes such as aerosol formation, dispersion, and interaction with the environment.
The proposed sequence of experimentation would start with a tiny amount of sulfur dioxide - approximately 10 tonnes - released at high altitudes to study its evolution without affecting the climate. This phase would be followed by larger-scale experiments to examine how aerosols mix and distribute in the stratosphere.
Only after researchers worldwide have scrutinized the data and drawn their own conclusions could governments make an informed decision about moving forward with SAI. If deemed viable, further research would involve deliberate and reversible deployment of small amounts of sulfur dioxide over a period of five years under strict observation.
The authors emphasize that generating evidence is crucial for making responsible decisions about any potentially transformative technology. They cite the UK's Advanced Research and Invention Agency (Aria) program as a significant step towards this goal, supporting research into the theoretical foundations required to determine the minimum scale for meaningful experiments.
By taking a cautious and transparent approach, researchers can address concerns about safety, efficacy, and governance, while providing policymakers with the evidence needed to make informed decisions. The only way forward is to proceed with careful planning, rigorous testing, and public accountability - anything less risks perpetuating climate denial or wishful thinking.
As global temperatures continue to soar, the world's options for mitigating catastrophic warming are dwindling. Last year was the first full year over 1.5 degrees hotter than the 19th-century average, with fossil fuel emissions set to reach a new high in 2025. While permanent carbon removal technologies have made some progress, their annual removal of just tens of thousands of tonnes pales in comparison to the millions needed.
However, researchers are exploring an innovative idea - reflecting a small fraction of incoming sunlight away from Earth's surface. This concept has been on the table since 1965, when Lyndon B Johnson's science advisors proposed it as the only viable means of cooling the planet. The idea is not new, but the scientific understanding of how to make it work safely and effectively is still in its infancy.
In 1991, the massive eruption of Mount Pinatubo provided a natural experiment for stratospheric aerosol injection (SAI), which could potentially offset one degree of warming with just 12 million tonnes of sulfur dioxide per year. The benefits of SAI are undeniable - it has already proven to be an effective cooling agent in recent volcanic eruptions, with no measurable impact on global climate.
Yet, experts caution that this technology should not be employed without rigorous testing and governance. Careless or uncoordinated interventions could have catastrophic consequences, such as disrupting precipitation patterns. It is essential to clarify the risks of misuse and proceed with caution.
Researchers propose a phase-gated approach, inspired by the clinical trial model used in medicine, to develop safe and effective methods for studying SAI. The goal is to build confidence in predictions using laboratory work, computer models, and field experiments, while verifying key processes such as aerosol formation, dispersion, and interaction with the environment.
The proposed sequence of experimentation would start with a tiny amount of sulfur dioxide - approximately 10 tonnes - released at high altitudes to study its evolution without affecting the climate. This phase would be followed by larger-scale experiments to examine how aerosols mix and distribute in the stratosphere.
Only after researchers worldwide have scrutinized the data and drawn their own conclusions could governments make an informed decision about moving forward with SAI. If deemed viable, further research would involve deliberate and reversible deployment of small amounts of sulfur dioxide over a period of five years under strict observation.
The authors emphasize that generating evidence is crucial for making responsible decisions about any potentially transformative technology. They cite the UK's Advanced Research and Invention Agency (Aria) program as a significant step towards this goal, supporting research into the theoretical foundations required to determine the minimum scale for meaningful experiments.
By taking a cautious and transparent approach, researchers can address concerns about safety, efficacy, and governance, while providing policymakers with the evidence needed to make informed decisions. The only way forward is to proceed with careful planning, rigorous testing, and public accountability - anything less risks perpetuating climate denial or wishful thinking.
. I mean, we're already at a critical point where we need to take drastic measures to reduce emissions and limit the damage. And while carbon removal technologies are being explored, they're not quite scalable enough just yet.
. It's been around since the 60s, but only now that we have better understanding of how it works can we seriously consider implementing it on a large scale. The idea of starting small with tiny amounts and gradually increasing the scale is really smart too 
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. It's so easy to get caught up in the excitement of exploring new ideas without thinking about the potential risks and consequences. But if we take a cautious approach and prioritize transparency, safety, and efficacy, then this technology could be a real lifesaver 
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. Using a phase-gated approach to study SAI can help us build confidence in our predictions and make more informed decisions. And by involving researchers worldwide and policymakers, we're creating a more collaborative and accountable process that benefits everyone 
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... like, we need a solution NOW but at the same time I get it that we can't just rush into something without being super careful 
... this idea of reflecting sunlight away from Earth sounds kinda scary but also kinda hopeful 
... if only we could find a way to do it safely and effectively without messing up the whole planet 
! 12 million tonnes of sulfur dioxide per year is actually kinda tiny compared to the millions needed to offset warming 
. I mean, who wouldn't want a slightly cooler planet? 
Just gotta make sure it's safe and not gonna mess with the weather patterns 
. Maybe they should start small and work their way up to avoid any catastrophic consequences 
. Can you imagine the lab work and testing that'd go into this? 
It seems like a solid plan to test and verify before making any big decisions 
. Fingers crossed it works out! 
. It's crazy to think that scientists have been proposing this since 1965, and now we're finally getting closer to making it work 
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. It's all about building confidence in our predictions and ensuring that we're not playing with fire 
. If done right, this could be a game-changer in our fight against global warming 
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. Anyway, back to climate stuff... sulfur dioxide sounds kinda like a fancy name for stinky gas 
, don't you think?
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. I love how scientists are taking a cautious approach, like they're playing with fire 
. Let's just hope that governments and policymakers are paying attention and don't get caught up in climate denial or wishful thinking 
. And if we can learn from nature, then why not try it? 
it sounds like we're still playing around with science here... 
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. So, yeah, I'm all for this SAI research program, but we need to keep it on track and not get ahead of ourselves 
I mean, scientists are basically trying to reflect sunlight away from Earth like it's a giant solar panel... not gonna lie, that sounds kinda like my aunt's backyard gazebo project 
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. But we gotta be careful not to mess up the whole precipitation pattern thing... that's like trying to predict the weather on the beach without an umbrella 
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. With their phase-gated approach, they're taking a cautious and transparent route, which is more like my mom's cooking – you know, "too much salt" 
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. It's that old saying about how we're all just winging it until someone else shows up to tell us what to do. This whole thing feels like a huge game of cosmic chess, where the pieces are our very planet and its inhabitants. Can we really afford to be careless with this?
. We need to make sure that this tech is tested and regulated properly before we start deploying large amounts of sulfur dioxide into the stratosphere. I'm not saying it can't be done, but we need to approach this with caution and careful planning 
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. That makes sense - if it's safe for human trials, why shouldn't we apply those same principles to large-scale experimentation? 
. Now, here's this crazy idea of reflecting sunlight away from Earth - it sounds like something straight outta a sci-fi movie 
! I mean, the concept has been around since '65, but it's only now that they're trying to make it work safely and effectively.
. We can't just start spraying sulfur dioxide around without knowing what we're doing. I remember when Mount Pinatubo erupted in '91 - that was like a natural experiment right there! 
But now they want to do it on a much bigger scale, and that's where things get really interesting.
. We need to make sure that we're not rushing into something without thoroughly understanding the consequences. The proposed sequence of experimentation, starting with tiny amounts of sulfur dioxide and working our way up, makes total sense to me. And I'm all for governments making informed decisions based on evidence, rather than relying on unproven technologies or wishful thinking 
. If we continue to prioritize careful planning, rigorous testing, and public accountability, I think we might just find ourselves on the path to solving this global challenge 
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. We need to make sure scientists and governments are on the same page before we consider deploying this technology on a larger scale