About Us
SRM360 is a non-profit knowledge broker informing people about solar geoengineering, so they can contribute to critical decisions.
Solar geoengineering is not a solution to climate change, but it might help to reduce some of its impacts
SRM Guide
Why Are People Considering SRM?
As climate extremes affect people and ecosystems with increasing frequency and severity, there is growing discussion about whether a new set of technologies could help. Sunlight reflection methods (SRM) – also known as solar geoengineering or solar radiation modification – describe a set of ideas to reflect a small fraction of incoming sunlight to cool the planet.
Sunlight reflection methods
Sunlight reflection methods (SRM) are hypothetical approaches to lower global temperatures by increasing the amount of sunlight reflected to space.
Stratospheric aerosol injection (SAI)
WHAT'S THE IDEA?
Tiny particles released in the stratosphere would directly reflect a small fraction of sunlight.
Sunlight
COULD IT WORK?
There is no doubt that SAI could produce a large cooling effect, and it appears feasible to do with new, specially designed, high-altitude jets.
HOW WOULD WE KNOW?
Detailed modeling studies will be essential for evaluating SAI’s climate consequences and potential side effects, and field experiments could help address some uncertainties.
CLIMATE RESPONSE
SAI could produce an even, global cooling effect, reducing many climate change impacts. However it could also produce greater reductions in rainfall in some regions.
SIDE EFFECTS
SAI would delay the recovery of the ozone hole, add somewhat to acid rain, and make the sky a little whiter.
Marine cloud brightening (MCB)
WHAT'S THE IDEA?
Sea salt particles would be sprayed from ships to enhance the reflectivity of low-lying clouds.
COULD IT WORK?
It is possible MCB could be scaled to produce a regional to global cooling effect, but developing effective sprayers is technically challenging and the cloud response is uncertain.
HOW WOULD WE KNOW?
Small-scale field experiments will be essential for evaluating MCB’s feasibility, and climate modeling will be needed to evaluate its potential consequences.
CLIMATE RESPONSE
Models suggest large-scale MCB deployment could decrease temperatures on regional to global scales, while smaller scale efforts might provide local benefits such as short-term relief for heat-stressed ecosystems like the Great Barrier Reef.
SIDE EFFECTS
Uneven cooling of the sea surface could change atmospheric circulation and precipitation patterns.
SRM360; United Nations Environment Programme
Stratospheric aerosol injection (SAI)
Marine cloud brightening (MCB)
Sunlight
Sea salt particles would be sprayed from ships to enhance the reflectivity of low-lying clouds
Tiny particles released in the stratosphere would directly reflect a small fraction of sunlight.
WHAT'S THE IDEA?
There is no doubt that SAI could produce a large cooling effect, and it appears feasible to do with new, specially designed, high-altitude jets.
It is possible MCB could be scaled to produce a regional to global cooling effect, but developing effective sprayers is technically challenging and the cloud response is uncertain.
COULD IT WORK?
Detailed modeling studies will be essential for evaluating SAI’s climate consequences and potential side effects, and field experiments could help address some uncertainties.
Small-scale field experiments will be essential for evaluating MCB’s feasibility, and climate modeling will be needed to evaluate its potential consequences.
HOW WOULD WE KNOW?
SAI could produce an even, global cooling effect, reducing many climate change impacts. However it could also produce greater reductions in rainfall in some regions.
Models suggest large-scale MCB deployment could decrease temperatures on regional to global scales, while smaller scale efforts might provide local benefits such as short-term relief for heat-stressed ecosystems like the Great Barrier Reef.
CLIMATE RESPONSE
SAI would delay the recovery of the ozone hole, add somewhat to acid rain, and make the sky a little whiter.
Uneven cooling of the sea surface could change atmospheric circulation and precipitation patterns.
SIDE EFFECTS
SRM360; United Nations Environment Programme
Stratospheric aerosol injection (SAI)
Marine cloud brightening (MCB)
WHAT'S THE IDEA?
Tiny particles released in the stratosphere would directly reflect a small fraction of sunlight.
Sunlight
Sea salt particles would be sprayed from ships to enhance the reflectivity of low-lying clouds.
There is no doubt that SAI could produce a large cooling effect, and it appears feasible to do with new, specially designed, high-altitude jets.
It is possible MCB could be scaled to produce a regional to global cooling effect, but developing effective sprayers is technically challenging and the cloud response is uncertain.
COULD IT WORK?
Detailed modeling studies will be essential for evaluating SAI’s climate consequences and potential side effects, and field experiments could help address some uncertainties.
Small-scale field experiments will be essential for evaluating MCB’s feasibility, and climate modeling will be needed to evaluate its potential consequences.
HOW WOULD WE KNOW?
SAI could produce an even, global cooling effect, reducing many climate change impacts. However it could also produce greater reductions in rainfall in some regions.
Models suggest large-scale MCB deployment could decrease temperatures on regional to global scales, while smaller scale efforts might provide local benefits such as short-term relief for heat-stressed ecosystems like the Great Barrier Reef.
CLIMATE RESPONSE
SAI would delay the recovery of the ozone hole, add somewhat to acid rain, and make the sky a little whiter.
Uneven cooling of the sea surface could change atmospheric circulation and precipitation patterns.
SIDE EFFECTS
SRM360; United Nations Environment Programme
The world must focus on emissions cuts, but critical decisions are needed on solar geoengineering
None of these methods could replace essential emissions cuts – they are not a “solution” to climate change. At best, they could help limit some climate impacts while the essential work of decarbonisation accelerates. However, these approaches would also introduce new risks and much is still uncertain.
Emissions cuts, carbon removal, and SRM
Emissions cuts and carbon dioxide removal (CDR) tackle the root cause of climate change, and sunlight reflection methods (SRM) could limit warming while they work.
GLOBAL TEMPERATURE INCREASE
No emissions cuts
Temperatures would continue to rise.
Cut emissions
Eliminating CO2 emissions would stop global warming, but not reverse it.
4.0°C
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
2000
2100
2200
2300
2400
Reflect sunlight
SRM could offset global warming while emissions cuts and CDR work.
Remove carbon
CDR could then slowly lower temperatures.
Source: Based on Boselius et al. (2025), Oxford Open Climate Change
GLOBAL TEMPERATURE INCREASE
4.0°C
No emissions cuts
Temperatures would continue to rise.
CUT EMISSIONS
Eliminating CO2 emissions would stop global warming, but not reverse it.
3.5
3.0
2.5
2.0
REMOVE CARBON
CDR could then slowly lower temperatures.
1.5
REFLECT SUNLIGHT
SRM could offset global warming while emissions cuts and CDR work.
1.0
0.5
2000
2050
2100
2150
2200
2250
2300
2350
2400
Source: Based on Boselius et al. (2025), Oxford Open Climate Change
SRM Guide
Why Are People Considering SRM?
Decisions about whether or how to develop these technologies could have consequences for generations to come – for better or for worse.
The world faces critical decisions about SRM technologies today. These include decisions around research, development, policy, and governance. Making these decisions wisely will require weighing up the risks of developing these technologies against the risks of a dangerously warming world without them.
The pathway to poor decisions on SRM is short, but wise decisions that benefit people and ecosystems as a whole will take a lot of work.
We inform people about solar geoengineering so they can contribute to these critical decisions
Many groups need to be involved, in many places. This includes civil society, policymakers, media, think tanks, entrepreneurs, and funders. Without broad participation, a small group of actors could drive decisions with world-changing consequences.
But many groups do not have the knowledge or tools they need to engage. SRM360 works with experts around the world to create content that people need to get informed and take part in decisions – in time to make a difference.
Our vision
SRM360 works for a world where people have the best information available to engage with and take part in wise decisions about sunlight reflection methods, as part of urgent efforts to reduce the harms of climate change.
- Where researchers inform the world about how the risks of SRM compare to the risks of a warming world;
- Where groups across society come together to develop effective governance and cooperate to guide research and manage risks;
- Where, one day, the world can either responsibly reject SRM or develop and deploy it wisely alongside other climate policies.
Our mission
SRM360 aims to provide people around the world with the information they need to engage in decisions about sunlight reflection methods.
- SRM360 bridges the gap between experts and wider society, making sense of what is known and unknown about SRM;
- SRM360 produces accessible content and original analyses that can be shared and reused widely;
- SRM360 reaches out to people around the world, to ensure the broadest possible understanding of this rapidly developing field.
Our position
SRM360 takes no position on whether SRM should be used. But we believe that this idea cannot be ignored and that the world should be moving towards making informed decisions about it. That means we advocate for further research and assessment so that the risks of SRM can be weighed against the risks of climate change.
Our goal is to provide audiences across society with the information they need to contribute to an informed discussion on SRM and to reach their own conclusions about it.
Learn more about how we achieve this mission on our How We Work page.