Solar radiation management (SRM or solar geoengineering) is a theoretical approach khổng lồ reducing some of the impacts of climate change by reflecting a small amount of inbound sunlight back out inkhổng lồ space. It is in the early stages of retìm kiếm, but it is already a controversial topic. It is clear that SRM has the potential lớn be very helpful or very damaging for those people and species most threatened by climate change, but it is very unclear what its full effects would be.

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SRM would not directly reduce concentrations greenhouse gases, và therefore numerous expert reports have sầu concluded that it could never be a complete solution khổng lồ global warming & does not represent a substitute for mitigation of greenhouse gas emissions. However, they have also concluded that it might be able to lớn reduce some climate risks lớn which Earth is already committed, though even for this more limited purpose whether it can be net positive khổng lồ humanity & the environment is unclear.


For instance, if it could be made khổng lồ work, SRM would be the only known method for quickly stopping the rise in global temperatures. It could even be used to lớn cool the planet, should that ever be deemed necessary. As such it might be able to reduce some damages while humanity decarbonizes the global economy, or it might offer a method for dealing with some of the climate risks associated with those greenhouse gases that have sầu already been emitted to lớn the atmosphere. The uncertainties around the effects of SRM are large though, and there is not nearly enough evidence yet available to lớn evaluate whether use of SRM would increase or decrease the impacts of climate change, & where.

What would SRM involve?

Different SRM techniques have been proposed, but the proposals receiving the most attention from researchers would involve sầu brightening marine clouds by spraying seawater into the lower atmosphere, or replicating the cooling effect of volcanoes by spraying reflective sulfate particles inlớn the upper atmosphere (the stratosphere).

Stratospheric aerosol injectionWhen very large volcanoes erupt they blast millions of tonnes of reflective sulphate particles inlớn the stratosphere. These particles circulate the planet on the powerful stratospheric winds, reflecting away a small amount of inbound sunlight và cooling the planet for a year or two. Stratospheric aerosol ejection would seek to lớn replicate this effect, with aeroplanes or balloons used lớn inject reflective sầu aerosol particles into lớn the upper atmosphere.

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Marine cloud brighteningLarge areas of ocean are covered in marine stratus clouds. Scientists have proposed that spraying tiny droplets of seawater into lớn these clouds could make them lighter và more reflective sầu. Whiter, brighter clouds reflect more sunlight bachồng out into lớn space, và would help cool the planet.

What about side effects?

It is not yet known what all the side effects of SRM could be, or whether they would be very damaging. Some possible side effects are known, however. For instance, stratospheric aerosols might delay the regeneration of the ozone layer. There might also be some health effects from the additional aerosols in the atmosphere, although these are not currently expected khổng lồ be large.


What about the societal và political dimensions?

The physical impacts of SRM are only one part of the story. Many people feel that the political dimensions could prove more difficult lớn manage than the physical dimensions. For instance, what would happen if a country used SRM unilaterally, & then other countries experienced extreme weather events that might have been caused by the geoengineering? How would the world achieve sầu widespread international agreement over how much SRM cooling khổng lồ do? Some countries might want the world a degree or two warmer, & some might want it a degree or two cooler. Also, there are concerns that the idea of SRM could distract politicians from the task of implementing deep cuts to lớn greenhouse gas emissions.

SRM retìm kiếm and governance questions

Many people và organizations have sầu called for more retìm kiếm. Basic calculations have indicated that SRM could be very cheap lớn deploy relative khổng lồ the costs of climate mitigation or adaptation, & so research and discussion usually focus on risks, benefits, uncertainties, and governance.

But research itself is controversial and it raises numerous questions:

Who decides if research proceeds, & what should be researched?Who pays for the research? Who benefits?What ensures that research is conducted in a transparent manner, and that all results are shared openly?How can the different research priorities of different groups be heard?What can be done to make sure that SRM retìm kiếm does not distract public & politicians from the task of cutting emissions of greenhouse gases?

These questions can shape the way that SRM develops, but there are no clear answers. A broad global conversation about SRM và the governance of related retìm kiếm is therefore required.

“I would lượt thích lớn have a reverse button for whatever is put in the stratosphere.“