GEOENGINEERING LÀ GÌ

Solar radiation management (SRM or solar geoengineering) is a theoretical approach to lớn reducing some of the impacts of climate change by reflecting a small amount of inbound sunlight bachồng out inlớn 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 to 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, and therefore numerous expert reports have sầu concluded that it could never be a complete solution lớn global warming and does not represent a substitute for mitigation of greenhouse gas emissions. However, they have also concluded that it might be able to reduce some climate risks to which Earth is already committed, though even for this more limited purpose whether it can be net positive sầu to lớn humanity and the environment is unclear.

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For instance, if it could be made to work, SRM would be the only known method for quickly stopping the rise in global temperatures. It could even be used khổng lồ 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 lớn the atmosphere. The uncertainties around the effects of SRM are large though, & there is not nearly enough evidence yet available khổng lồ evaluate whether use of SRM would increase or decrease the impacts of climate change, & where.

What would SRM involve?

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

Stratospheric aerosol injectionWhen very large volcanoes erupt they blast millions of tonnes of reflective sulphate particles inkhổng lồ 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 lớn replicate this effect, with aeroplanes or balloons used lớn inject reflective sầu aerosol particles into 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 these clouds could make them lighter and more reflective sầu. Whiter, brighter clouds reflect more sunlight baông chồng out inkhổng lồ 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 to be large.

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What about the societal & political dimensions?

The physical impacts of SRM are only one part of the story. Many people feel that the political dimensions could prove sầu more difficult to 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 widespread international agreement over how much SRM cooling khổng lồ do? Some countries might want the world a degree or two warmer, and 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 greenhouse gas emissions.

SRM retìm kiếm and governance questions

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

But retìm kiếm itself is controversial and it raises numerous questions:

Who decides if research proceeds, and what should be researched?Who pays for the research? Who benefits?What ensures that retìm kiếm is conducted in a transparent manner, và that all results are shared openly?How can the different retìm kiếm priorities of different groups be heard?What can be done to lớn make sure that SRM research does not distract public and 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 and the governance of related retìm kiếm is therefore required.


“I would like to have sầu a reverse button for whatever is put in the stratosphere.“