This story was first published by Wiredand appears here as part Climate Desk collaboration.
Here’s the thing about the stratosphere, the region between six and 31 miles up in the sky: If you really wanted to, you could turn it pink. Or green. Or whatever else you like. You could spray some colourant up there and the stratospheric winds will blow the material around the globe. It would eventually fade and the sky would return to its original color after a year or so. It was a clever little prank.
This is the concept behind a Solar geoengineering technique known as stratospheric aerosol injection, only instead of a pigment, engineers would spray a sulfate that bounces some of the sun’s radiation back into space, an attempt at cooling the planet. It’s the same principle behind a supervolcano loading the stratosphere with aerosols and blocking out the sun. It would also rely on the winds spreading the material evenly.
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“If you do it in one place, it’s going to affect the whole planet,” says climate scientist Kate Ricke, who studies the intersection of geoengineering, human behaviour, and economics at Scripps Institution of Oceanography. “Not just because you’ve cooled down and changed the global energy balance, but because the particles spread out.”
While it’s not likely that someone will colourize the atmosphere any time soon, it’s getting increasingly likely that someone will decide it’s time for stratospheric aerosol injection. Global temperatures are not rising at the same rate as pre-industrial levels. Emissions aren’t declining at all. The climate crisis is worsening.
Science is the key isn’t ready. This is an anthropogenic geoengineeringUnintended consequences could occur, such as droughts in some regions and severe storms elsewhere. Additionally, if engineers stopped spraying aerosols into the atmosphere abruptly, temperatures could swing back to where it started. Defending species and crops.
However, stratospheric aerosol spray would be very affordable. And there’s nothing stopping countries from unilaterally deciding to spray their airspace, even though those materials would ultimately spread around the globe. “I just have a hard time seeing with the economics of it how it doesn’t happen,” says Ricke. “To me, that means that it’s really urgent to do more research.”
What are people reading?
WIREDRicke and I sat down to discuss the allure of the allure. Geoengineering can lead to potential pitfalls, what makes it so politically perilous, and how scientists can make sense of it — for the good of humanity and the planet. This conversation has been condensed for clarity and edited.
Can you give me an idea of the scale that we’d be talking about with solar geoengineering — both spatial scales and timescales?
Let’s suppose you want to geoengineer today to stabilize the global temperature or bring it down a bit. A fleet of planes capable of reaching the stratosphere is what you need. We are talking about a fleet of aircraft capable of reaching the stratosphere.
Someone will hack the atmosphere to cool down the planet. Climate scientist @katericke says that we need to do more research about the consequences. #ClimateChange #SolarGeoengineering
The way the stratosphere works, is that once you are up there, the stratospheric wind takes things around the planet in bands of latitude. Things then migrate slowly over time, in bands of latitude, from the equatorial regions to the Poles. Finally, particles fall near the Poles. You don’t have to fly through the entire stratosphere spraying stuff. It takes a lot to spread it out. That’s why you can’t do geoengineering in the stratosphere over one area.
What would we see? Visually, could we see this?
Yes, it does on an absolute scale. It alters the ratio between direct and diffuse radiation. The idea is that the sky would be a little whiter and sunsets would be a little more vivid. It is certainly less than the difference in temperature between the desert and the city. I don’t think the white skies issue is the greatest problem.
Are there any concerns about toxicology? Is this stuff safe for living creatures?
It’s not benign — it’s the same stuff that comes out of power plants. It can make crops and people sick if there are large amounts of it. However, it is much smaller in terms of scale than what we produce from power plants. It’s spread all over the planet.
People have done some studies on this, too, and it seems like probably the biggest risk from the particles would be to sort of sensitive high-latitude ecosystems — so polar ecosystems that don’t get very much exposure to urban pollution right now but would get more from this. Because the particles are moving towards the Poles before they precipitate from the stratosphere, this is especially true.
Say a country unilaterally says, ‘We’re going to do this.’ They want to cool down their own country by spraying the stratosphere, and it doesn’t matter if it’s going to wrap around the planet.
Legally, it’s complicated because each country owns their airspace up until space. It’s a little unclear. It could be sprayed all over the country, and it would travel everywhere. And then [the particles]They stay in the atmosphere on average for about a year and half. They spread out and radiative effects take place immediately. After a large volcanic eruption, the global temperature drops immediately. This lasts for approximately one to two years before it returns to normal. You wouldn’t have to spray stuff every day. The effect would disappear if it was stopped for two years.
It’s hard to see how we are getting there. NotBecause it’s so cheap, I’m going to do it now. Already, the effects of climate change look so disruptive that I don’t see how anyone can implement such a low-cost solution. There is nothing else that can cool the planet as fast as climate change. Even if we decarbonized rapidly, Remove CO2 from the atmosphereIt will still take a decade for the consequences to be felt. While blocking sunlight is one thing, the climate response to it starts immediately.
I have seen some modeling that shows that if you suddenly stopped solar geoengineering you would have a problem with temperature The species are imperiling and rapidly climbing in numbers.
If the program was disrupted and we were blocking a lot warming with stratospheric Geoengineering, then you would see this really rapid warming if somebody stopped doing it. It would be a catastrophe if we stopped treating our drinking waters. We must continue doing certain things as humans, or it will be catastrophic.
The technology isn’t so complicated that we would only need to keep the one who developed it. So I’m not so sure that the argument about technology being the biggest problem is true. We already know how to do it. It’s possible for a small country to do it. The resources are so large that it would be difficult for one individual or a very small nation to do it. It’s not as difficult as nuclear weapons, or something similar.
Is science sound enough to allow us to make these decisions? Given the lack of international co-operation, is this even possible?
There might be some technical experts, like me or other people who have worked on this, who would say: ‘Yes, I’ve seen enough to believe it.’ But in order to have collective decision-making at the global scale, you need science that’s viewed as legitimate by everyone. Not EveryoneBut it is a lot of people. We’re not there yet, by a long shot, with geoengineering.
This is why we need to do more research. We need more diversity in who is doing the research and where. Because the results need to be seen as legitimate by a larger number of people. They aren’t right now. This is absolutely false.
Because there are a few elite white university students in North America and Europe that have done all the research. People don’t trust elites like this. It is crucial that the ministry of environment in Bangladesh has someone who is Bangladeshi speaking to them about geoengineering science. This is my biggest concern with current science. If you look at certain areas in climate science, you’ll see that we repeat the same thing over-and-over. But there has been some value to that, too — replication and repetition. It builds consensus and builds trust in science.
Country-scale commitments to reduce emissions One thing is one.This applies to everyone simultaneously, as we share the same atmosphere. Is there going be agreement?
We are not at the point where we can reach a global consensus on geoengineering. Not even close. But it seems more likely that this will occur. NotWith a worldwide consensus. There are certain actors who, if they did it would be constrained and constrained by larger actors. But geoengineering is not something that can be done by only a few actors. Because the alternative is: Are you willing to go into war because it’s too bad?
What about moral hazard? Is it not possible to reduce emissions by geoengineering?
Moral hazard is a legitimate concern and it’s a major one. The results of empirical research are mixed. It doesn’t seem like it. [for]Individual humans can be put in behavioural experiments to see if there is a moral hazard to geoengineering. Geoengineering is scary and crazy, so it is better to tell people about it in controlled situations. They see it a sign of climate change.
This is me editing about my fellow climate scientists. But I think most climate researchers don’t like geoengineering. The moral hazard is the main reason why they don’t like it. They think we’ve got to tell people ‘This is a bad idea’ as long as possible because of that. They’re probably right. But there is a risk that if the climate gets worse, people will do geoengineering anyway. We’re not ready for it.