WIRED: Would you notice this? WIRED: Would we be able to see this?
KR: Yes, it is on an absolute scale. It alters the ratio between direct and diffuse radiation. It would make the sky a little brighter and the sky a little less whiter. It’s certainly less than the difference in temperature between the desert and the city. My opinion is that the problem with the white skies is not the most important.
WIRED: What about concerns about toxicology and other issues? Is this stuff safe to all living things on Earth?
KR: It’s not benign—it’s the same stuff that comes out of power plants. It can cause serious illness to crops and people when it is present in large amounts. The amount of it you need in the stratosphere, on a scale smaller than the emissions from power plants, is still very important. It’s spread across the globe.
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. This is due to the fact that the particles move towards poles, mainly before they precipitate out from the stratosphere.
WIRED: 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.
KR: It’s complicated legally 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]The atmosphere stays for an average of one year and a quarter. They spread and radiative effects immediately take effect. 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 you stopped spraying for two years.
The WIRED Guide to Climate Change
The world is becoming warmer, but the weather is getting worse. Here’s everything you need about what humans can do stop destroying the planet.
I have difficulty understanding how we get here. NotIt’s so affordable that I will do it. 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 were to decarbonize quickly taking CO2 out of the atmosphereIt will still take a decade for the consequences to be felt. The climate response begins immediately, unlike blocking sunlight.
WIRED: I have seen modeling that shows that if you suddenly stopped solar geoengineering you would have a problem with temperature dramatically climbing and imperiling species.
KR: 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 catastrophic if our drinking water was not treated. It’s important that humans continue doing the things they love or it will be catastrophic.