Do you think climate change is confused? Wait until geoengineering

WIRED: Will we notice that? Will we see anything visually?

KR: Yes, on an absolute scale. Changes the ratio of direct and diffuse radiation. The idea is that on average the sky will become a little whiter and, for example, the sunsets will become a little brighter. It is definitely much less than the difference between moving from the California desert to the city. The white sky thing is also not the biggest problem, in my opinion.

WIRED: How about worries about toxicology? Is this a benign thing for living beings on Earth?

KR: It’s not benign – it’s the same thing that comes from power plants. High concentrations of it in one area make people and cultures ill. But in terms of scale, the amount you need in the stratosphere is much less than what we emit from power plants, and it’s spread all over the planet.

Humans have also done some research on this, and it seems that probably the greatest risk of particles would be for something like sensitive ecosystems at high latitudes – so polar ecosystems that are not very exposed to urban pollution at the moment, but will get more than that. Especially because the particles move to the poles, in general, before settling out of the stratosphere.

WIRED: Let’s say a country unilaterally says, “We’re going to do this.” They want to cool their own country by spraying the stratosphere, and it doesn’t matter if it covers the planet.

CoR: From a legal point of view, this is complicated because countries have their own airspace to space, in principle. It’s a bit ambiguous. So people can spray something over their country and it will go anywhere. And then [the particles] remain in the atmosphere for an average of about a year and a half. They spread and the radiation effects take effect immediately. That is why after a large volcanic eruption you immediately see a drop in global temperature, which lasts about a year to two years and then falls again. So you don’t have to spray anything every day, not necessarily. If you stop doing it for two years, the effect will disappear.

It’s hard for me to see how we are no I will actually do it at this point because it is so cheap. The effects of climate change already seem so devastating that I do not see in this world how such a low-cost solution cannot be implemented by anyone. There is simply nothing else in the world that can cool the planet so quickly. Even if we start decarbonizing quickly and removing CO2 from the atmosphere, it is still a decade of consequences. As long as it blocks sunlight, the climatic reaction begins immediately.

WIRED: I’ve seen some models that if you suddenly stop solar geoengineering, you’ll have a temperature problem dramatically climbing and endangered species.

CoR: If the program was disrupted and we blocked a lot of warming with stratospheric geoengineering, you would get that really fast warming if someone stopped doing it. I mean, it would be catastrophic if we stopped treating our drinking water, right? There are things that people do that we need to keep doing, or it’s catastrophic.