What scientists are learning about geoengineering from satellite pollution : NPR

EMILY FENG, HOST:

Earth has a new set of constellations…

(SOUNDBITE OF ARCHIVED RECORDING)

UNIDENTIFIED PERSON #1: Three, two, one, (inaudible).

FENG: …Satellite constellations. Billionaire space entrepreneurs are launching tens of thousands of satellites into orbit.

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UNIDENTIFIED PERSON #1: Go SpaceX. Go Starlink.

UNIDENTIFIED PERSON #2: And lift off of Falcon 9.

UNIDENTIFIED PERSON #3: And lift off of Falcon 9. Go SpaceX. Go Starlink.

FENG: These networks run major internet services like Starlink or Global Positioning data, or GPS. And all these rockets are having an impact on the Earth’s atmosphere. Eloise Marais is a professor at University College London and author of a new study all about those satellite mega constellations. Welcome.

ELOISE MARAIS: Hi.

FENG: Professor, tell me about these launches. What is the impact of all these satellite launches?

MARAIS: Yeah, there’s two sources of air pollution that come from these satellite launches. The rockets that are launching satellites into space are producing pollutants that are being released into all layers of the atmosphere as the rocket ascends. But then also when these satellites reach end of life, they need to be discarded. And the only viable way we have to discard these satellites is to burn them through the higher layers of the atmosphere and hope that entirely disintegrate.

FENG: What impacts on the climate do they have?

MARAIS: This is a little bit unusual. We have particles that are sort of small, suspended pieces of material in the atmosphere that come from these rocket launches called black carbon or soot particles. These are being put higher up in the atmosphere, and they’re actually blocking some of the sun’s incoming rays and cooling the atmosphere down. So in that way, they’re a little bit like a geo engineering experiment, some of these proposed ideas to try and cool the lower layers of the atmosphere.

FENG: Wow. So there’s so many soot particles high up in the atmosphere that they’re able to cool Earth down.

MARAIS: Yeah.

FENG: How much are they cooling Earth down by?

MARAIS: Currently, not a lot. The amount of black carbon that’s produced by these rockets – mostly Falcon 9 rockets that SpaceX launches – is very, very small in comparison to pollution sources closer to the surface of the Earth, like ships and cars and other sources that produce black carbon. But because they stay there for so long, 2 1/2 to three years, the impact is actually greater. So the longer a pollutant stays in the atmosphere, the bigger the effect they have. So even though it’s a small effect now, if the space industry grows, it will very quickly become a bigger impact.

FENG: There’ve been a couple of ideas floated around where people intentionally want to put particles high up in the atmosphere to cool Earth down. So I have to ask, if this is being done accidentally because of satellite launches, is that cooling down a good thing?

MARAIS: It sounds like a good thing. That’s why we’re debating the idea of geo engineering as a way to very quickly cool the planet to try and reverse some of the warming that’s happening as a result of greenhouse gases, but we haven’t done this yet. We haven’t done it to scale because there are so many unintended consequences of geo engineering the planet. We could start to deplete ozone in the higher layers of the atmosphere. We could change circulation patterns of the atmosphere, these sort of processes that move air hundreds of kilometers in the higher layers of the atmosphere. So it is an accidental geo engineering experiment without the careful ethical forethought that’s needed before we adopt geo engineering.

FENG: OK, back here on Earth, is there anything governments should be doing to regulate in the short term things like satellite launches?

MARAIS: I think the issue is that we don’t really have a solid regulatory framework to try and govern how we use space responsibly and sustainably and ethically. And unfortunately, is – it is a shared space, so it does require governments to work together, which at this stage does seem to be a big challenge.

FENG: That is Eloise Marais, professor at University College London. Thank you.

MARAIS: Thank you very much.

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