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On our current carbon trajectory, we're committing future generations to interventions on this scale, or to catastrophe. A better, but more expensive idea is t
by unchocked 6y ago
On our current carbon trajectory, we're committing future generations to interventions on this scale, or to catastrophe.
A better, but more expensive idea is to build a giant sunshade at Earth-Sun Lagrange 1, a gravitationally stable point well beyond the Moon's orbit. It could be constructed with raw materials from the Moon and near-Earth asteroids, and the logistical capacity is within the design goals of SpaceX's Starship fleet.
It's expensive, and it's a giant band-aid until planetary CO2 removal is feasible. But building it would make humanity a truly interplanetary species, and benefit all of humanity for about the same cost as a city on Mars.
- mchusma 6y agoCame here to say something similar. A giant sun shade is vastly preferable to this article's approach. Issac Arthur's podcasts are great to listen to for this sort of thing. One reddit discussion on the concept: https://www.reddit.com/r/IsaacArthur/comments/9q6ngk/math_on_space_sunshade/ https://www.reddit.com/r/IsaacArthur/comments/9q6ngk/math_on...
- shoo 6y agoThe giant sunshade idea is much more expensive and fragile than relatively dumb alternatives such as spraying SO2 or water into the atmosphere to deflect sunlight, I don't really understand how sunshade could be argued as a "better" solution. Re "band-aid" -- I agree -- all solutions of this form that aim to partially mitigate one unwanted consequences of rising CO2 without addressing other consequences or halting the rise of CO2 are unlikely to result in a stable solution & instead just buy time.
- NateEag 6y agoIf the sunshade has undesirable consequences, you can just move it. It's much harder to undo terraforming attempts.
- unchocked 6y agoA sunshade doesn't involve chemical modification of our atmosphere, and its effects are reversible (it's a solar sail and can change its orbit when required). As to expense, it's an opportunity for the space industry to contribute to solving the #1 problem on Earth. The Starship fleet is being built anyway. As a fringe benefit, if made of thin-film photovoltaics a sunshade could generate ~300TW of electricity. Compare that to current terrestrial consumption of 17TW. It creates enough energy and in-space manufacturing capacity to unlock the solar system.
- dr_dshiv 6y agoBuying time seems like a good idea
- Analemma_ 6y agoI don't think this is actually feasible. [0] suggests you would need a mirror of 600,000 square miles (~700 miles to a side) at the L1 point to block 1% of solar radiation. And Lagrange points aren't actually gravitationally stable, you need station-keeping thrusters. Not sure how we'd go about pushing a wall of mirrors the size of France. [0]: https://www.livescience.com/22202-space-mirrors-global-warming.html https://www.livescience.com/22202-space-mirrors-global-warmi...
- unchocked 6y agoIt's a solar sail, so you can control it by differential albedo change. Here's a paper on the theory: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0136648 https://journals.plos.org/plosone/article?id=10.1371/journal...
- toohotatopic 6y agoWhat's the worst that can happen if all hydrocarbons are burned? At worst we are back in time where plankton and trees began absorbing the CO2 and turning it into oil and gas. In other words, nature will survive because such a state is well within the planet's capabilities. What am I missing?
- dTal 6y agoMost people regard human extinction as a Bad Thing.
- toohotatopic 6y agoWhy would humans become extinct? Somewhere on earth there will be a zone suitable for farming. At worst, only plankton and fish survive so some humans survive like Eskimos.
- dTal 6y agoSounds great.
- mjrpes 6y agoThe sunshade will be a good dry-run to solve the unavoidable problem of increasing sun luminosity in the far future, which is expected to disrupt plant life in 500 million years and ultimately destroy all life within a few billion years.