We also need a cloud darkener in case the cloud brightener makes things worse.
Cue the Animatrix - The Second Renaissance Part II
We Could Brighten Clouds to Cool the Earth
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Re: We Could Brighten Clouds to Cool the Earth
#22Everything but taking care of the cause? Pollution. Deforestation. Etc. Here’s a good start: https://www.epa.gov/ghgemissions/global-greenhouse-gas-emiss...
It's not one or the other, as mentioned in the linked article. In any case even if all greenhouse gas emissions stopped today, which is not possible or even desirable, we'd still have a roughly 1.5 degree rise in average global temperature within the next couple decades. So, it's a question of whether we decide to live with the inevitable effects (the beginnings of which we're only starting to see) or do something about it. If the latter, what method balances effectiveness and safety in a scalable way, and marine cloud brightening is one of the best candidates for that.
Re: We Could Brighten Clouds to Cool the Earth
#23Earlier quoted context omitted.
Taking care of all of the causes is not enough to fix the problem of climate change. If we hit net zero today, it would still continue to warm for decades, which means more deforestation and desertification through fires. Your proposal is far too conservative to avert disaster.
Source? I think we would avert disaster if we got net zero today. We wouldn't avoid change and things would continue to warm as you say. But it wouldn't be the end of civilization, just very inconvenient. In the other hand if we don't stop making the problem worse we will eventually activate feedback loops that can't be stopped and that do end civilization, kill the majority of humans and other species, and make huge…
The IPCC special report on limiting warming to 1.5C is probably the best summary of ways to avoid catastrophe:
In particular, the figures in chapter 2 are particularly informative.
We are going to need to start sequestering carbon in the later part of this century, with as of yet unknown methods, but it's doable.
I would caution that climate scientists have been generally too conservative in their predictions, and there's substantial risk that they have missed something that could make warming much worse than we expect. (I would consider a 1% chance of much worse warming to be a substantial risk, I purchase insurance for far rarer risks than that.)
Additionally scientists have been overly optimistic about how much and how rationally society responds to the risks.
So in general I would say we are in somewhat worse shape than the SR1.5 report says, but there's no evidence of that, it's just analyzing the situation using standard risk modes rather than getting point estimates and confidence intervals on the best evidence.
Re: We Could Brighten Clouds to Cool the Earth
#24once the global climate gets sufficiently inconvenient we will definitely figure out a way of regulating ocean albedo via microorganisms or micromachines or something similar. human ingenuity will find a way. yes it might be a bit messy for a while...
What could possibly go wrong...
the bar is "less wrong"
Re: We Could Brighten Clouds to Cool the Earth
#25Wouldn’t that reduce the available sunlight for photosynthesis? The problem is that we’re trapping more heat per photon. Reducing the amount of photosynthesis might reduce the carbon fixation by plants. Not sure if that’d be a good idea.
The extra carbon in the air has already made plants more productive so there’s some offset already.
This seems plausible, but I'm curious if you have a citation?
Re: We Could Brighten Clouds to Cool the Earth
#26Wouldn’t that reduce the available sunlight for photosynthesis? The problem is that we’re trapping more heat per photon. Reducing the amount of photosynthesis might reduce the carbon fixation by plants. Not sure if that’d be a good idea.
Sounds like most of the brighter clouds generated would be over the ocean in this particular scenario, so shouldn’t affect plants too much.
"Scientists estimate that 50-80% of the oxygen production on Earth comes from the ocean. The majority of this production is from oceanic plankton — drifting plants, algae, and some bacteria that can photosynthesize"
Re: We Could Brighten Clouds to Cool the Earth
#27I think I'm a relative optimist about global warming because there are a number of possible climate engineering interventions which seem fairly cheap and could plausibly buy us another decade or so. I can imagine a future where perhaps India or China decides to act on their own to this effect, risks be damned.
All of the "climate engineering interventions" people keep trotting out that don't actually remove carbon from the air end up making things radically, disastrously worse.
We know how to remove carbon from the atmosphere, in bulk, with super-plentiful olivine. Cutting off emissions and deploying olivine works. Almost anything else ends up doing no net good, at best, and funnels us deeper into the hole.
Soluble iron compounds scattered over the open ocean could help. Any way to get the sulfur hexafluoride and HFCs out of the air would be an important contribution, because even getting CO2 content down to pre-industrial level would not be enough; those other manufactured gasses trap heat thousands or tens of thousands of times better than CO2 does, and are already a big part of the Problem.
Re: We Could Brighten Clouds to Cool the Earth
#28Wouldn’t that reduce the available sunlight for photosynthesis? The problem is that we’re trapping more heat per photon. Reducing the amount of photosynthesis might reduce the carbon fixation by plants. Not sure if that’d be a good idea.
The extra carbon in the air has already made plants more productive so there’s some offset already.
Invasive weeds and vines, mainly. Poison ivy, kudzu, and virginia creeper grow faster.
Most plants cannot use all the carbon they already get. Instead, they get less able to compete as the weeds choke them.
Re: We Could Brighten Clouds to Cool the Earth
#29Wouldn’t that reduce the available sunlight for photosynthesis? The problem is that we’re trapping more heat per photon. Reducing the amount of photosynthesis might reduce the carbon fixation by plants. Not sure if that’d be a good idea.
Photosynthesis is largely limited by water availability. Plants only uptake CO2 when they can open stomata, which is when they won’t dry out.
Photosynthesis is limited by the availability of light, water, co2 and warmth.
Re: We Could Brighten Clouds to Cool the Earth
#30We also need a cloud darkener in case the cloud brightener makes things worse.
The nice property of marine cloud brightening is that its effect goes away within weeks once you stop doing it. So if it turns out to have unexpected and unwanted side effects, we could just stop.