[thomasahle]

> My prediction is that geo-engineering will be done when a certain death/disturbance threshold will have been reached

People seem to be accepting "the new normal" very fast. I'm not sure geo-engineering will be popular, since the status quo bias that's currently preventing us from reducing fossil fuels, will also stop any "artificial weather manipulation".

[Timon3]

But let's be fair - "reducing fossil fuel consumption" and "artificial weather manipulation" are on completely different levels in regards to dangers. Nothing bad will happen if we suddenly stopped all fossil fuel consumption and replaced it with renewable energy. We don't know what kind of bad things can happen with artificial weather manipulation, because we haven't really done that before, and you can't really test the impacts in a closed experiment.

[phreeza]

I think it's not really clear that nothing bad would happen if we stopped fossil fuel consumption right now. It would be pretty massive perturbation on a complex system. I think we should still do it because the alternatives are even worse, but let's not kid ourselves into thinking there are risk free paths out of the pickle we are in.

[Timon3]

It seems reasonable to me to assume that nothing bad would happen if we stopped fossil fuel consumption right now. The ecosystems on our planet have only had fossil fuel emissions added for around 200 years, and in that time these emissions have had a very negative effect on the whole system. If we stop adding these we return to the normal which has been ongoing for millions of years. It's not a perturbation, it's stopping a perturbation.

By what mechanism would you expect something bad to suddenly happen?

[phreeza]

The whole point is that it is hard/impossible to predict, and I am even hesitant to list some ideas because they sound like climate denier conspiracy theories. But just as a hypothetical example, there may be effects from aerosols ejected along with CO2 when burning fossil fuels, which act on shorter time scales in the opposite direction, which could lead to overshoot.

[Timon3]

> The whole point is that it is hard/impossible to predict

But it certainly seems much easier to predict compared to the results of further CO2 in the atmosphere. We've lived through the transition period from lower CO2 to current CO2, so it's reasonable to assume we'll see the same effects in reverse. We haven't lived through the period of current CO2 to higher CO2.

> and I am even hesitant to list some ideas because they sound like climate denier conspiracy theories

Understandable, no worries!

> But just as a hypothetical example, there may be effects from aerosols ejected along with CO2 when burning fossil fuels, which act on shorter time scales in the opposite direction, which could lead to overshoot.

Sure, it's possible, but it seems much more likely that continued increases in CO2 will have worse unpredictable effects.

[phreeza]

> Sure, it's possible, but it seems much more likely that continued increases in CO2 will have worse unpredictable effects.

I completely agree.

[AnimalMuppet]

By the mechanism of starvation. You can't produce (and distribute) the amount of food that we need without the use of fossil fuels.

Up-thread, you said "and replaced it with renewables", but we can't do that right now.

Bluntly, if we hard-stop the use of fossil fuels today, a large chunk of the human population are going to die.

[Timon3]

Yes, if you change the parameters of my hypothetical, the results change. What's your point?

[AnimalMuppet]

I thought I was adequately clear. If you need me to make my point more clear, here you go:

> > > It seems reasonable to me to assume that nothing bad would happen if we stopped fossil fuel consumption right now.

For what most people mean by "right now", something bad happens - many, many people die. You chose that phrase; I didn't. So within the normal meaning of the phrase, you are very wrong.