Climate change can be an existential threat to humanity and Geo-Engineering can make it worse at the same time.
If you knew you were going to die next week, what's to stop you from picking up smoking right now?
The truth is we don't need geoengineering because the truth is that it's not an existential threat for humanity, it's just the future is going to suck really hard for a lot of people if we don't get off our our collective asses.
Going around moaning "we're all doomed and there's no use trying" is exactly the opposite of what we need right now.
Look at it this way. Someone who is bitten by a rattlesnake is at risk of dying (an existential threat). Certain medical care, like giving the patient Advil or any other form of blood thinning pain killers could actually end up making matters worse which in turn could increase the chances of the patient dying.
No one here is saying we’re all doomed and there’s no use in trying. What they are doing is pointing out that carbon capture and geo-engineering may not be the most fitting solutions to this existential threat, and that these solutions could even potentially make matters worse.
>“How can something be worse than an existential threat?”
If something you do makes your chances of surviving an existential threat worse, the consequences of your actions could make the initial existential threat harder to manage and in turn make it more likely to succumb to said threat.