Ha! You sort of slid a miracle in there like it was a checkbox. "We all have to change the way we live and quite possibly even the way we organize society ..."
Your solution to this problem involves Universal Agreement and Cooperation Among Humanity. People can't even agree not to murder each other.
Any solution which requires UAaCOAH might as well have unobtanium as its focal point. It's just not going to happen. We can't agree on metric versus imperial, on language, on such weirdly silly things like an afterlife, on oppressive things like what women should be allowed to wear (in the face of the collapse of the biosphere, right now, you can find interviews with men who have chucked acid onto the faces of their wives because their peers taunt them about said wives wearing modern and "immodest" clothing: a real top priority for civilization). We can't agree on who owns what rock and we can't agree on how to govern, and our governance can't agree with its populace on little things like not lying to them about practically everything.
We are a divisive, fiercely independent species with our own thoughts about everything, however trivial, whether or not it is good for us.
Forget three nines, ignore a couple of standard deviations, getting even four-fifths of humanity to suddenly snap on to an agenda which will be personally uncomfortable to them is too much to ask. Any plan which requires that level of agreement is absolutely doomed unless you've got some kind of high-level AGI in your pocket with just one priority: stop the oncoming several catastrophes valued over the preferences, choices, comfort, even reproductive lives of each person on the planet ... and some way of enforcing it. Lacking Forbin and his Colossus, we will not unite on much of anything besides "we all want to do what we individually want."
Once you realize this, it's going to be the small (in terms of populace) projects which do not require universal consent which might have any shot whatsoever, rather than getting the bulk of humanity together, for the first time in history, to cooperate.
Your solution to this problem involves Universal Agreement and Cooperation Among Humanity. People can't even agree not to murder each other.
Any solution which requires UAaCOAH might as well have unobtanium as its focal point. It's just not going to happen. We can't agree on metric versus imperial, on language, on such weirdly silly things like an afterlife, on oppressive things like what women should be allowed to wear (in the face of the collapse of the biosphere, right now, you can find interviews with men who have chucked acid onto the faces of their wives because their peers taunt them about said wives wearing modern and "immodest" clothing: a real top priority for civilization). We can't agree on who owns what rock and we can't agree on how to govern, and our governance can't agree with its populace on little things like not lying to them about practically everything.
We are a divisive, fiercely independent species with our own thoughts about everything, however trivial, whether or not it is good for us.
Forget three nines, ignore a couple of standard deviations, getting even four-fifths of humanity to suddenly snap on to an agenda which will be personally uncomfortable to them is too much to ask. Any plan which requires that level of agreement is absolutely doomed unless you've got some kind of high-level AGI in your pocket with just one priority: stop the oncoming several catastrophes valued over the preferences, choices, comfort, even reproductive lives of each person on the planet ... and some way of enforcing it. Lacking Forbin and his Colossus, we will not unite on much of anything besides "we all want to do what we individually want."
Once you realize this, it's going to be the small (in terms of populace) projects which do not require universal consent which might have any shot whatsoever, rather than getting the bulk of humanity together, for the first time in history, to cooperate.