To stay within the 1.5 to 2ºC bounds, the IPCC already includes massive carbon sequestering technologies in even its most simple recommendations. This is technology that does not exist. We're betting life on Earth (and truly, it is that dire) on tech that might be impossible to build and scale. Even if we reduce our carbon emissions to 0 today the delayed effects and non-linear dynamics are so poorly understood, that it could very well be that nothing truly can be done to avoid our mass extinction. And, this too goes for carbon sequestering; even if we magically suck the last 5 decades of carbon out of the air, some stuff that is broken can't be fixed. Thresholds, catastrophes, oscillations, bifurcations, etc are real. We really have to think in non-linear systems when dealing with climate, and that is something we're very bad at. Especially when it comes to the media-voter complex. But picture this, you are driving your car down some road, and everything is fine. You're minding your own business. There's nobody else there, so what the heck, let's ramp up some of the speed. And you go faster and faster. Until bam, unexpected steep corner, your car flies off the road and you die. At that point going back a couple of miles is never going to fix you. It's too late.