"to reach the 2-degree target the world would have to get CO2 out of its system by 2070. To reach the 1.5-degree target it would have to eliminate CO2 emissions by 2050."
Considering the already accelerating effects, tipping points already passed and coming up, and both internal and external positive feedback loops in melting ice and other realms, those are ludicrously optimistic dates. In truth, even if we stopped burning fossil fuels completely this afternoon, we'd still pass 2 degrees above preindustrial temperature well before 2050.
Our only rational course is to reduce fossil fuel use as fast as possible through a global climate mobilization like the industrialization of the US, 1942-45. Replacing fossil fuel infrastructure with efficiency, conservation, and more ecological lives; building clean, safe, resilient renewable energy; reforesting the planet; transforming global chemical industrial agriculture to networked local perennial plant-based permaculture; and transforming industry to benign, closed-loop, biomimicing ecological forms.