Given how impossible it is achieve global consensus on policy, I'm pretty inclined to believe that a technological breakthrough is the only solution. Maybe a series of them.
In the best case, carbon removal and sequestration tech.
In the neutral case, clean and efficient energy tech.
In the worst case, climate-catastrophe coping tech.
In the best case, carbon removal and sequestration tech. In the neutral case, clean and efficient energy tech. In the worst case, climate-catastrophe coping tech.