With COVID letting it become so widespread with not enough protection before the vaccines, means that more people got the disease, the virus got more opportunities to mutate, and new strains are coming out, some of which could be more fatal or maybe resistent to vaccines. Getting late may makes it harder to solve, if possible at all.

With global warming is worse. Is not just stopping emissions, but what we already emitted is already driving the change. And positive feedback is already being triggered, with less albedo because less ice in the north pole, methane emissions in northern places like Siberia and Canada, and each time more frequent/bigger forest fires. So to slow it down you don't just have to capture the equivalent of what we emit (100k barrels/day makes a lot of greenhouse gases, think in 0.5-1 ton of greenhouse gases per barrel, and you have coal and others to take into account too), but also the amount we already emitted, and what comes from positive feedback (that eventually could become orders above of what we emit).

And I'm talking about greenhouse gases, not heat in particular, you are not dealign directly with warming addressing the gases, so that is something that should be taken into account regarding mitigation.