In terms of energy, certainly. Generate electricity with non-carbon sources, then use electricity. The main difficulty would be aviation, because current batteries are too heavy, but there you could use biofuels until someone comes up with something better.

You're left with things like concrete that emit CO2 from something other than burning fossil fuels. But none of those things are strictly required. There are alternatives to them with various trade offs. Some that are essentially a drop-in replacement, basically different kinds of cement that don't emit CO2, others that operate differently but get you the same result, like using entirely different building materials. The main reason these aren't already used is cost, but that doesn't mean you can't pay the cost, it just means nobody is going to do it voluntarily. It also doesn't mean that no one could come up with some new alternative with a lower cost going forward -- that sort of thing happens all the time.

Not entirely, but a considerable portion can. However, the modern supply chain has to be fully tracked down first, to uncover exactly where most emissions are coming from, and then focus on understanding how to decarbonise those sectors as much as possible.