Start looking at how all the replacement transportation can be put in place 11 years - either getting all cars off the road, and manufacturing new electric ones; or building other mass transit that can serve everyone (and how long does it take to get a train line built these days?). How are we going to find enough building contractors to install electric heat or heat pumps into every house that uses oil or gas, and to build and install electric stoves?
And of course there's the upheaval of jobs for all the people in the current industries, and trying to find a place for them in the new industries.
Money's not the bottleneck here, we're more constrained by logistics.