People are already working on all of those things.

Even with coal electricity, electric cars have lower total-lifetime CO2 emissions.

Also, the more low-hanging fruit we fix, the more time we have left for the hard stuff.

Most of these things are one time investments (plus maintenance), which you need for non-renewable energies just as well (and one might argue that building oil rigs and refineries and transporting the fuel is more CO2 intensive than windmills and power cables).