2T/capita is extremely ambitious, but not inconceivable.
EDIT: By the way, it is notable that even before climate was a concern, CO2 emissions in developed countries were largely falling, since the 70s. This was a result of the oil crisis and other energy security issues pushing greater efficiency, plus the replacement of coal with gas for air quality and economic reasons.
There is no form of transport that will fix poor urban planning.
And it's _possible_ for public transport to work for fairly low density suburbs; I think some places have had success with small feeder buses feeding larger buses or trams.
Also, of course, urban planning can be improved. And tastes can change too; my impression is that the very large McMansion type houses are getting somewhat less popular in the US now, and they're a big contributor on two grounds (they exacerbate the low density problem, and they're expensive to heat and cool both due to sheer size and to generally relatively cheap construction prompted by the sheer size).
This is what I was sceptical about, but I haven't looked at these kinds of projects yet. I will 'research' more in to it. Thank you for these directions.
This isn't an obstacle, given electric cars and clean electricity generation. As I said elsewhere, nuclear is the only viable answer. Sadly, it has been demonized, and that needs to be reversed.
ThorCon's efforts in Indonesia will be interesting to watch. I'm not sure I like its current plan of siting the reactors like oil platforms in coastal waters though...
The best approach is underground siting, with no or very little water cooling requirement.