James Hansen has coauthored a new paper on oil and climate. He has posted a note explaining that:
The principal conclusion of this paper is that it is possible to keep atmospheric CO2 at a much lower limit than commonly assumed, provided that coal use is phased out except where the CO2 is captured and stored, and use of unconventional fossil fuels, if it occurs, is also accompanied by CO2 capture and storage.
Needless to say, liquid coal is a nonstarter. Here is the abstract: