The Oil Drum

One point is that all coal consumption will raise the earth’s temperature by about .3 degrees centigrade. All fossil fuels raise it about 1.7 degrees C.

This can not be true. Even now coal accounts for about the same CO2 emissions as oil (and catching up) and roughly twice more than Natural Gas. Here is a nice graph illustrating this:

Coal price per BTU is many times lower than the other FFs and hence its usage rises much faster recently. What is more worrisome are the ultimate coal reserves:

At the end of 2006 the recoverable coal reserves amounted around one exagram (1 × 1015 kg or 998 billion tons), approximately half of it being hard coal. The energy value of all the world's recoverable coal is 27 zettajoules, which is expected to last 164 years.[33] At the current global total energy consumption of 15 terawatt,[34] there is enough coal to provide the entire planet with all of its energy for 57 years

1 trillion tonnes of coal will emit 7-800bln.tonnes of carbon, or more than 100 years worth of carbon emissions at current emission levels. A rough calculation: if 50 years of burning FFs at about half current emission levels on average brought us 0.6C temperature rise, 100 years, twice that emissions should bring 4 times, or 2.4 degrees C temperature rise (forgetting about feedback loops etc.).

Even if we are pessimistic and half of that coal turns out unrecoverable, this is still 1.2 degrees or 4 times what your source suggests.