Deforestation also is having major effects. Look at the Northern Hemisphere summer drawdown of Carbon Dioxide. Can come down quick. Deforestation in the Southern Hemisphere is a big problem. If Australia wanted to make a significant contribution they would stop land clearing and cutting down our native forests.
Fossil fuels, are just that: fossils. They will be completely depleted within a few decades at most. We are already a decade past peak oil. Might be better to preserve some to use as chemical feedstocks for things like fertilizer and plastics. Burning them is pretty stupid at this point.