One big worry, when it comes to how much climate change humanity will experience, is the possibility that economics or concerns about energy security could drive states with ample coal reserves to convert those into liquid fuels. Coal-to-liquid (CTL) technology has existed for a long time, and was used by Germany and Japan to fuel their military equipment during WWII, when blockades made access to outside oil fields constrained. The chemical process through which they did so is known as the Fischer-Tropsch process.
That CTL risks doing is accelerating the pace at which the massive amount of greenhouse gas trapped in the world’s coal reserves gets released into the atmosphere. It also risks increasing the total quantity of coal that gets burned, before humanity finds ways to live in a carbon neutral manner. Converting coal into liquid fuels is also a capital and energy intensive process. While the energy requirements will further increase emissions, if the energy inputs come from fossil fuels, the high capital costs also risk diverting investment away from genuinely sustainable options like wind farms and concentrating solar power facilities.
Like palm oil grown in areas of former rainforest, CTL fuels are potential replacements for gasoline and kerosene that are actually far worse for the climate than the conventional fossil fuels they replace. Those who are concerned with just how dangerous climate change may be for humanity ought to keep the dangers associated with them in mind.