Wow. Only enough reserves to be measured in decades? Once it's gone it's gone. Genuine Carboniferous coal, one day a thousand years from now, might be a rare museum item!
I have a habit of thinking about history in very long terms, and that just does not sit right with me. That kind of thinking (oh we have enough for decades, let it rip!) happens, and the decades pass, and time inevitably is less kind to the descendants of such decision makers.
growing up (in the 70s/80s), the first time I was shocked at the exponential destructiveness of human civilisation was when I learnt that we had polluted the oceans. the second was when I found out that ubiquitous natural resources like oil could be completely consumed. I feel like either one would have been unthinkable even as late as 1900.
(incidentally the latest such shock was sometime this decade when I learnt that an aquifer could not only be depleted, but that that depletion would compact the soil so that it would thereafter be unable to hold water, and thus never (at least on our timescales) be able to be replenished. I think I'm still not over that!)