Quite an interesting and informative post.
I do feel that coal, oil and gas is a commodity that countries won't easily seperate from.
I'm from Nigeria and although we have other exports in agriculture, our already failing economy is still dependent on the dwindling crude oil wells.
Changing entirely to only agriculture would make the ecosystem which has already adapted to our constant rigging shift again to the now increased rate of farming.
Even if the change of export produce were to happen gradually, it's uncertain (personally, I feel impossible) for our country to adapt fast enough.
Maybe after a few generations...