Can global emissions really be reduced?

Prompted by David Hone (“bonkers”, says NB :-). But it says something that I’ve been thinking for a bit, and haven’t seen anyone else say:

Arguably, we are in a time where underlying global energy demand exceeds supply. This isn’t to say they are out of balance as that is not possible, but it says that if there were more energy then global economic growth would be even faster. This condition could well persist for a long time given population growth and the rapid expansion of several major economies – with more to follow. A direct implication of this thinking is that the production of all fossil fuel energy is infra-marginal, i.e. there is nothing at the margin and that even the most expensive to produce barrel or tonne on the planet is profitable at current price levels.

Now I’m not entirely sure about his economics there, but I do think his basic point is either true or close-to: that for a lot of fuels, oil most obviously, use is limited by production. If we (we? The West, say) limit our use by being nicely green, then someone else is going to burn it instead. I’m not saying “and therefore we should do nothing” but it does present a problem.