I take your point, but arguably the optics of burning up every last drop of fossil fuel are worse.
Already, 96% of mammal biomass is humans and livestock. No one has the power to stop this process, to do what it would take. Enforcing a strict max-2 child policy on the whole world and/or telling people to live in the pods and eat the bugs. Hopefully, once our civilization goes interplanetary, we can try to restore a bit of what was lost.
Fertility rate is already below replacement for all of the world except sub-Saharan Africa, and it's dropping there too. We're headed for population decline within a century unless something changes dramatically.