A population with that birthrate halves in of forty-five years, and then halves again in the next forty-five years. In one formulation, that means more resources per person—good news both for the people and the resources. But from another angle, it could mean perpetual economic crisis, which would be terrible news for the environment. In an economic crisis, there is neither money nor attention for responsible stewardship. There is no long-term thinking or action. Wars become more likely, and wars are deadly for the environment.
Possible to see this reaction happening in real time. Oil shocks following the invasion of Ukraine have already led the Biden Administration to authorize another round of fossil fuel projects.