According to the American Academy of Pediatrics:

Climate change threatens to reverse the gains in global child health and the reductions in global child mortality made over the past 25 years. There is broad recognition that greenhouse gases emitted by human activities are causing climate change. The problem of climate change transcends geopolitical boundaries and will have extensive impacts on child health and security. With implications for all of humanity, climate change will disproportionately affect children and the poor, magnifying existing disparities in social determinates of health.

I don’t know if “reverse” means we stop making gains, or if child mortality rates actually revert to where they were 25 years ago. Either way, it kind of suggests the amazing progress of recent decades may have peaked, at least for the time being.