Pre-industrial levels when we were still coming out of significant cooling period. In every other period of human history, increased average temperatures have

Pre-industrial levels when we were still coming out of significant cooling period. In every other period of human history, increased average temperatures have coincided with golden ages. Depending on where you peg your baseline for what "normal" temperatures are, the projections can look more or less scary. https://en.wikipedia.org/wiki/Roman_Warm_Period https://en.wikipedia.org/wiki/Roman_Warm_Period https://en.wikipedia.org/wiki/Medieval_Warm_Period https://en.wikipedia.org/wiki/Medieval_Warm_Period I'm suspicious of anyone attempting to boil down the operations of such a dynamic, chaotic system as climate into simple cause and effect. There's so damn many things that feed back on each other, and that's just the tip of the iceberg that we think we understand. Much more research needs to be done.