8000 years ago there weren't large cities with dozens of millions of people living in each one, many of them right on the coast. Humanity didn't need to grow en

8000 years ago there weren't large cities with dozens of millions of people living in each one, many of them right on the coast. Humanity didn't need to grow enough food to feed billions of people. There was no potential for large-scale modern warfare that can kill hundreds of million of people. We didn't depend on a wide array of advanced technologies and infrastructure -- which can be damaged, uprooted, or destroyed -- to support a relatively comfortable lifestyle for most people in developed countries. Incredibly rapid climate change has a much different impact now that it would have 8000 years ago. By the way, the science is pretty clear that then climate change happening today is far more rapid than anything that has happened in recent geologic history. I agree that spending 100% of our resources doesn't look to be necessary. But 5% or 10%? If this is what the science and engineering analysis tells us we should probably l do, then that seems like a rather responsible and beneficial course of action, given the known risks and the potential unknown unknowns.