He said "Some people say growth can't happen forever, and all growth comes at environmental cost". Pointing out that "Every economic output requires material inputs" doesn't mean that there are limits to growth or that you can't have growth without environmental cost.

As an example, if you have a resource that you consistently get more efficient at operating, you can consistently use it to provide more and more value to the world (economic growth).

To use his example: if you take a human who would be using material inputs like food, and instead of them engaging in activity that did not provide value to society, they spent their time giving people massages, you have not increased the amount of physical resources being consumed (since the person was otherwise using the same amount of resources, just not doing anything of value).