By that logic, no human activities are problematic since everything needed to sustain them comes from nature and eventually goes back to it. That's ignoring the

By that logic, no human activities are problematic since everything needed to sustain them comes from nature and eventually goes back to it. That's ignoring the tons of wastes generated by the beef industry, the ravaged ecosystems to make room for pastures and farms, the fuel needed to build and power the machinery to manage it all: from tractors to cargo boats to factories to trucks... The issue is that all that carbon and other mineral resources we dug up to power all of this ends up rapidly upsetting the balance the Earth settled in over the last million years. My point is that we could eat the same amount of calories by generating much less waste and needing much less space and energy.