"- environmental degradation is based on two exponential growth trends: human population and per-capita consumption (driven by economic growth)." You left out

"- environmental degradation is based on two exponential growth trends: human population and per-capita consumption (driven by economic growth)." You left out one detail: environmental degration per consumption. This is a really important factor, and is probably easist of th tree to minimize, and is being minimized every year. (Assuming that you didn't equate consumption and environmental degration).