if to look at civilization development through energy harnessed/controlled, our civilization has been through the following stages: 1. at human body energy lev

if to look at civilization development through energy harnessed/controlled, our civilization has been through the following stages: 1. at human body energy level by gathering/hunting (ie. what nature provided) 2. at human body energy level, managed/renewable. I.e. agriculture. 3. at industrial energy level by gathering - fossil fuels, nuclear fission. we're at the end of the stage 3. with stage 4. "managed/renewable industrial level" (solar/wind and nuclear fusion) appearing on the horizon. Increasing available energy levels allows for increased population growth. There is no limit in sight. The Moon and Mars are waiting :)