I hope that humanity doesn't grow until we actually have that room beyond Earth available to us. Martin Rees believes with a vegan diet, no travel and spending

I hope that humanity doesn't grow until we actually have that room beyond Earth available to us. Martin Rees believes with a vegan diet, no travel and spending most of the time in VR, Earth could sustain 20 billion people. We're already using resources in an unsustainable manner. Human greed will keep it that way. Now, once we have those O'Neill cylinders out there, sign me up! Just building a single one in space is going to require an incredible amount of resources, however.