I am weary of the crowd that keeps recycling the notion that our environment is simply incapable of sustaining us at our present level of consumption. Their answer to this, of course, always consists of transferring decision-making authority to those who fashion themselves fit to overcome such problems (assuming, of course, that they can get their mitts on state power to carry out their plans!). These people seem to be terribly ignorant of technological improvements in agriculture that provide exponential increases in food production. Nor do they seem curious as to how Hong Kong - a city with virtually no natural resources - manages to have one of the world's more successful economies. Neither do they seem to take into account the most obvious evidence of our sustainability: human population keeps increasing!
This song-and-dance has been around since at least the days of the ancient Greeks, who developed hemlock as a way of encouraging the elderly to die and cease being drains on limited resources that would be needed for the next generation.