You'll remember that when we talked about the Industrial Revolution, we discussed the virtuous cycle of more efficiency making things cheaper, which in turn made them easier to buy, which increased demand, which increased efficiency. But from the perspective of the planet, each turn in that cycle takes something. More land under cultivation, more carbon emissions, more resource extraction. That can't go on forever, but worryingly, our current models of economic growth don't allow for any other way. Thanks, Thought Bubble. And then there is our astonishingly robust health. Although much of the world has been ravaged by HIV-AIDS for the past three decades, there's been a relative lack of global pandemics since the 1918 flu.