Both culturally and genetically, human beings have always been small-group animals, evolved to deal with at most a few hundred individuals. Humanity is suddenly (in ecological time) faced with an emergency requiring that it quickly design a governance and economic system that is both equitable and suitable for a population of billions, and sustainable on a finite planet. Earth is now so overpopulated that it would require something like five more planets to support permanently today’s global population at the average American lifestyle, and yet several billion more people are scheduled to be added to the population by mid-century, even though several billion are now living in misery. Humanity is exhausting its natural capital: deep agricultural soils, fossil groundwater, and the biodiversity that runs its life-support systems. It is disrupting the climate, spreading toxic chemicals from pole to pole, increasing the chances of vast epidemics, and risking nuclear war over resources, especially water. And the scientific community fears that at most a decade or two remain to revolutionize our energy mobilizing systems (still extremely dependent on fossil fuels) and revise our agriculture and water-handling systems to enable them to respond to the centuries of changing precipitation patterns predicted by climate scientists. Any chance of growing enough food to give a decent diet to all of today’s population requires success in these endeavors. Creating a just society, in which care for each other and our life-support systems moves to the top of the political agenda, depends on social movements such as Occupy Wall Street.

The capitalist economic system traces back to the agricultural revolution, when families first became sedentary and were able to produce more food than they consumed. That laid the groundwork for a division of labor that led to priests, soldiers, politicians, commissars, rulers, entrepreneurs, Wall Street parasites, scientists, and a period of unprecedented growth of the human enterprise. A combination of markets, private ownership, and the organization of corporations has led to enormous riches for the few and prosperity for a substantial minority of humanity. But collusion among capitalists (anticipated by Adam Smith), and an insane belief that physical economies can grow forever (a myth that is endemic to both politicians and second-rate economists) have led to an extraordinarily threatening global environmental situation. The most immediate threat is to poor people and poor nations, although in the end the rich will fall further because they have more to lose.

It is clear that we must redesign governments to regulate the marketplace so that most externalities are internalized for the good of society. Everyone should recognize that old-time capitalism, like socialism and communism, simply has not and cannot generate the sustainable redistribution and material and population shrinkage that are essential to creating an environmentally sound and equitable global society. The challenge is immense and unprecedented, with the dilemma exacerbated by plutocrats buying politicians and funding a powerful and effective disinformation machine programmed to lie about environmental threats. Overcoming that machine will require much cooperation, which won’t likely be achieved without new institutions and a broad increase in social justice. And these will require what the Occupy movement apparently demands: that we step back and consider whether the society we’ve built is indeed the one we want. But we have no choice but to meet the challenge. Either we will change our ways, or they will be changed for us.