Today’s challenges to the sustainability of both our natural and social resources are different than they were 50 years ago. Global warming can make human life unsustainable, and the tensions of income inequality threaten the sustainability of the American democracy. But like generals fighting a new war with the weapons and strategies of the previous war, the natural resources and urban environmental movements have not yet adapted to these current threats.

Vanquishing the threat of greenhouse gas emissions will require more than the primitive alternative energy generators, composting our garbage, building only LEED-certified buildings and driving hybrid cars. We need to spend billions on “Manhattan projects” to invent new and much improved technologies to produce usable, relatively cheap energy sources that do not emit greenhouse gases.

A carbon tax will have to replace the complex cap-and-trade system to level the environmental playing field by cha