Conservation biologists agree that humanity is on the verge of causing a mass extinction and that its primary driver is our immense and rapidly expanding global economy. We are replacing Earth’s ten million wild species with more of ourselves, our domesticated species, our economic support systems, and our trash. In the process, we are creating a duller, tamer, and more dangerous world. The moral case for reducing excessive human impacts on the biosphere is strong on both anthropocentric and biocentric ethical (...) grounds. The sine qua non for doing so is reducing human numbers and the size of our economies, while increasing the global acreage set aside in protected areas. We should take these steps as part of comprehensive efforts to create just and sustainable societies in which both humans and other species can flourish. (shrink)