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)

There is a growing movement advocating for using closed border policies as a tool for solving the climate crisis. On this view, which I call the green border argument, fighting climate change requires drastic reductions in the global population and/or per capita greenhouse gas (GHG) emissions. However, immigration into high-income countries—particularly from low-income countries—increases per capita emissions while leaving the population untouched. Therefore, the green border theorist argues, we should limit entry into high-income countries. I explain why this is a (...) mistake and why the political left should embrace a pro climate and pro migrant politic. -/- First, the argument significantly overstates the impact of immigration on global GHG emissions. Second, the progressive green border argument is normatively incoherent. It advocates for closing borders and eliminating poverty and other rights violations in sending countries. However, given the relationship between emissions and income, this argument would require rejecting all poverty reduction strategies—a conclusion the progressive theorist wants to avoid. Third, the argument is counterproductive. An open border politic better promotes climate justice. A key reason is that high-income countries perceive immigration to be one of the most serious short- and medium- term costs of climate change. Whereas closure allows them to avoid this “cost,” open borders would force them to eliminate push factors, incentivizing global adaptation and mitigation strategies. Moreover, a closed border politic creates divisions between those affected, undermining cross-border solidarity and contributing to the perception that environmentalism is a white, middle-class movement. (shrink)