Every year, an untold number of species either die off or become endangered. This is mostly thanks to a mix of human-led factors that scientists call HIPPO–habitat destruction, invasive species, pollution, population growth and overhunting–and it may well have dire consequences for our species and our world at large. To buck this trend, Pulitzer Prize winner Edward O. Wilson suggests humans take a drastic measure: devote fully half of the earth’s surface to nature reserves. This wouldn’t mean abandoning entire continents, but it could mean asking people to consider selling or trading their land to create reserves large enough to support rich ecosystems. “As reserves grow in size,” he explains, “the diversity of life surviving in them also grows.” Of course, Wilson acknowledges, there are commendable conservation efforts already under way, and communities might be reluctant to make the sacrifice he suggests. But as “the mind and stewards of the living world,” he writes, humans have a responsibility to “do no further harm to the biosphere.”
This appears in the March 14, 2016 issue of TIME.