Boundaries for a Healthy Planet
Scientists have set thresholds for key environmental processes that, if crossed, could threaten Earth's habitability. Ominously, three have already been exceeded
Stories by David A. Vaccari
Phosphorus Famine: The Threat to Our Food Supply
This underappreciated resource--a key component of fertilizers--is still decades from running out. But we must act now to conserve it, or future agriculture could collapse
