 Since the adoption of the 2015 Paris Agreement and the publication of the 2018 Special Report on Global Warming of 1.5°C of the Intergovernmental Panel on Climate Change, net zero targets have become a central feature in climate policy. This perspective looks back at the scientific foundations of this recent policy development, the current state of play, and next frontiers for research on this topic. This article was authored by Uri Rogelge.