An essential part of the decarbonization challenge is proposing, analyzing, and comparing various legal pathways to that result in each individual country. Those legal pathways should be capable of reducing greenhouse gas emissions at a speed and scale needed to give the world its best chance of keeping the global average temperature increase below 2°C while also producing as many economic, social, environmental, and security benefits as possible. This Article, adapted from Chapter 2 of Contemporary Issues in Climate Change Law & Policy (ELI Press 2016), provides an overview of the challenge of achieving a zero-carbon future, as well as the way in which sustainable development would frame the decisionmaking process for doing so.