The historic agreement forged in Paris among 195 countries in December holds the promise of triggering a global shift to combat climate change—and harbors a hidden warning.
Regardless of what happens next, the Paris accord is a triumph of diplomacy among nations that have starkly disagreed in years past about who is responsible for cutting carbon dioxide emissions—and who should bear the cost. But success in heading off the worst climate disruptions hinges on whether countries fulfill the pledges each made leading up to the Paris talks and make bolder ones this decade. The teeth come in the form of sunshine and shame: The accord requires transparency and monitoring of emissions from each country. And it relies on countries to be motivated by the ignominy they would face if they reneged.