Sustainability Science

More than 100 cities have pledged to run on 100% renewable energy and signed onto the Sierra Club’s “Ready for 100” campaign. But turning commitment into action is where the real work begins, and Atlanta might be the ultimate test case.

The Trump administration’s proposed freezing of tailpipe regulations would reverse one of the most effective climate actions on the books.

EPA officials raised multiple red flags in June about the administration’s contention that freezing fuel economy targets would result in fewer traffic deaths.

Several other countries have linked their fuel economy standards to the United States, so a rollback by the E.P.A. could affect rules across the globe.