The response of business leaders to the problem of climate change is undergoing a major transformation. Even ten years ago, the corporate sector was almost uniformly opposed to serious government action on the issue. But increasing certainty about the science of climate change—and an ever greater understanding of the risks and opportunities it presents for businesses and society—have contributed to a new willingness among corporate leaders to help shape solutions. In addition to acting on their own to reduce greenhouse gas emissions, a growing number of businesses are calling for government action to protect the climate.