The debate about greenhouse gases is heating up. Across a wide spectrum, some voices argue that emissions and climate aren’t linked, while others urge immediate concerted global action to reduce the flow of emissions into the atmosphere. Even the advocates of action disagree about timing, goals, and means. Despite the controversy, one thing is certain: any form of intensified regulation would have profound implications for business.

Our contribution on this topic is not to evaluate the science of climate change or to address the question of whether and how countries around the world should act to reduce emissions. In this article we aim instead to give policy makers, if they choose to act, an understanding of the significance and cost of each possible method of reducing emissions and of the relative importance of different regions and sectors. To that end, we have developed an integrated fact base and related cost curves showing the significance and cost of each available approach, globally and by region and sector. Our other purpose is to help business leaders understand the implications of potential regulatory actions for companies and industries. Indeed, regulation is already on the minds of many executives. A recent survey¹ indicates...