After a general introduction on climate change concerns, this paper discusses market failures involving products and services with an environmental footprint including in particular negative externalities. It argues that a consumer welfare analysis under competition or antitrust policy should take account of these environmental externalities, in all all areas of competition policy, including merger control, and antitrust assessment of horizontal and vertical agreements under Article 101(3) TFEU. The paper concludes that we can no longer afford to turn a blind eye to competition that exploits externalities that hurt the environment and the climate. Nor can we ignore the coordination problems that hamper solutions. Antitrust should be a part of an integrated climate policy, and the social cost of carbon emissions should be taken into account when assessing an agreement or conduct’s impact on consumer welfare.