An antitrust paradox lies at the heart of private-sector climate commitments. On the right, state attorneys general have warned that they may challenge these collaborations under antitrust laws. On the left, antitrust enforcers in the Biden Administration asserted that these actions will not receive preferential treatment even if they address societal ills that are not being addressed by governments. This Article asks what antitrust law is willing to consider: if prosocial goals are framed in terms of economic harms, should antitrust law view climate action as violating that standard? It argues that the avoided harms to the economy and consumers from emissions reductions can yield economically cognizable consumer welfare enhancement in the longer term, and that climate action thus is defensible under current antitrust doctrine.