Disentangling the rhetoric of public goods from their externalities: The case of climate engineering

Public goods are defined by the technical conditions of nonexclusion and nonrivalry. Nonetheless, public goods are frequently viewed in environmental policy and scholarly debates as providing strictly positive benefits (or, in the case of public ‘bads’, providing strictly negative costs). We provide a theoretical understanding of heterogeneous externalities produced by public goods to challenge this assumption, by highlighting the ways in which a single public good can simultaneously produce positive benefits for some and negative externalities for others. To demonstrate our argument, we apply the theoretical framework onto the contemporary debates over climate engineering projects proposed to mitigate climate change. Such projects inevitably harm some countries internationally and some groups intranationally such that aggregate predictions about the benefits of climate engineering are misleading without an accurate accounting for its negative externalities.