Summary/Abstract
Geoengineering, which for purposes of this article includes carbon dioxide removal technologies, has been discussed as a technique to control anthropogenic global warming. Public Trust Doctrine (PTD) is used to hold assets that are not in private ownership in a form of collective ownership for public benefit; it is familiarly applied to the shoreline between tides. Several variants of PTD exist, yet all variants serve to limit private ownership. The version arising from Anglo-American common law creates duties and responsibilities on the sovereign to maintain and preserve assets in public trust. This article considers various types of geoengineering to protect example assets currently under PTD, finding a compelling case for action in a variety of contexts. This introduces a paradoxical situation, where it may theoretically be easier to compel states to undertake geoengineering to protect a beach, than to protect the whole planet. The article notes that, whilst PTD obligations are atomised in nature, the inherent commonality of the threat potentially serves to reduce this fragmentation, and to encourage common action amongst states. However, the article considers the failure of recent legal proceedings, which exposes practical limitations on the ability of PTD to compel climate action generally – and thus its applicability to geoengineering.