Scholars of environmental law are gaining comfort with looking for law in unusual places. As a result, lists and maps of the environmental content of contractual provisions are emerging. What these lists and maps largely miss, however, is the powerful dynamic of how legal norms move across borders through contract. This article argues that contractual provisions operate as critical platforms for the migration of legal norms, ideas and technologies between project and transactional settings. Three dynamics of how this movement takes place (transfer from contract to contract, migration from contract to legislation, and entrenching private standards through contract) are explored – each revealing how contractual practices reproduce selective visions of what counts as the ‘environment’ worth protecting.

Transnational environmental law is the subject of growing scholarly interest. Yet, much work remains to be done to fill in both the conceptual and empirical contours of this field. One methodological challenge that transnational law poses is the need to look beyond traditional sources of international and national law. This article contributes to efforts to understand transnational law's multilayered architecture by drawing attention to the use of transnational contracts as a mechanism to protect habitats and species. The diverse and proliferating examples of conservation contracts discussed in this article – which include forest carbon agreements, conservation concessions, debt-for-nature swaps, conservation performance payments, and private protected area agreements – reveal an ongoing and intensifying transnational attempt to use private contracts to address some of the most pressing issues of common concern. This article draws on fairness theory in both contract and international environmental law to argue for law's relevance in interpreting conservation's call for contracts.