Climate change adaptation is becoming a financial asset. A global architecture of multilateral funds, catastrophe bonds, parametric insurance, and mixed financing transforms it into a tradable commodity and subordinates it to the logic of capital. My hypothesis is that Polanyian double movement, extrapolated to contemporary climate finance, allows us to answer under what conditions Latin American public banks protect adaptation from financial logic and when they transfer it to that logic. The objective is twofold: on the one hand, I propose the category of convergence of fictions to name the joint commodification of labor, land, and money through a single financial instrument; on the other, I formulate three conditions under which a public bank can operate as a containment circuit (substantive mandate, non-market criteria, and democratic governance) and apply them to seven banks. None of the Latin American banks meet all three. In Mexico, the legislation of the main development bank prohibits workers and affected sectors from serving on its board, which by design blocks deliberation with those affected by climate risk. Colombia offers available evidence that sub-legal redesign is feasible: a microfinance program for ecosystem-based adaptation, without a statutory clause or open governance. The text first develops the theoretical framework, then the comparative institutional diagnosis, and concludes with foreseeable objections and four lines of empirical research.