Inventing Climate Finance. From Incremental Costs to Strategic Ambiguity[Inventer la finance climat. Des coûts incrémentaux à l'ambiguïté stratégique]

How did "climate finance" become a distinct economic object? This paper traces the intellectual history of its construction from 1990 to 2024, arguing that economists did not discover a pre-existing reality but built the accounting categories — Rio markers, mobilisedprivate-finance methodologies, concessionality thresholds — through which climate-related financial flows were rendered measurable and governable. A computational analysis of approximately 30,000 works corroborates a three-act periodization: a prehistory when the concept did not yet exist (1990–2006), a crystallization triggered by the Copenhagen commitment (2007– 2014), and a period of disputes fought within the categories established during crystallization (2015–2024). Throughout, a recurring tension between an efficiency pole and an accountability pole runs through the field. Climate finance became governable not despite but through the deliberate ambiguity of its accounting categories — an ambiguity that was not a deficiency to be repaired but a political resource exploited by all sides.