Abstract
Background: Climate finance is widely presented as the principal lever for accelerating renewable energy deployment, yet the empirical basis for that claim has not been assembled systematically. Global climate finance reached USD 1.9 trillion in 2023 and renewable energy investment USD 807 billion in 2024, but roughly 90% of that investment remained concentrated in advanced economies and China, and the field has grown so rapidly that its quality is difficult to appraise informally.
Objective: To map the research literature linking climate and green finance to renewable energy, and to synthesise, without statistical pooling, the empirical evidence on whether measured climate or green finance is associated with renewable energy deployment, renewable energy investment or the cost of financing renewable energy.
Methods: Openly accessible sources were searched on 30 June 2026: Europe PMC, PubMed/MEDLINE, the Directory of Open Access Journals, arXiv and Crossref. Scopus, Web of Science, EconLit and other subscription databases were not searched because access and exports were unavailable. Eligible reports were peer-reviewed empirical studies published between 1 January 2000 and 30 June 2026 that estimated a quantitative association between a directly measured climate or green finance exposure and a renewable energy outcome. Records were deduplicated, prescreened with a prespecified rule-based filter, and screened, extracted and appraised by one reviewer. Risk of bias was assessed with a seven-domain instrument adapted for observational econometric designs. Synthesis was structured and narrative, following SWiM principles; no pooled estimate, heterogeneity statistic or summary effect was calculated. Confidence in the body of evidence was assessed with an explicitly labelled structured framework rather than GRADE.
Results: Of 7,469 records identified, 4,894 were unique, 1,407 were screened, 431 were sought for retrieval, 75 were assessed in full text and 12 studies met the eligibility criteria. The screened corpus grew from single-figure annual counts before 2010 to 417 records in 2025, with 270 in the first half of 2026; 846 of 1,407 records had no recorded citations, and 19 retraction-related records were identified. Eleven of the 12 included studies reported an association favourable to renewable energy outcomes and one reported no statistically significant unconditional association. Reported estimates were heterogeneous in metric and scale, ranging from a green bond coefficient of 0.158 for renewable energy investment across 16 emerging Asian economies to an increase of 11.5–15.3 percentage points in the renewable share of final energy consumption following fossil fuel finance restrictions in 128 countries. Seven studies were judged to be at moderate risk and five at serious risk of bias. Seven of the 12 studies concerned China.
Conclusions: Openly accessible empirical evidence is directionally consistent with the proposition that climate and green finance are associated with greater renewable energy deployment and investment, but confidence is low. The evidence is geographically narrow, dominated by aggregate observational designs with limited identification, measured through incommensurable exposure indices, and set within a literature showing detectable integrity problems. The finding that one study reported a null unconditional association that became positive only when conditioned on financial development suggests that absorptive capacity, not finance volume alone, may be decisive. These results should not be read as establishing that climate finance causes renewable energy deployment.