Private finance has a vital role to play in the global response to climate change, but it is not a substitute for public finance. Developed countries have committed to mobilizing $100 billion in climate finance per year by 2020 to support climate adaptation and mitigation in developing countries. Reliance on private finance over public to meet these financing goals presents a triple whammy for pro-poor adaptation. Private finance will struggle to meet the essential adaptation needs of poor and marginalized people; it overwhelmingly favours mitigation over adaptation; and it favours richer developing countries over less developed countries. COP19 in Warsaw in November 2013 must turn ambiguity into action by advancing strategies to scale-up public finance for adaptation, and by providing assurances that commitments to critical support for the world’s poorest countries and communities over the coming years will be met.