The operationalization of new funding arrangements for assisting developing countries that are particularly vulnerable to respond to loss and damage is underway within the framework of the Paris Climate Agreement. In this context, key questions have to be addressed regarding the allocation of funds and recipients and how vulnerability to climate change will be factored into decision-making processes. This Study analyses evolutions in defining vulnerability across different domains: the scientific (IPCC), legal (UNFCCC), and financial (multilateral funding mechanisms), in order to better understand implications for Parties to the United Nations Framework Convention on Climate Change and find potential avenues forward around this polarised issue.