Double materiality is an extension of the key accounting concept of materiality of financial information. Information on a company is material and should therefore be disclosed if “a reasonable person would consider it [the information] important”, according to the US Securities and Exchange Commission
Thanks to the work by the TCFD, it is now widely accepted within financial markets that climate-related impacts on a company can be material and therefore require disclosure.
The concept of double materiality takes this notion one step further: it is not just climate-related impacts on the company that can be material but also impacts of a company on the climate – or any other dimension of sustainability, for that matter (often subsumed under the environmental, social and governance, or ESG, label).