The Carbon at Risk measure can unlock financial markets for large-scale carbon removal

In carbon removal markets, binary classifications like ‘permanent’ versus ‘non-permanent’ have emerged as practical heuristics but discourage investment just when we need it most. Drawing inspiration from Value at Risk in financial markets, we propose Carbon at Risk (CaR), a quantitative metric that harnesses collective risk assessment expertise to measure and compare climate outcomes of diverse removal projects. Implementation of CaR enables organisations to proactively identify risks and build resilient carbon portfolios through strategic protective measures. Credible CaR scores could also support international coordination on precise carbon accounting, helping policymakers to track carbon flows and direct finance towards projects with acceptable climate impact.