Many of the world’s largest firms have announced plans to reduce their carbon emissions over the coming decades. Against the backdrop of stuttering climate policy, this development is widely held out as positive. So far, such announcements are largely hortative, with nothing to stop companies from failing to deliver. However, we now know that a growing proportion of investors are climate-conscious: that is, their valuations depend not simply on classical financial models, but also on firms’ actual and proposed levels of carbon emissions. We show that as the volume of climate-conscious capital grows and associated investment strategies increase in sophistication, firms will face increasing incentives to make their emission commitments credible. We also show that mechanisms commonly proposed to accelerate corporate transition to low emissions – such as climate disclosures, corporate governance reforms, or changes to the corporate purpose – are inadequate to deliver credible commitments. Instead, we propose a suite of contractual mechanisms, which we term 'green pills', to make climate commitments credible by endogenizing incentives to meet climate targets. We argue that their adoption is consistent with directors’ fiduciary duties and requires no change to corporate law. Green pills can thus help firms and their investors undertake credible climate commitments and show other stakeholders whether firms really are serious about their contribution to tackling climate change
