Current international climate frameworks predominantly rely on the Global Warming Potential over 100 years (GWP100) to assess and compare the impacts of greenhouse gases. However, this approach substantially undervalues the climate benefits of mitigating short-lived climate pollutants (SLCPs) such as methane, responsible for nearly 45% of current net warming. The lower warming potential assigned to methane under the GWP100 reduces both policy urgency and financial incentives for rapid mitigation.

This policy brief explores the potential of adopting a 20-year GWP (GWP20) metric as the basis for pricing methane credits within a dedicated voluntary carbon market in G20 countries. By reflecting methane’s true short-term climate impact, GWP20 can serve as a catalytic market signal to accelerate action on methane mitigation, generating significant near-term climate benefits, unlocking new finance, and contributing to multiple Sustainable Development Goals (SDGs).

Recognising that no single metric is universally sufficient, the brief also outlines a phased roadmap: first, integrating GWP20 into targeted market mechanisms; and subsequently evolving towards a holistic, inclusive, and science-aligned radiative forcing-based accounting system. Policymakers are also encouraged to promote data-driven tools, such as the Carbon Credit Data Model, to better capture and communicate the real-time climate effects of SLCPs.