A comparative review of methane policies of the United States and China in the context of US – China climate cooperation

Methane is a powerful greenhouse gas. The US and China are the world's two of the largest methane emitters and jointly committed to tackling this global challenge in the US–China Joint Glasgow Declaration at COP26 in 2021. However, few studies have revealed the methane policy landscape in the two countries. Greater understanding of these policies and how they have evolved is critical for enhancing future actions. We addressed important research topics currently understudied, including the types of policy instruments used, the commonalities and differences between the two countries in their primary policy foci, and the evolution and driving forces of methane policies. This study conducted a comprehensive and comparative review of methane-related governance structures and policy frameworks in both countries. We performed policy mapping based on systematic and large-scale policy document collection and screening, followed by an in-depth review of the development of methane policies in both countries. This study found that both countries placed uneven emphases across sectors, with a notable focus on the energy sector. While the US showed a preference for regulatory policy instruments such as acts, rules and regulations, China primarily utilized planning instruments such as Five-Year Plans (FYPs), notices, and working guidelines. Additionally, methane policies in both countries were largely driven by safety, resource utilization, and pollution concerns rather than reducing greenhouse gas emissions. Our study suggests that both countries should fill the policy gaps to accelerate their actions on methane mitigation and consider more climate-centric policies. It underlines the potential for US–China collaboration through the exchange of knowledge and best practices, which would also greatly advance global climate governance.