Global Climate Science Imperatives in a Post-Paris Agreement World

The historic 2015 Paris agreement (COP21) created a greenhouse gas control framework for nations to reduce emissions and contain global warming. It empowers nations to set voluntary reduction targets, promotes a low-carbon economy, and encourages transparent emissions reporting. Above all, it sets up a dynamic process to strengthen targets as energy systems mature and the pace of climate change is better quantified. COP21 presents opportunities and challenges for climate science. Our planet’s greenhouse gas trajectory is determined by the complex interplay of societal actions and Earth system responses to climate change. Policymakers need information about the rate and magnitude of climate change, as well as the efficacy of emission-reduction measures, to adapt and act iteratively to adjust greenhouse gas targets. Forests and oceans presently soak up half of carbon dioxide emissions, but this fraction varies significantly year-to-year and may weaken over this century. Furthermore, expansion of some energy exploration, such as tight shale gas, can increase regional emissions. The problem is compounded by the potential release of greenhouse gases from the thawing Arctic. This session highlights how atmospheric observations and inverse analysis of greenhouse gases and their isotopes are transforming our ability to constrain local, regional, and global fluxes. The panel focuses on the goals of advancing global greenhouse gas analysis systems and emissions reduction policies on multiple scales.