Cost-effective implementation of the Paris Agreement using flexible greenhouse gas metrics

摘要: Greenhouse gas (GHG) metrics, that is, conversion factors to evaluate the emissions of non-CO2 climate forcers on a common scale with CO2, serve crucial functions upon implementation Paris Agreement. While different metrics have been proposed, their economic cost-effectiveness has not investigated under range pathways, including those temporarily missing or significantly overshooting temperature targets Here we show cost-effective for methane minimize overall cost mitigation are time-dependent, primarily determined by pathway, and strongly influenced overshoot. The Agreement will implement conventional 100-year Global Warming Potential (GWP100), good approximation coming decades. In longer term, however, suggest parties consider adapting choice future pathway as it unfolds, part global stocktake, if is key consideration.