EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

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

Katsumasa Tanaka1,2, Olivier Boucher3, Philippe Ciais1, Daniel Johansson4, and Johannes Morfeldt4
Katsumasa Tanaka et al.
  • 1Laboratoire des Sciences du Climat et de l’Environnement (LSCE), France (
  • 2Center for Global Environmental Research, National Institute for Environmental Studies (NIES), Tsukuba, Japan
  • 3Institut Pierre-Simon Laplace (IPSL), Centre national de la recherche scientifique (CNRS)/Sorbonne Université, Paris, France
  • 4Division of Physical Resource Theory, Department of Energy and Environment, Chalmers University of Technology, Gothenburg, Sweden

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

How to cite: Tanaka, K., Boucher, O., Ciais, P., Johansson, D., and Morfeldt, J.: Cost-effective implementation of the Paris Agreement using flexible greenhouse gas metrics, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-13088,, 2021.


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