EGU23-6667, updated on 25 Feb 2023
EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Potential role of methane and other non-CO2 trace gases in past warm climates

Peter Hopcroft1, Diane Segalla2, Gilles Ramstein3, and Thomas Pugh4
Peter Hopcroft et al.
  • 1School of Geography, Earth & Environmental Sciences, University of Birmingham, Birmingham, UK
  • 2University of Paris-Saclay, LSCE, Environment and Climate Sciences, Saint-Aubin, France
  • 3Laboratoire des Sciences du Climat et de l’Environnement, Institut Pierre Simon Laplace, Centre National de la Recherche Scientifique–Universite de Saint-Quentin en Yvelines, Universite Paris-Saclay, Gif-sur-Yvette, France
  • 4Dept of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden

Past warm climates allow the evaluation model predictions of the response of the Earth System to elevated greenhouse gas levels. However, Earth System model simulations routinely underestimate high-latitude warmth for past states, meaning that the forcings provided to models, the models themselves or the climate reconstructions are in error. We focus on the first of these and review the potential role of varying levels of atmospheric trace gases besides carbon dioxide (non-CO2 trace gases), which has been investigated in relatively few studies to date. Using a combination of terrestrial biogeochemistry models and simplified atmospheric chemistry scheme we make first-order estimates of the radiative forcing by non-CO2 trace gases for the mid-Pliocene and compare these with new results for the Miocene. We will discuss the main uncertainties involved and review potential avenues for future research.

How to cite: Hopcroft, P., Segalla, D., Ramstein, G., and Pugh, T.: Potential role of methane and other non-CO2 trace gases in past warm climates, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-6667,, 2023.