The protocol for the intercomparison is now published and available as:
C. Goldblatt, L. Kavanagh, and M. Dewey, The Palaeoclimate and Terrestrial Exoplanet Radiative Transfer Model Intercomparison Project (PALAEOTRIP): experimental design and protocols, Geosci. Model Dev., 10, 3931–3940, 2017,

Peer review is now closed. Comments made during the peer review may be seen at the doi above.


  • We compare radiative transfer codes run offline from climate models on fixed profiles. This isolates the fidelity of the radiation code from other aspects of climate models; this is the established methodology used for IPPC class models for some decades (see Collins et al., 2006, for general discussion). 
  • We have described 16 model experiments. 
  • These include variation of CO2 up to 0.1 bar, CH4 and N2O up to 0.01 bar, variation in surface pressure, inclusion/exclusion of ozone and variation of high and low cloud properties. 

Experiments should be run over winter 2017/2018, and will then be compiled by the PALAEOTRIP team. Please let us know by email if you will participate.  The expectation is that all contributors will be included in the final paper.