The Phanerozoic sedimentary archives of the greenhouse condition of our planet provide valuable information on the warmer atmosphere-ocean systems unexperienced by Homo sapiens, but considered a potential for near future if the drawdown of GHG (green house gases) will fail to follow optimistic projections. One of these archives is the Devonian Horn River Group (HRG) of the Mackenzie River corridor. This talk explores the HRG from this angle, which for broader audience may be an unusual view on what is conventionally seen as the major TPS (total petroleum system) in the NWT jurisdiction. This work is a contribution to the Mackenzie Project of GEM Program. The targeted studies of the Devonian TPS were also conducted under GNES Program.