And I wanted to add that a key factor for both angstrom and koch low - balling the importance of C02 concentration was not just that they didn't fully envision conditions where energy radiates away, but that they weren't modeling positive water vapor feedback (the magnitude of which but not the existence is still being hashed out). (realclimate.org)
Semantic issues aside, it's probably reasonable to view the assessment of climate sensitivity, as typically done, to entail a Planck («no feedback») response, in combination with feedbacks that include positive water vapor, ice - albedo, and probably cloud feedbacks, and a negative lapse rate feedback. (judithcurry.com)
WebHubTelescope: Positive water vapor feedback is known to contribute largely to the +33 C warming that prevents the earth from a 255K average temperature. (realclimate.org)