All things Equal
13 hours ago Andy May 72 Comments
By Andy May
In an interesting linkedin debate between Tinus Pulles and me, two subjects came up that are related to one another and too complicated for a comment. First is Tinus’ question, “Will more atmospheric CO2, all other variables being equal, lead to a higher surface temperature.”
The second question arose when I quoted the following from the IPCC AR6 report:
“As a result, non-condensing GHGs with much longer residence times serve as ‘control knobs’, regulating planetary temperature, with water vapour concentrations as a feedback effect (Lacis et al., 2010, 2013).” (IPCC, 2021, p. 179).
And this comment from AR5:
“Currently, water vapour has the largest greenhouse effect in the Earth’s atmosphere. However, other greenhouse gases, primarily CO2, are necessary to sustain the presence of water vapour in the atmosphere. … So greenhouse gases other than water vapour provide the temperature structure that sustains current levels of atmospheric water vapour. Therefore, although CO2 is the main anthropogenic control knob on climate, water vapour is a strong and fast feedback that amplifies any initial forcing by a typical factor between two and three. Water vapour is not a significant initial forcing, but is nevertheless a fundamental agent of climate change.” (IPCC, 2013, p. 667).
Oddly, Tinus doesn’t think the IPCC is serious about Lacis, et al.’s idea that CO2 is a control knob for surface temperature and he apparently disagrees with it. His excuse is that in the first quote “control knob” is in quotes and in the second is in a colored box, which identifies it as an answer to a “frequently asked question” or FAQ 8.1 (chapter 8, pp 666-667).
https://wattsupwiththat.com/2024/06/04/all-things-equal/
