alt Hacker NewsEarly IPCC reports, all the way up to AR5 basically threw their hands up when it came to permafrost emissions. They admitted we didn't have the necessary data yet and for the most part didn't account for it at all in their models
Check out the 1.5C special report. Go to section 2.2.1.2, last paragraph says
> The reduced complexity climate models employed in this assessment do not take into account permafrost or non-CO2 Earth system feedbacks, although the MAGICC model has a permafrost module that can be enabled. Taking the current climate and Earth system feedbacks understanding together, there is a possibility that these models would underestimate the longer-term future temperature response to stringent emission pathways
https://www.ipcc.ch/sr15/chapter/chapter-2/#:~:text=Geophysi...
The claim being discussed is not that they didn’t account for it, but that they didn’t attempt to account for it. Reading that text, I think they did, but chose not to include it (I guess because they didn’t need to to make their point and, by not including it, avoided opponents from arguing about the validity of the result based on uncertainties in those models)