| The blog post you cited seemed pretty dodgy to me, so I went ahead and looked closely at the work they base many of their conclusions on, a PhD thesis from 2004 by Kouwenberg [0]. Specifically the data in Fig. 5.4 (p. 57) is what they base much of their argument on. Kouwenberg herself however doesn't believe the crazy 300-700 AD CO2 excursion to around 400 ppm and spends a lot of time looking at alternative explanations, finally concluding on p. 65: """ The extremely low number of stomata per mm needle length in the Tsuga heterophylla record at Jay Bath between 300 and 700 AD does not appear to result from extremely high
atmospheric CO2 levels at the time, but coincides with the establishment of the species during a period of major disturbance at the site. The open, exposed setting after this disturbance probably provided highly stressed growth conditions for pioneering, early-successional T. heterophylla trees. """ Of that, there is of course no mention in the blog post you cited. Importantly, of course, none of this is really that relevant to the discussion of anthropogenic global warming, since we know that we are putting CO2 into the atmosphere, and that CO2 in the atmosphere traps heat. I'm really starting to see a pattern here, where facts that contain some grain of truth are used out of context to sow doubt, and everything just evaporates as soon as you look more closely (and then the next tangentially relevant fact is brought up)... It's probably quite effective - I mean, who is going to read that blog post you linked and then do what I just did and actually dig into the sources? I did that because I took the "advice" I got in this comment section to heart and wanted to give my "opponents" the benefit of the doubt. [0] PDF available at https://dspace.library.uu.nl/bitstream/handle/1874/243/full.... |