These are scientists who probably have some idea of how to measure variance. You're some rando on the internet shooting from the hip. ¯\_(ツ)_/¯
Here's the paper, go wild: https://www.jstor.org/stable/43601643
This repurposed quote from the raiders of the lost ark might also work:
"I assure you ... We have top men working on it!"
"Who?"
"Top. Men."
I just get triggered at low-effort skepticism. Tomsaga read the word "stable" and assumed it meant "absolutely stable", and didn't ask himself "huh, I wonder if the pop-sci article is masking a more complicated concept with an easy-to-digest concept".
To get more into the climate stability: What they're doing is measuring the difference in temperature and precipitation between the Last Glacial Max and the Last Interglacial. And the maps don't even have `0` in their range, they have a small number but not zero. So yes, climate wasn't stable, but they were able to measure "how stable" it was. (Pages 1-3 in the paper.)
In contrast, when it comes down to John Q. Internet vs a scientist with relevant expertise, I think it's a reasonable heuristic to think the scientist is more likely to be correct.
IMO the downvotes were more related to the delivery than the content.
If the discussion was "who is more likely to be right", well, that's a different matter and I'd agree with credentials. But that's not an interesting discussion really.