I ask dumb questions to tease out useful responses all the time, I don't think you're wrong in the general case, and an exhortation not to rush to judgement can only be good. But these guys have been at it at least twenty years. Every time they pop up with "what about the Mediaeval Warm Period/Little Ice Age/Roman Climatic Optimum?" someone explains that they're comparing local phenomena with a global phenomenon and they go quiet until the next time. There has to come a point where you are forced to assume bad faith.
I see Little Ice Age I assume bad faith and as much as possible politely reply to point out the irrelevance - not so much as to give them a response but to reply for the sake of young minds wandering by who might wonder about that sink hole.
I'd encourage all the genuinely curious to ponder all the angles, is it
* sun fluctuating,
* heat from below,
* can a gas in parts per million (PPM) really insulate enough to make a difference,
* biased data from urban heat islands,
* .. etc, etc, etc.
and for them to realise that all these things have been given honest consideration and found wanting .. decades ago in most cases.
I wasn't aware of the Little Ice Age being much of a denier talking point. It actually does seem fairly relevant to this story since these sponges lived through that time period. But I'm mostly just looking at the XKCD temperature timeline https://xkcd.com/1732/
It waxes and wanes I'm sure, but I've seen far too much raising of the Medieval Warm Period and the The Little Ice Age as "Aha, Gotcha!"'s over the past three decades to push it down the list of denier "but what abouts".
They're valid subjects in their own right, to be sure, but rarely raised in public forums for the interesting details in context, mostly for the "<something> <something> AGW must be wrong! ('cause climate has changed before fossil fuel usage!)"
The actual variation was small in comparison to what we are seeing now and the effect more localised than truly global - it tends to be lobbed in as a hand grenade along with "what about higher C02 levels many hundreds of thousands of years ago".
"Ice Age" itself is another awful phrase for generating confusion - there are multiple meanings and usages, for some professionals we are still in an Ice Age as we still have glaciers (free, not polar, ice) and this Ice Age experiences advances and retreats of large glaciers .. sometimes almost to the equator, othertimes back to the mountaintops. For most people "Ice Age" is when ice covers the UK and when it doesn't it's not.
Back to these sponges:
The surface waters above these sponges absolutely saw a small decrease in mean tempretures during the Little Ice Age.
I freely admit I haven't read enough here nor dug into the details to find out whether these sponges that lived deeper than surface waters saw a small decrease in mean tempreture at that time or not.
I didn’t read the paper but did read the article and one of the cool aspects of it was that they did go back in the timeline to find known historical temperature anomalies after calibrating the sponges against a modern period with good temperature measurements, so I would assume so.
I just wonder if this actually does change the “baseline” Earth temperature as the article implies rather than just adds a bit more detail to known historical temperatures.
As far as the temperature variation thing and deniers, I’ve always thought Munroe did an excellent job with the visualization I linked above in showing why the current change is so unprecedented when compared with previous ones.
