This is a silly discussion, but, briefly, try to look at the situation from the inside point of view. Carey is a professor at a university, he gets grants from NSF, he publishes books and papers in peer-reviewed journals. A "scientist" is a high-status label and refusing to call himself a scientist would banish him to the bottom of the totem pole in his social circles.
You probably think of science as "hard sciences". But there are also soft sciences, aka social sciences and I believe historians, sociologists, etc. would not take kindly to being told that what they do is not science. Their internal perspective is that they engage in science, not in diddling with pot shards in their navels.
Look at yourself :-) and avoid the typical mind fallacy.
Here's an interview with Carey. His initial description of himself is as a "historian of science and environmental historian", but later on he does refer to "social scientists like myself".
So, you were right and I was wrong (in, at least, a way I predicted I might be): he does, at least in some contexts, call himself a scientist.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
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