In a critique (or possibly a rant) against modern climate science, Swiss geologist Christian Schlüchter makes a very specific claim that Alpine glaciers were essentially non-existent (or very much smaller than they are today) in Roman times. From a blog translating his original interview:
...the glaciers during the Roman times were at least 300 to 500 meters higher than today. “The mean temperature was one and half degree Celsius above that of 2005. The current development is nothing new in terms of the earth’s history.”
Early in the interview Schlüchter reminds us that during Roman times in the Alps “the forest line was much higher than it is today; there were hardly any glaciers. Nowhere in the detailed travel accounts from Roman times are glaciers mentioned.”
There are a number of contentious criticisms of climate science and some highly debatable claims about causality (is it all about the sun?). And I can't think of an easy way to verify Roman temperatures that wouldn't be controversial.
But the claim that Alpine glaciers were much smaller is surely a matter of history and should be verifiable from historical sources. So, is his claim that they were much smaller in Roman times correct?