by P. Homewood, Nov 10, 2021 in NotaLotofPeopleKnowThat
A friend recently suggested that “melting glaciers” must surely prove “global warming is true”.
It is a common belief. After all, glaciers are a visible phenomenon and it all sounds logical.
As you know, I have written extensively about glaciers, (see the “glaciers” tab on the sidebar). But it is worth posting this potted history of them:
The modern day retreat of glaciers is part of a much longer natural cycle. Indeed, we find evidence of that cycle going back long before the Middle Ages.
Lamb, for instance, claims that glaciers in the Alps and Norway were advancing between 800 and 400BC, reaching an extent almost as great as during the Little Ice Age. They advanced again around AD600 to a similar position as before.
In between times, of course, the same glaciers also retreated, both during the Roman Warm Period and the Medieval Warming Period.
Whether man-made warming has played any part in modern glacial retreat, we know that:
- Most of the retreat since the 18thC occurred before any possible impact from humans.
- Glaciers were smaller than now in the Middle Ages
- There is nothing unprecedented or alarming about the current state of the world’s glaciers
All of this is common knowledge amongst glaciologists. But for some reason the world of climate science does not want the public to know.