Reposted from NOT A LOT OF PEOPLE KNOW THAT
NOVEMBER 6, 2021
By Paul Homewood
Justin Rowlatt, brother of Insulate Britain loon Cordelia, has flown to Alaska now to complain about melting glaciers:
https://www.bbc.co.uk/news/av/world-us-canada-59186214
He visited the well-known Portage Glacier to make his level.
It’s a pity the ineffective Rowlatt didn’t do his homework first. It’s effectively established amongst glaciologists that glaciers in Alaska expanded massively throughout the Little Ice Age. Certainly, the stays of forests now being uncovered by receding glaciers, dated again to the Center Ages, present that glaciers then had been a lot much less intensive than now.
It’s also recognized that fashionable glacial retreat started within the 19thC, lengthy earlier than any supposed affect from AGW, which Rowlatt desires responsible.
I did an in depth evaluation of the Portage Glacier two years in the past, following Michael Portillo’s filming there of his sequence Nice Railroad Journeys. I gained’t copy it in full, however you’ll be able to see it here. The salient factors are under.
To recap, Michael Portillo’s railway journeys are based mostly across the Appleton’s journey guides from the 19thC. There was even one for Alaska, which included this gem:
“Outdated residents insist that the local weather is altering. That the summers are hotter and drier. The fast retreat of all of the glaciers throughout even 20 years is obtainable as one other proof.”
The information was revealed in 1899, so that is good proof that glacier retreat started lengthy earlier than even then.
The US Geological Survey confirms that the Portage Glacier itself has been receding since at the least 1914, and that the quickest retreat occurred between 1939 and 1950:
In the course of the late 1800s and early 1900s, Portage Glacier terminated on land on the western finish of Portage Lake, filling Portage Lake with ice (Photograph Plate 1914). For the reason that early 1900s, the glacier has receded, leaving Portage Lake within the scoured basin. The preliminary retreat of the glacier coincides with recognized local weather warming related to the tip of the Little Ice Age (circa mid-Nineteenth century). Because the glacier receded, its land-based terminus retreated into proglacial Portage Lake and adjusted from its comparatively secure land-based atmosphere to an unstable calving atmosphere. Essentially the most fast recession of some 140 to 160 meters per 12 months occurred between 1939 (Photograph Plate, 1939) and 1950, when water depth on the terminus was at its most—roughly 200 meters. Recession continued by means of the Seventies and Nineteen Eighties (Photograph Plate, 1972, 1984) till by late 1999, Portage Glacier had receded virtually 5 kilometers, to a extra secure place on the japanese finish of Portage Lake (Photograph Plate, 1999). The retreat was pushed primarily by calving of unstable ice on the glacier terminus into Portage Lake. Ice loss ensuing from elevated melting of the glacier floor throughout the previous century-long normal warming pattern contributed to glacier retreat, however to a lesser extent. At present, the terminus of Portage Glacier stays near its 1999 location.
As I wrote on the time:
Many scientists have intently measured and studied glaciers all through Alaska, and the conclusions have at all times been the identical. Alaskan glaciers, which grew enormously throughout the Little Ice Age, started fast retreat throughout the 19thC.
However it’s fascinating that this was all frequent data to a author of a vacationer guidebook revealed in 1899.
That author evidently knew extra about Alaskan glaciers than Justin Rowlatt does now!
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