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You might need to rethink "glacial pace"

06 May 2020 | Science Notes

A set of recent studies surveyed by Kenneth Richard at No Tricks Zone reports on changes in glacier lengths in Asia. And make frequent use of a word you wouldn’t normally associate with glaciers, namely “surging”. And another: “advancing”. But many of them are doing the latter, in some cases by more than 1 kilometer per year. It doesn’t mean they’re going to outrun you and bury you. But taken together the studies show that glaciers are subject to long, natural cycles of advance and retreat, with little connection to regional temperatures, that can include what passes with gigantic frozen objects for dramatic moves over short times. Even the Alaskan glaciers near our “1919 or 2019?” contest town of Atlin BC are full of surprises.

Richard points to a 2014 study which used old maps and satellite data to track terminus points over time for 50 Alaskan tidewater glaciers, a term meaning ones that end in the ocean. Twenty-four of the glaciers on balance retreated. But 11 advanced.

The glaciers of Glacier Bay, the photogenic ones you will see on an Alaskan cruise if they ever start running again, have retreated over 100 km since the end of the Little Ice Age. And they continue to do so although some glaciers in the region are now advancing. Looking at the 36 glaciers that remained near tidewater throughout the whole time period of the study, the authors concluded that “The mean number of glaciers per year that underwent significant advance was less than the mean number of glaciers per year that underwent significant retreat (7.0±4.1 glaciers/year versus 8.2±3.7 glaciers/year), but no clear trends are present in either data set.”

Meanwhile in the mountainous regions of Asia, satellites are detecting rapid growth of glaciers, as much as a kilometer per year. This is the region of which the IPCC famously said the ice would be all gone by 2035. Nature, however, seems to have had other plans.

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