Earth’s cryosphere: much if not all of Canada’s hydrology is influenced by the cryosphere
Canada’s glaciers: about 200,000 km² if ice, ¾ of it the Arctic Archipelago
Comox Glacier: see the changes over a 3 year period
Devon Island: the ice cap meets the sea over a 15 km calving front
Peyto Glacier mass balance: the long term trend is clear even through the large annual variations
Global summary: most areas decline while Scandinavia grows due to increased precipitation
Peyto Glacier history: changes in size since 1840
Ice core story: the cores show more melt features now than at any time since the last ice age ended
Field work – the good: Columbia Icefield on a sunny day
Field work: – the bad: and the more common poor weather (digging out camp day after day)
Mike Demuth – “Cold Matters: Cryospheric Change and Related Hydro-ecological Functioning” by Tom Koleszar, 26 Sep 2019.
Mike is an Emeritus Research Scientist in Glaciology and Cold Region Environments who lives part-time in Lund. Mike’s talk introduced us to Earth’s cryosphere and then focussed on mountain glaciers. More can be learned about the cryosphere here.
We learned a great deal about how to measure glaciers and track changes to their mass balance over time – not a simple task! Direct field measurements shown included stake farms, digging pits, and drilling holes through the ice – in all kinds of weather! Remote sensing through photography, Lidar, and satellite measurements is also very valuable today.
The talk then turned to focus on the results – the dramatic changes taking place today in most of the world’s alpine glaciers. Warming conditions and changes to precipitation patterns can be seen very clearly in the ice measurements – one advantage of cryosphere research is that it is easy to eliminate weather noise for climate data. The changing ice mass then has pronounced hydrology effects downstream on resource industries, agriculture, wildlife, recreation, and domestic water supplies.
In closing, Mike paid homage to some of the original 19th century workers in glaciology, and showed some more great pictures of some nice days – and not so nice days – in the field.
Why is there an island in the middle of the Pacific Ocean? Plate tectonics and volcanoes. – B. Sherriff
Easter Island is actually formed by three volcanoes. Bacause of plate tectonics, these formed in “approximately the same place” over millions of years…making Easter Island quite different from the long, drawn-out string of volcanoes that make up the Hawaiian Islands. – B. Sherriff
Thor Hyerdahl was wrong – about a number of things! – B. Sherriff
The last “true-blood” Rapa Nui woman died in 1946…but the language and culture lives on, with a significant population inhabiting mainland Chile. – B. Sherriff
What’s the difference between a Maoi and a Ahu? The Ahu are the platforms that the statues (Maoi) stand upon. The mysterious Moai were powerful ancestors often chiefs placed on a platform (Ahu) to protect a village. – B. Sherriff
In 1774, the island was rediscovered during the second voyage of Captain James Cook. One of the expedition’s artists was William Hodges, who painteded this famous watercolor. He’s one of few who saw the Moai still standing.
Rana Raraku Quarry (where all the Moai were carved) has 397 Moai in various stages of carving…carving Moai was a business !!! – B. Sherriff
Contrary to popular belief, the Rapa Nui did not cut down all the trees and move the Moai along on rollers. Instead they carved them with a “keel” and “walked them along”…like moving a heavy appliance – B. Sherriff
Why did the Moai get toppled? War. – B. Sherriff
The native trees did get wiped out…primarily because of clearing for agriculture, wood used for cremations, and the introduction of rats. – B. Sherriff
The adoption of “Birdmen Culture” (1600-1867) ended tribal warfare and the local “military industrial complex”…and in turn that ended when Christianity arrived… – B. Sherriff
Something rarely seen…Barbara up at the crack of dawn! – B. Sherriff
Yes, the glaciers of Patagonia are impressive! – B. Sherriff
Barbara Sherriff “Moai and volcanoes of Easter Island…and Patagonian glaciers” by Andrew Bryant, 23 May 2019.
The Club’s very own Barbara Sherriff, well-known for her globetrotting adventures, recently returned from another epic voyage – this time to Easter Island and the glaciers of Patagonia!
Always the consumate educator, Barbara provided a hugely informative and highly amusing talk, deftly switching from tidbits about geology (did you know the Moai all wore “hats” of red volcanic scoria carved from a single quarry at Puna Pau?) to social commentary (why we could all benefit from adopting aspects of “Bird Man Culture“).
In turn, we learned about:
Why there’s an island in the middle of the Pacific Ocean
Where the Rapa Nui people came from
What happened to them
What the giant statues represent
The difference between a Moai and an Ahu
How the Moai were made
How they were moved
Why they were toppled
What happened to the native trees
Whew. And if that weren’t enough, we were then taken on a side-trip to the glaciers of Chile and Argentina, where we got to witness something truly amazing…Barbara up at sunrise…