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Geographical Association Annual Conference 2006 “Lecture Plus”

Geographical Association Annual Conference 2006 “Lecture Plus”. Glaciers and Glacial Landscapes Dr Peter G Knight, Keele University www.esci.keele.ac.uk p.g.knight@esci.keele.ac.uk.

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Geographical Association Annual Conference 2006 “Lecture Plus”

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  1. Geographical Association Annual Conference 2006 “Lecture Plus” Glaciers and Glacial Landscapes Dr Peter G Knight, Keele University www.esci.keele.ac.ukp.g.knight@esci.keele.ac.uk School texts have not kept pace with glacier science over the last 30 years. My book in the GA series “Changing Geography” was a response to this problem. • Problems & Opportunities • Examples • Ways Forward • Discussion

  2. Geography is a fantastic subject! It’s a wonderful world… Geography is all about exploring it.

  3. You don’t have to explore very long to realise that: Everything is connected in a complex system Glaciers, climate, sea-level, tectonics, geomorphology, ocean currents, etc…

  4. 1. glaciers 2. coasts 3. rivers So, while you could design a whole course doing topics one at a time… 4. mountains, 5. deserts, etc., etc…

  5. …you don’t need to because they are all connected. eg: the waterfall and the glacier move in response to the same forces. There’s a bigger picture to be interested in.

  6. We’re trying to understand the rules that control how all of these things work and how they fit together as part of a global system In understanding the landscapes around us, we recognise connections between topics across different scales…

  7. Glaciers are very good for illustrating connections between parts of the global system at different scales… eg in the hydrological cycle • OCR Geography A-level Spec (2007): Module 2680 The Physical Environment • “As an introduction to this module the global hydrological cycle should be studied as a generalised, closed system.” 77% of Earth’s fresh water is in ice sheets In many places, glaciers provide the only dry-season water supply

  8. Glacier science is exciting because it’s a subject in which there has been progress and discovery. Teaching glaciers is problematic because different textbooks have kept up with the science to differing degrees, meaning that different books say different things, and few of them are up to date.

  9. Fundamental problems in teaching Physical Geography: • keeping up with new discoveries • choosing reliable teaching resources • knowing what to tell students • Especially when popular textbooks and websites such as the BBC are perpetuating out-of-date or incorrect information…

  10. For example: Drumlins… AQA Examiners’ Report (GCE Geography A, 2005) “…a significant minority of candidates appeared to have no relevant knowledge and understanding concerning drumlins… Some simply stated that the glaciers somehow became tired, unable to carry on in lowland areas and dumped their load.”

  11. From the textbook: An explanation of DRUMLINS from the A-level textbook previously used by most of my incoming 1st-year Univ students (a book described by one teacher’s web site as “as good as it gets”): “The most widely accepted view is that they were formed when the ice became overloaded with material and so the competence of the glacier was reduced. The reduced competence may have been due to the melting of the glacier or to changes in velocity…”

  12. From the BBC: Lodgement till: This is sometimes referred to as Ground Moraine. It is theMaterial that is deposited under ice while the ice is moving. This action is almost like smearing and occurs when the weight of material becomes too great to carry on by the glacier. Features created by this deposition include Drumlins http://www.bbc.co.uk/schools/16/sosteacher/geography/49085.shtml

  13. From revision-notes.co.uk: • Ice Movement • Ice may move through one of these three processes: • Plastic Flowage: Ice has plastic qualities and may flow en-masse like a viscous liquid • Basal Slip: The process through which ice slips and slides over the underlying rock. • Internal Shearing: Movement similar to rock faulting involving differential sliding along planes. • The speed of ice movement depends on the gradient of the slope and the thickness of the ice. http://www.revision-notes.co.uk/revision/187.html

  14. From revision-notes.co.uk: • Ice Erosion • This involves three processes: • Plucking: Parts of the underlying rock are frozen into the base of the ice and pulled away. • Glacial Abrasion: The grinding process where stones frozen in the ice scrape and scratch against the underlying rock. • Sapping: The breaking of rocks by the alternate freezing and thawing of the ice at the bottom or sides of the mass. http://www.revision-notes.co.uk/revision/187.html

  15. This is both a problem and an opportunity • New research: • puts “errors” into old textbooks • but • helps to make the subject more exciting to learn and to teach • We can use glaciers to talk to students about science being dynamic, relevant, cutting edge, topical, interdisciplinary. We can use glaciers to illustrate complex linked systems, Global and local scale interactions, etc…

  16. Climate-independent glacier fluctuations Why does the ice reach exactly this point and no further? EXAMPLE BBC: “Glacier retreat is a sure sign of global warming.”

  17. Climate-independent glacier fluctuations Real answer 1. Changing basal friction: 1. Accumulation and thickening 1 2. Increased basal deformation, acceleration, advance, thinning… EXAMPLE 2 3. Basal cooling, less basal deformation, slower flow, thickening, retreat. 3

  18. Climate-independent glacier fluctuations Real answer 2. Floating glacier margins: EXAMPLE W.Greenland NB: Ice-shelf “collapse” W. Greenland

  19. Climate-independent glacier fluctuations Real answer 3. Ice-divide migration EXAMPLE Pictures provided by Andrew Dugmore

  20. Climate-independent glacier fluctuations Real answer 4. Surface debris inhibiting ablation EXAMPLE Myrdalsjokull, Iceland

  21. The world is even more interesting than the text books tell us! The basal ice layer Ice streams Deformable beds Surging glaciers Megafloods and Jokulhlaups Unexplained UK landforms Glacier hazards from global warming Glaciers flowing up-hill Glaciers controlling climate etc…

  22. “I have spent the last 20 years or so pondering enormous floods from beneath the Pleistocene Ice Sheets. I think these floods may have formed drumlins, one of the most enigmatic landforms on Earth. • Drumlins: more interesting than the books tell us… • Hypothesis 1: Deposition by ice • Hypothesis 2: Erosion by subglacial megafloods • Hypothesis 3: Deformation of subglacial debris EXAMPLE Prof. John Shaw, University of Alberta. http://www.engineering.ualberta.ca/civil/shaw.cfm “The strongly polarized debate about the origin of drumlins exemplifies the problem when speculation is relatively unconstrained by definitive evidence…” Prof. Geoffrey Boulton, University of EdinburghIn Knight, P.G. (2006) Glacier Science and Environmental Change (Blackwell).

  23. Glacier motion: we know more now than we did when they wrote the old books! • From revision-notes.co.uk: • Plastic flowage • Basal slip • Internal shearing • The real story: • Internal deformation of the ice • Sliding of the ice across its substrate • Deformation of the substrate beneath the ice EXAMPLE • “Until the 1970s, sliding and internal deformation were the only mechanisms that scientists recognised. The idea that deforming beds contribute to glacier motion has been one of the most important ideas in recent decades. Substrate deformation is now a well-established part of our understanding.”

  24. Glacier motion: examples of different glaciers ice ice substrate Glacier sliding creep deformation Meserve - 100% - Variegated (winter) - 100% - Variegated (summer) 30% 70% - Variegated (surge) 95% 5% - Urumqui 1 3% 37% 60% Breidamerkurjokull 12% - 88% EXAMPLE

  25. Ways forward… • bridging texts • eg The GA’s “Changing Geography” series • school/university interaction • eg visits/workshops/correspondence • teacher-researcher co-authorship • eg web-sites, text books, etc

  26. Conclusions 1 Glaciers provide valuable theme linking local/global, present/past, human/physical. We should include them more in our curricula. The rapidly moving research frontier makes it exciting for students to learn about glaciers and to see their relevance to real-world issues such as environmental change. However, it makes it hard for textbooks and teachers to keep up.

  27. Conclusions 2 There are opportunities for resources that “bridge the gap” between A-level teaching and new discoveries. There are opportunities for collaboration between Schools and Universities: why don’t teachers from schools and universities get together more? Physical Geographers at Keele University would be glad to offer whatever help we can.

  28. Thanks for listening. Please get in touch! Dr Peter G Knight, Keele University www.esci.keele.ac.uk/physicalgeography p.g.knight@esci.keele.ac.uk A copy of this lecture, and related materials, will be placed on the GA website and on the physicalgeography.org.uk website at http://www.physicalgeography.org.uk

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