Presentation on theme: "Geographical Association Annual Conference 2006 Lecture Plus Glaciers and Glacial Landscapes Dr Peter G Knight, Keele University"— Presentation transcript:
Geographical Association Annual Conference 2006 Lecture Plus Glaciers and Glacial Landscapes Dr Peter G Knight, Keele University 1.Problems & Opportunities 2.Examples 3.Ways Forward 4.Discussion 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.
Geography is a fantastic subject! Its a wonderful world… Geography is all about exploring it.
You dont have to explore very long to realise that: Everything is connected in a complex system Glaciers, climate, sea- level, tectonics, geomorphology, ocean currents, etc…
1. glaciers 2. coasts 4. mountains, 5. deserts, etc., etc… 3. rivers So, while you could design a whole course doing topics one at a time…
…you dont need to because they are all connected. Theres a bigger picture to be interested in. eg: the waterfall and the glacier move in response to the same forces.
In understanding the landscapes around us, we recognise connections between topics across different scales… Were trying to understand the rules that control how all of these things work and how they fit together as part of a global system
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. In many places, glaciers provide the only dry- season water supply 77% of Earths fresh water is in ice sheets
Glacier science is exciting because its 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.
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resources knowing what to tell students Especially when popular textbooks and websites such as the BBC are perpetuating out-of-date or incorrect information… Fundamental problems in teaching Physical Geography:
…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. AQA Examiners Report (GCE Geography A, 2005) For example: Drumlins…
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… An explanation of DRUMLINS from the A-level textbook previously used by most of my incoming 1 st -year Univ students (a book described by one teachers web site as as good as it gets): From the textbook:
Lodgement till: This is sometimes referred to as Ground Moraine. It is the Material 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 From the BBC:
Ice Movement Ice may move through one of these three processes: 1.Plastic Flowage: Ice has plastic qualities and may flow en-masse like a viscous liquid 2.Basal Slip: The process through which ice slips and slides over the underlying rock. 3.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. From revision-notes.co.uk:
Ice Erosion This involves three processes: 1.Plucking: Parts of the underlying rock are frozen into the base of the ice and pulled away. 2.Glacial Abrasion: The grinding process where stones frozen in the ice scrape and scratch against the underlying rock. 3.Sapping: The breaking of rocks by the alternate freezing and thawing of the ice at the bottom or sides of the mass. From revision-notes.co.uk:
New research: puts errors into old textbooks but helps to make the subject more exciting to learn and to teach This is both a problem and an opportunity 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…
Climate-independent glacier fluctuations Why does the ice reach exactly this point and no further? BBC: Glacier retreat is a sure sign of global warming. EXAMPLE
Real answer 1. Changing basal friction: Accumulation and thickening 2. Increased basal deformation, acceleration, advance, thinning… 3. Basal cooling, less basal deformation, slower flow, thickening, retreat. EXAMPLE Climate-independent glacier fluctuations
W. Greenland Real answer 2. Floating glacier margins: NB: Ice-shelf collapse EXAMPLE Climate-independent glacier fluctuations
Pictures provided by Andrew Dugmore Real answer 3. Ice-divide migration EXAMPLE Climate-independent glacier fluctuations
Myrdalsjokull, Iceland Real answer 4. Surface debris inhibiting ablation EXAMPLE Climate-independent glacier fluctuations
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…
EXAMPLE 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 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. Prof. John Shaw, University of Alberta. 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 Edinburgh In Knight, P.G. (2006) Glacier Science and Environmental Change (Blackwell).
EXAMPLE Glacier motion: we know more now than we did when they wrote the old books! From revision-notes.co.uk: 1. Plastic flowage 2. Basal slip 3. Internal shearing The real story: 1.Internal deformation of the ice 2.Sliding of the ice across its substrate 3.Deformation of the substrate beneath the ice 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.
bridging texts eg The GAs Changing Geography series school/university interaction eg visits/workshops/correspondence teacher-researcher co-authorship eg web-sites, text books, etc Ways forward…
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. Conclusions 1
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 dont teachers from schools and universities get together more? Physical Geographers at Keele University would be glad to offer whatever help we can. Conclusions 2
Thanks for listening. Please get in touch! Dr Peter G Knight, Keele University A copy of this lecture, and related materials, will be placed on the GA website and on the physicalgeography.org.uk website at