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McGill University Department of Geography GEOG 205 Global Change: Past, Present and Future Directions and Questions for Assignment I (Prof. Chmura), Winter 2011 due date: Wednesday, March 9, at beginning of class, 1:00 P.M. or beforehand in the assignment drop box room 7th floor Burnside Hall, directly across from the elevator. (Grades will be reduced 10 points for each day late, starting at 1:00 P.M.) Please place your name on the top of every sheet you hand in, in case they become separated. Do not return these sheets of directions. The main objectives of this assignment are to learn about patterns of deglaciation in North America and associated environmental change, as well as past and future trends in sea level. It should reinforce lecture material on proglacial lakes and isostatic changes, concepts of relative sea level as a function of eustatic sea level and isostatic changes, and how North America has been affected by the advance and retreat of glaciers. A secondary objective of this assignment is to help you learn to obtain information from maps of different scales. Review the material provided in "Appendix 1” (part of this handout) and consult “Chapter 16 Small Islands”, from Working Group 2 which considered Impacts and adaptations to climate change as part of the Intergovernmental Panel on Climate Change’s fourth assessment. Complete reports of all working groups are available from the organization’s website (www.IPCC.ch), but you can easily access this particular chapter from the Assignment 1 folder (see Resources) on the course WebCT site. You should also review the lecture on sea level and its supporting material before starting your essays for questions 10 & 15. Answer all questions in the space provided, unless indicated otherwise. Completion of this assignment will require at least one, perhaps more visits to Hitschfeld Library (plan on an hour or two per visit). Bring a ruler and calculator. If you have never used a contour map you should review the section titled “contour lines” before proceeding with part II of the assignment. Don’t hesitate to ask the TA for help, as we have scheduled special consulting time in the Hitschfeld library specifically for this purpose. The TA consultation hours are posted in the library and on the calendar on the WebCT course site. It may be useful to discuss portions of this assignment with other students, but it is expected that preparation of written answers is to be an individual effort. With the exception of graph paper, the question and answer sheets will be available in the Assignment 1 folder on the course webct site – you must turn in your work on the answer sheet and use the graph paper provided. (No cover pages or special holders, please.) This handout includes: 1) five pages of background and questions, 2) Appendix 1 Explanatory notes published with paleogeography maps 3) Appendix 2 (text and graph of eustatic sea level change), and 4) Appendix 3 (text to help you read contour maps). Many questions must be answered by referring to the set of maps on display in Hitschfeld Library (5th floor, Burnside Hall):

Dyke, A. S. 2005. Late Quaternary vegetation history of northern North America based on pollen, macrofossil, and faunal remains..Géographie physique et Quaternaire 59( 2-3):211-262. selected maps also available with an interactive map viewer on the website of Natural Resources Canada. Dyke, A. S. and Prest, V.K. 1987: Paleogeography of northern North America, 18 000 - 5 000 years ago; Geological Survey of Canada, Map 1703A, scale 1:12 5000 000. Dyke, A. S. and Prest, V.K. 1987: Late Wisconsinan and Holocene Retreat of the Laurentide Ice Sheet; Geological Survey of Canada, Map 1702A, scale 1:5 000 000. Bier, J.A. 1995. Reference Map of Oceania, The Pacific Islands of Micronesia, Polynesia, and Melanesia. University of Hawaii Press. Survey and Mapping Branch. 1980. Truro, Nova Scotia, 11 E/6, edition 4. Department of Energy, Mines and Resources, Ottawa, Canada, scale 1:50,000. United States Army Corps of Engineers. 1960. Amsterdam, Netherlands, Series M 501, Sheet NN31-12, Edition 2-TDN. Scale 1:250,000.

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GAINING A SENSE OF PLACE AND SCALE.... 1. On the map included with your answer sheets, locate and label the following: the St. Lawrence River, the Mississippi River, MacKenzie River, the five Great Lakes (Superior, Huron, Erie, Ontario and Michigan), James Bay, Hudson Bay, and the cities of New York, Montreal, Toronto, Edmonton and Boston. ICE RETREAT give the age on the map (refer to maps with individual dates unless indicated otherwise) that indicates the earliest occurrence; do not interpolate 2. Over what period did the Laurentide Ice Sheet retreat from the areas listed on the answer sheet? Place

your answer in the space next to the place name? 3. Chmura's paleoenvironments lab is working with McGill Prof. Andre Costopoulos at an archaeological

site southeast of James Bay. This dig reveals that there were significant differences in food resources available to local people in the past. Today, Cree harvests are predominantly geese (which use tidal marshes along the Bay coast) and coastal fish. Surprisingly, bone of marine seal was found at an archaeological dig ~100 km inland from the present shoreline. What is the earliest point in the Holocene when people would be able to harvest marine seal on James Bay?

GLACIAL LAKES 4 Locate Glacial Lake Agassiz. Determine when it reached its greatest extent and roughly sketch its

location on the map included with your answer sheets. PALEOENVIRONMENTAL CHANGE As we work with finer scale-maps we are able to show more detail, for instance more variation in biomes. The paleovegetation maps produced by the Geological Survey of Canada subdivide these vegetation units in a manner that reflects the transitional zones that occur. They depict a region between boreal forest and tundra where trees grow sparsely in the tundra – called “forest tundra.” As conditions get colder the forest tundra grades into a “shrub tundra” and eventually tundra. There is also a zone called the “mixed forest” which is a transition from temperate deciduous to boreal forest. Note that immediately after ice retreated from the Montreal area it was covered by the Champlain Sea (see 10 k yr BP vegetation map). 5. At 10 k yr BP what vegetation zone was immediately adjacent to the a. north b. south? 6. At 9 k yr BP what vegetation zone was immediately adjacent to the a. north b. south? 7. When was the present mixed forest zone established in Montreal? SEA LEVEL GLACIERS AND EUSTATIC SEA LEVEL CHANGE The last major glaciation took place during the Late Wisconsinan, ending roughly 10,000 years ago. Based upon more than a century of field observations, it is now possible to reconstruct the northern hemisphere ice sheets. Reconstructions generally fall in two categories – minimum and maximum- according to overall ice coverage and thickness. The minimum reconstruction includes large ice sheets in North America, Greenland and Europe that were confined mainly to existing land areas. Smaller, thinner ice sheets/caps were located in several other areas: Iceland, the Alps, Svalbard, the Rocky Mountains, the Andes, etc. The Laurentide Ice Sheet in North America consisted of two domes with thicknesses exceeding 4 km. The minimum Scandinavian Ice Sheet had a single dome located over the northern Baltic with a thickness exceeding 3 km. It may have joined with a smaller ice sheet over the British Isles. Ice sheets in the maximum reconstruction were thicker and extended further. View the reconstruction of the retreat of the Laurentide ice sheet on the maps displayed in Hitschfeld Library.

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Below is one set of estimations for glacier volume during the Last Glacial Maximum.

estimate for Wisconsinan minimum maximum

Glacier/Ice Sheet times 1015 cubic metres North America 33.05 33.05 Greenland 0.80 1.20 Scandinavian, Barents, & Kara

5.54

7.22

Antarctic 5.62 8.42 All others 2.41 2.41

Totals 47.42 52.30

During the Quaternary, global sea level rose and fell in response to the volume of water stored on land in ice sheets and glaciers. Many attempts have been made to measure the size of past ice sheets and corresponding changes in eustatic sea level. The numerical results depend on assumptions about the area and thickness (that is, volumes) of ice sheets. Relative sea level change is affected by isostatic depression and rebound beneath both the ice sheets and the oceans, a topic you will address later in this assignment. 8. You will apply the estimates of past minimum and maximum ice sheet volumes to determine changes in eustatic sea level in the past. (Note that this method does not take into account any possible depression or rebound of coastlines, differences due to thermal expansion, or include correction for any change in surface area of the ocean due to higher or lower sea levels.) Procedure: Convert ice volumes to water volumes, and place the results in the appropriate cells of the table on your answer sheet. Water volume is about 0.9 times that of its corresponding ice volume, thus all ice volumes must be multiplied by 0.9. To calculate the equivalent sea level height divide each water volume by the area of ocean, 361 million square kilometres (we can disregard any change in ocean area) and transform this to the nearest metre. Write the sea level change (in metres!) in the appropriate cells of the table. RELATIVE SEA LEVEL 9. a Using the numerical data on the paleogeography maps (sheets 1, 2, 3) record the changes in paleosea level with respect to today’s sea level for the areas noted on the answer sheet, (There may not be a "sea level" for some early dates). b. On the graph provided plot the change in relative sea level vs. time for Portland, Maine (USA) and Cape Cod, Massachusetts (USA) using the data you have recorded in the table. Label each curve. On the same graph, plot an approximation of the eustatic sea level curve provided as part of Appendix 2. 10. Compare your two curves, which reflect changes in relative sea level, to the eustatic curve. For each curve give reasons (in the space provided on the answer sheet) why it’s shape and direction differ from the eustatic curve in terms of what was probably happening to the Earth’s surface in that region. For instance, do you see any indication of “isostatic rebound”?

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FUTURE SEA LEVEL We can estimate future increases in sea level using the same procedure applied to past ice sheet volumes. Find the table in your answer sheet that lists estimated volume of glaciers existing today. 11. Calculate the equivalent sea level rise in metres (to the nearest tenth of a metre) and write this in the blank cells of the table. 12. Under present conditions of greenhouse warming an important component of sea level rise is the thermal expansion of the oceans due to warming. Perform some rough, “back of the envelope” calculations of how much this will increase sea levels. In this exercise the change in area of the ocean can be considered negligible. Assume the upper 10% of the ocean (~379 m) is warmed by 3°C. We will also assume an average ocean water temperature of 10°C and average salinity of 35 ppt, thus use a coefficient of expansion of 1.5 x10-4 per degree C. a. Calculate the change in thickness of this upper ocean layer (= thermal expansion coefficient x change in

temperature x upper layer depth). The Intergovernmental Panel for Climate Change (IPCC) is an international panel of scientists who make predictions of future climate change, its causes, and the potential for increase in sea level. In their fourth assessment report released in 2007 (see summary for Policymakers at www.IPCC.ch) the IPCC estimated a maximum sea level increase of 59 cm by the year 2100. This estimate is based on the assumption that society continues its practices as today. (That is, there is no reduction in greenhouse gas emissions, continued forest clearance, etc.) b. Based upon your calculation, what proportion of the projected increase is due to thermal expansion? 13. Complete a table of elevations with respect to future sea levels following the resources described below below. Then subtract the IPCC estimated maximum rise in sea level for 2100 to determine future elevation with respect to sea level. New research produced since drafting of the IPCC report suggests that future sea levels were underestimated by the IPCC as it excluded rapid dynamical changes in the flow of Greenland and Antarctic ice, as well as more minor changes (see literary links in the sea level lecture notes). New estimates (e.g., by Vermeer and Rahmstorf 2009) suggest that eustatic sea level could increase as much as 1.9 m by 2100. Apply this new estimate for 2100 in the same manner to determine future elevation with respect to sea level. Oceania - Refer to the map of Oceania: The Pacific Islands of Micronesia, Polynesia and Melanesia". How will sea level rise affect the republics of Nauru and Kiribati? This map lists the highest elevation of many islands (written in metres, near the island name). On the table write the elevation of the islands listed. (The unit label is already indicated in the table title.) The Netherlands - Refer to the map titled “Amsterdam” which includes other cities such as Den Helder to the north of Amsterdam, Utrecht and Gouda to the south, and Apeldoorn to the east. This is a “contour map” with contour lines drawn at each increase of 20 metres elevation. Note there are no contours between Utrecht and Den Helder! However, “spot” elevations (in black) are given in a number of locations (see arrows we have placed on the map for examples – don’t confuse elevations with road distances that are also indicated, in brown). Many elevations are below sea level (thus are negative numbers). Write the lowest elevation you can find on the corresponding table in your answer sheet. Tides and Storm Surges at Truro, Nova Scotia – All coastal regions are subject to storm surges, but in areas with large tidal ranges the effect is considerably variable. The map entitled Truro, Nova Scotia shows Cobequid Bay (part of Minas Basin), which represents the southeastern arm of the head of the Bay of Fundy. The tidal range here averages 16 metres. This means that twice each day the waters of the Bay rise 8 metres above mean sea level and drop 8 metres below mean sea level. Note the

lines which indicate dikes. On this map all elevations are given in feet above mean sea level, so you will have to convert these values to metres. Contour intervals are every 50 feet. Spot elevations are written in some locations, indicated by a small arrow beside or below the number.

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What is the elevation of the shopping centre on the northwestern outskirts of Truro? Enter the elevation in the appropriate blank of the corresponding table in your answer sheet. Complete the initial entries for Truro by answering the following questions. How many metres above the level of high tide is this shopping centre? How many metres above a 1 metre storm surge at average high tide? Above a 2 metre storm surge? Vulnerability to Sea Level Rise –The IPCC provides the following caveat in their report: “Models used to date do not include uncertainties in climate-carbon cycle feedback nor do they include the full effects of changes in ice sheet flow, because a basis in published literature is lacking. The projections include a contribution due to increased ice flow from Greenland and Antarctica at the rates observed for 1993-2003, but these flow rates could increase or decrease in the future. For example, if this contribution were to grow linearly with global average temperature change, the upper ranges of sea level rise for SRES scenarios shown in Table SPM-2 would increase by 0.1 m to 0.2 m. Larger values cannot be excluded, but understanding of these effects is too limited to assess their likelihood or provide a best estimate or an upper bound for sea level rise.” Fill in the rest of the blanks of the table by calculating the relative elevation of all sites with respect to the future sea levels in 2100 predicted by the IPCC and the change that would occur if ice sheets melted entirely. Rising sea levels can threaten low-lying lands with flooding, cause erosion, damage to structures and salinization of groundwater. Of course, some areas will simply be submerged. All results mean loss of income, and possibly lives of those in the threatened area. Consideration of vulnerability to sea level rise must take into account, not just the elevation of a country, but its ability to deal with the problems – the latter comes down to economics. What will it cost for a country to protect itself against projected (the IPCC estimates) sea level rise? Protection costs (in US dollars) for selected countries and Nova Scotia are listed in the last table of your answer sheet. Determine how “affordable” this protection is by comparing it to each area's economy. 14. Go to “The World Factbook” published at the website of the USA CIA

(www.cia.gov/library/publications/the-world-factbook/index.html). Search by country and find the information needed to complete the table.

15. The IPCC states that “vulnerability to climate change refers to the propensity of human and ecological

systems to suffer harm and their ability to respond to stresses imposed as a result of climate change effects. The vulnerability of a society is influenced by its development path, physical exposures, the distribution of resources, prior stresses and social and governmental institutions.”

Which of the places in the table at #14 is the most vulnerable with respect to sea level rise? Which is the

least? There is no one “right” answer to these questions, and social scientists still debate them. What do you think? Briefly express your opinion and support it in a short essay, less than 200 words (Place the word count at the end of the essay.) Type this, place your last name and student number at the top and attach it to your answer sheet.

Appendix 2

Appendix 3