ES322 Glaciers and Climate Change Lab Case Study Grinnell Glacier Montana Introduction Glaciers are ephemeral climate related features that dramatically imprint the shape of the landscape over time This investigation examines the historical changes to Grinnell Glacier in Glacier National Park Montana Figure 1 Grinnell Glacier is one of the largest remaining glaciers in the park even though it is less than a square mile in area Historical Field Mapping First measurements of glaciers in Glacier National Park were conducted as part of topographic field mapping in 1900 From the early 1900 s to the 1960 s several scientists working with the National Park Service created a photographic archive of glaciers with re surveying on a regular basis throughout the 1900 s See the attached map Figure 2 showing the position of the glacial front historically during the early and mid 1900 s The map is from U S Geological Survey Professional Paper 1180 Grinnell and Sperry Glaciers Glacier National Park Montana a Record of Vanishing Ice published by the USGS in 1980 Several copies of a larger format version of this map are available in the lab for use but do not remove from room so everyone can share Part I Initial Observations and Predictions Consider the attached aerial photo Figure 3 of Grinnell Glacier showing the areas it covered in 1850 1937 1968 and 1993 Note that the map in Figure 2 shows glacial front positions for 1887 1937 1946 1960 and 1968 Has this glacier been advancing or retreating over time What factors control glacial advance and retreat How does the photo record relate to current theories about global climate change and human impacts to the global carbon budget Based on the photo evidence in approximately what year do you think that Grinnell Glacier will be completely transformed How did you come up with your estimate Part II Data Collection and Analysis Divide into 6 teams of 2 each team will select one of the following years 1887 1937 1946 1960 1968 or 1993 Using a copy of Figure 2 highlight and outline the extent of Grinnell Glacier for your year Then carefully cut out your glacier outline or trace it directly onto the 10 x 10 graph paper available on the class web site Then count the number of squares of graph paper contained within your traced outline Count every full square and any square that is more than halfway in your traced outline The total should be very close to the surface area of Grinnell Glacier that year in squares Determine the following SHOW ALL OF YOUR MATH WORK 1 Year of Glacial Front Used in Analysis Total No of Graph Squares Map Scale of Figure 2 1 inch meters on ground 1 square inch on graph square meters on the ground No of Graph Squares per square inch No of square meters per graph square Total Scaled Area of Active Glacier for your year in square meters Total scaled area of active glacier for your year in square kilometers Distance of glacial front in your year from upper most elevation of ice m Distance of glacial front in your year from upper most elevation of ice km Sharing data with other teams complete the table below Grinnell Glacier Summary Data Year Area of Active Glacier sq meters Area of Active Glacier sq km Distance of front from origin km 1887 1937 1946 1960 1968 1993 Using Excel another favorite software package or hand graphing techniques create the following graphs Active Glacier Area Y axis vs Year X axis Distance of Front Y axis vs Year X axis Print your results and attach Part V Interpretation Write a 1 2 page summary of the results of your observation and analysis In your analysis provide a linkage between your observations at Grinnell glacier and the historic global atmospheric temperature data depicted in the graph on Figure 4 Place your summary in the context of global climate change possible causes for historic glacial retreat and Grinnell and long term implications from glacial analysis at Glacier National Park MT 2 Scale 1 15062 Figure 2 Map showing historic locations of front of Grinnell Glacier Montana Approx Scale 1 16342 Figure 3 Historical photo base and locations of Grinnell Glacier lobe margins 1850 1993 Figure 4 Historical average atmospheric temperature on continental land masses 1850 2000 Free Plain Graph Paper from http incompetech com graphpaper plain Free Plain Graph Paper from http incompetech com graphpaper plain