Antarctica's Pine Island Glacier (PIG) is large and rapidly changing and flowing into the ocean as a floating ice shelf (above and Figure 1, p. 58). The PIG lies on the edge of the warming Antarctic Peninsula, the handle-shaped section of Antarctica (Figure 2, p. 58). The PIG drains ice from the West Antarctic ice sheet into the ocean--moving more ice than any other glacier in Antarctica. From 1996 to 2006, the PIG accelerated at a rate of 34% (Rignot et al. 2008) and is currently moving ice at speeds of up to 3.5 km/year (9.6 m/day) (Scott 2008; Bindschadler 2009). This accelerating transfer of ice from land to ocean is measured in the drop in ice elevation detected by satellites--one of three sets of evidence scientists use to assess the impact of warming on the ice sheets (others include measuring the acceleration of ice to the ocean and overall loss of ice mass).
A data visualization of the warming Antarctic with temperature changes per decade shown in degrees Celsius. In the image, red represents areas where temperatures have increased the most over the last 50 years. Most of West Antarctica shows as red.
NASA/GSFC SCIENTIFIC VISUALIZATION STUDIO (ANNOTATED BY AUTHOR).
Illustrating this process for students, the "Is the PIG a 'Climate Canary'?" activity described in this article links changing Antarctic ice directly with atmospheric and oceanic processes. The important role of these processes in warming the polar regions is an emerging area of scientific study; this activity allows students to study these processes and their effects in a meaningful way.
This activity teaches effectively about Earth's climate system because it places evidence directly into students' hands; students then connect this data to processes occurring in the wider Earth system and the mechanisms triggering change. Learning directly from data is powerful. When students see the connection between the data and the corresponding Earth processes, they experience an intrinsic thrill that cements their learning (Kastens and Turrin 2010).
The data for this activity are collected from four of the six years that NASA's Ice, Land, and Cloud Elevation Satellite (ICESat) was in orbit. With each repeat orbit, ICESat's laser measured the ice surface and collected ice-elevation data with an accuracy of within 14 cm (Shuman et al. 2006). Satellites monitoring Earth systems allow scientists--and now students--to measure changes in ice surface elevation through time (dh/dt) along satellite lines.
The "Is the PIG a 'Climate Canary'?" activity takes place in two 40-minute class periods. The first day's activities are described below; the second day is devoted to hands-on lab experiments, described later. (Full instructions for teachers and more about the science behind the activity are available online [see "On the web"].)
Step 1: The question
We begin the activity with a question for students to work through: "Climate scientists report that polar glaciers are shrinking, but what is the evidence for this, and what might be causing these changes?" As students review polar climate science, graph and analyze the ICESat ice surface elevation data, and critically respond to discussion questions, they formulate a response. By the end of the activity, they can answer the driving question: "Do you think Antarctica's PIG is a 'climate canary'?" In other words, could the PIG be an early warning of a larger problem, as canaries dying from poisonous gas were for coal miners?
Step 2: The process
Glaciers are key to Earth's climate system, reflecting the Sun's energy back into space as they cool the air above them. Glaciers are melting, scientists say, and for students to understand how we measure glacial change, they need a basic understanding of the glacier system. Students study the concepts in Figure 3, tracing the snow with their fingers from where it hits the ground to where it returns to the atmosphere. …