Impacts—Melting Ice

Summary: One indicator of climate change is the increased melting of sea ice and glaciers on land. While many people hold a common misconception that the melting of sea ice will increase sea level, sea ice melting actually contributes very little to sea level rise. In contrast, melting land ice could contribute to sea level rise. In this activity, students conduct an experiment to demonstrate which masses of melting ice pose contribute most to sea level rise and why. Then they learn how the absence of ice promotes further melting through a positive feedback loop.

Concepts to teach:

• Crosscutting Concepts
  • Cause and Effect, Structure and Function
    
• Disciplinary Core Ideas
  • ESS2.A - Earth Materials and Systems
  • ESS2.C - The roles of water in Earth's surface processes
• Science Practices
  • Planning and carrying out investigations, Analyzing and interpreting data

Goals:

1. Increasing rates of melting ice on land and sea are an indicator of global climate change
2. Melting land-based ice contributes to sea level rise, while melting sea ice does not
3. Ice melt results in darker sea and land surfaces, which further absorb heat and cause a warming feedback loop

Standards: NGSS Performance Expectations

• HS-ESS2-2. Analyze geoscience data to make the claim that one change to Earth's surface can create feedbacks that cause changes to other Earth systems.
• HS-ESS2-5. Plan and conduct an investigation of the properties of water and its effects on Earth materials and surface processes.

Specific Objectives:
Students will be able to:

1. Describe the effects melting sea ice and land ice have (or do not have) on sea level.
2. Demonstrate that ice is less dense than water.
3. Demonstrate that ice displaces water equal to the mass of the ice.
4. Describe the Albedo Climate Feedback Mechanism.

Activity Links and Resources:

• EPA's Sea Level: On the Rise, part 2—Students create a model representing sea ice and land ice and measure the effects on the water level when the ice melts. This activity can be performed by student groups.
• How has Arctic sea extent changed over past decades? Graphic visualizations show changes in sea ice cover.
  • Climate Central Video—How Do We Know: Shrinking Arctic Sea Ice
  • NOAA's Global Science Investigator—View an animation of September minimum Arctic sea ice extent for each year from 1979–2004.
  • Arctic Sea Ice Minimum Volumes 1979-2012 from Andy Lee Robinson. More graphics here
• Investigating Albedo—In this lesson from the Environmental Initiative at Lehigh University, students conduct a simple classroom experiment that demonstrates how the color of a surface influences its ability to reflect or absorb heat.
  • Reading: Albedo Climate Feedback Mechanism: Melting ice on land or sea result in darker surfaces that absorb light and induces further melting.
  • Online Activity: How does land cover affect global temperature?

Assessment:

• Why do scientists track sea ice extent in the Arctic?
• How will melting Arctic sea ice affect sea level?
• How will melting glaciers and ice on Greenland and Antarctica affect sea level?
• Discuss the implications the albedo feedback mechanism has on ice melt.