Ice-Albedo Feedback Loop Task

Standards Alignment:

• Performance Expectation: HS-ESS2-2
• Science and Engineering Practice: Developing and Using Models
• Disciplinary Core Ideas: ESS2.A: Earth Materials and Systems; ESS2.D: Weather and Climate
• Crosscutting Concept: Stability and Change

Simulation Link: Ice-Albedo Feedback Loop

Introduction

Earth’s climate system is complex, driven by the interactions between the atmosphere, hydrosphere, cryosphere, lithosphere, and biosphere. One critical mechanism that can amplify changes within this system is a positive feedback loop.

In this task, you will use the Ice-Albedo Feedback Loop simulation to investigate how a single change—an increase in greenhouse gas forcing—can trigger a cascade of events that dramatically alters Earth’s climate.

Part 1: Initial State and Albedo

1. Observe the Equilibrium State:
   • When you first open the simulation, do not start it yet. Record the initial values for:
     • Global Temperature: __ °C
     • Average Albedo: __
     • Ice Coverage (from the chart’s y-axis, approximately): __ %
   • Read the “Log Panel”. What does “System initialized at equilibrium” mean in terms of incoming solar radiation and outgoing heat?
2. Define Albedo:
   • Based on the “Understanding the Feedback Loop” section (located below the simulation model), what is albedo?
   • Which surface has a higher albedo: ice/snow or ocean water?

Part 2: Introducing a Change (The Trigger)

1. Adjust the Forcing:
   • Set the “Initial GHG Forcing” slider to “Moderate (+2 W/m²)”. This represents an increase in greenhouse gases, which trap more heat in the atmosphere.
   • Click “Start Simulation”.
   • Observe the “Global Temp” and “Avg Albedo” displays, as well as the log panel.
2. Data Collection:
   • Allow the simulation to run for several “Years” (x-axis on the chart).
   • Pause the simulation when the Ice Coverage reaches approximately 10% (between 8% and 12%).
   • Record the current values:
     • Time (Years): __
     • Global Temperature: __ °C
     • Average Albedo: __
3. Analyze the Initial Change:
   • What happened to the global temperature immediately after you increased the GHG forcing?
   • As the temperature rose, what happened to the ice caps in the “Earth System Model” visualization?

Part 3: The Feedback Loop in Action

1. Observe the Feedback:
   • Resume the simulation and let it run until all the ice melts.
   • As the ice melted, what happened to the “Avg Albedo” value? Why?
   • According to the log panel, what effect does a decreased albedo have on the rate of warming?
2. Graph Analysis:
   • Look at the “System Dynamics” chart. Describe the shape of the “Global Temp” curve. Is it a straight line (constant rate of change) or does it curve upward (accelerating rate of change)?
   • How does the shape of the temperature curve relate to the decreasing “Ice Coverage” curve?

Part 4: Constructing an Explanation

Using the evidence you gathered from the simulation, construct an explanation of the Ice-Albedo feedback loop.

Your explanation must include:

• A description of the initial trigger (the change that started the process).
• An explanation of how melting ice changes Earth’s overall albedo.
• A description of how this change in albedo affects the amount of solar energy absorbed by Earth.
• A conclusion stating whether this is a positive or negative feedback loop, and how it affects the overall stability of Earth’s climate system.