23  Unit 4: Climate Feedbacks 5E

What is causing global temperatures to rise, and why is the Arctic warming at almost 4 times the rate as the rest of the globe?

Author

Earth & Space Science

23.1 🌍 Current CO₂ Levels

The most recent daily average atmospheric CO₂ concentration at Mauna Loa is ppm.

🌍 Current Atmospheric CO₂

The most recent daily average concentration of CO₂ at Mauna Loa Observatory () is:

ppm

Data sourced from NOAA Global Monitoring Laboratory.

HS-ESS2-2 HS-ESS2-4 HS-ESS2-6 Time: 7-9 Days 🧠 Quiz & Evaluate ↓

24 Investigative Phenomenon

24.1 🌡️ Arctic Amplification

The globe is warming, and the average temperature of the Arctic is increasing at almost 4 times the rate as the rest of the globe.

24.1.1 Driving Questions:

  • What is causing global temperatures to rise today?
  • Why is the Arctic warming almost 4x faster than the rest of the globe?
  • How do feedbacks (like greenhouse gases and ice) amplify or reduce change?
  • How do greenhouse gas increases connect to glacial cycles and current warming?

25 Engage: Arctic vs Global Warming

What is happening to temperatures and Arctic ice today? Use the graph below to compare warming in the Arctic to the global average and surface student questions about the current climate change that orbital factors did not explain in the previous lesson.

Before looking at the data, make a prediction:

25.0.1 🤔 Initial Questions

  1. How much faster is the Arctic warming compared to the global average?
  2. What evidence from the graph suggests the Arctic is changing more rapidly?
  3. What changes in the Arctic might amplify or reduce this warming trend?

25.1

25.2 Greenhouse Feedback Interactive Plot

Turn on/off graph layers:

26 Explore Part 1: The Greenhouse Effect

How do carbon dioxide levels in the air both impact and change as a result of Earth’s systems? Use the simulation to gather evidence about the causal mechanism behind the correlation between atmospheric CO₂ levels and climate factors like temperature.

26.0.1 Carbon Cycle Model: Pre vs. Post Industrial

Use the sliders below to simulate the flow of carbon. 1. Keep Fossil Fuel Burning at 0 to see the Pre-Industrial equilibrium. 2. Increase the burning rate to see how the Atmosphere reservoir changes over time.

26.1 Modeling the Effect of the Carbon Cycle on Temperature

Explore how greenhouse gases trap heat in Earth’s atmosphere:

PhET Simulation: Greenhouse Effect Click to open in a new tab (works even if embeds are blocked) Launch Sim Tip: if your school network blocks the site, use the link below.
Open the simulation PhET sim page

Some previews (and some LMS pages) block external iframes, so this lesson uses a click-to-open launch card instead of an embed.

26.1.1 🔬 Simulation Investigation Tasks

Task 1: Explore the Greenhouse Effect 1. Start with “Waves” mode to see how infrared radiation interacts with greenhouse gases 2. Compare Earth’s temperature with NO greenhouse gases vs. with greenhouse gases 3. Record the equilibrium temperature for each scenario

Task 2: Compare Different Atmospheres 1. Try the Ice Age atmosphere setting 2. Try the 1750 (pre-industrial) setting 3. Try the “Today” setting 4. Record how temperature changes with different CO₂ levels

Task 3: Photon Absorption 1. Switch to “Photons” mode 2. Observe what happens when infrared photons encounter CO₂ molecules 3. Explain why more CO₂ = more warming

26.2 CO₂ and Temperature: The Evidence

26.2.1 Ice Core Data: 800,000 Years of CO₂ and Temperature

Code 
co2_historical_data = [
  {year: 1750, co2: 278, emissions: 0.01},
  {year: 1800, co2: 282, emissions: 0.03},
  {year: 1850, co2: 285, emissions: 0.2},
  {year: 1900, co2: 296, emissions: 1.95},
  {year: 1950, co2: 311, emissions: 6.0},
  {year: 1970, co2: 325, emissions: 15.0},
  {year: 1990, co2: 354, emissions: 22.7},
  {year: 2000, co2: 369, emissions: 25.4},
  {year: 2010, co2: 389, emissions: 33.1},
  {year: 2022, co2: 418, emissions: 37.5}
]

// 2. THE CHART
vl.layer(
  // First Layer: Blue Line (CO2)
  vl.markLine({color: "#0ea5e9", strokeWidth: 3})
    .encode(
      vl.x().fieldQ("year").title("Year").axis({format: "d"}),
      vl.y().fieldQ("co2").scale({domain: [260, 420]}).title("Atmospheric CO2 (ppm)")
    ),

  // Second Layer: Grey Line (Emissions)
  vl.markLine({color: "#9ca3af", strokeWidth: 3})
    .encode(
      vl.x().fieldQ("year"),
      vl.y().fieldQ("emissions").axis({orient: "right"}).title("Emissions (Gt)")
    )
)
.data(co2_historical_data) // Data is attached to the *entire layer*
.resolve({scale: {y: "independent"}}) // This splits the Y axes
.width(600)
.height(400)
.render()
(a)
(b)
Figure 26.1

26.2.2 ✅ Data Analysis

  1. What is the highest CO₂ level in the past 800,000 years (before humans)?
  2. What is today’s CO₂ level?
  3. How does today’s CO₂ compare to the natural range?
  4. What pattern do you notice between CO₂ and temperature in the ice core record?
  5. Based on these data, make a claim about how CO₂ levels and temperature are related.

27 Explain Part 1: CO₂–Temperature Connection

How are atmospheric carbon dioxide levels and temperatures related? Construct an explanation using evidence from the simulation, ice core data, and text, describing how human activities have increased greenhouse gas levels and how that drives warming.

28 Explore Part 2: The Albedo Effect

How is the icy surface of the poles changing, and what does that do to Earth’s temperature? Analyze albedo models and datasets to figure out how different surfaces change the surrounding system and impact temperature.

28.1 What is Albedo?

Albedo is the measure of how much light a surface reflects. It ranges from 0 (absorbs all light) to 1 (reflects all light).

June 14, 2023 (base image)
July 24, 2023 (overlay image)
June 14, 2023
July 24, 2023

Drag the slider left and right to compare the images

Figure 28.1: Interactive comparison of Frederiksdal Glacier, Greenland between June 14 and July 24, 2023, showing dramatic ice loss over 40 days.

28.2 Interactive: Ice-Albedo Feedback Simulation

28.3 🔬 Lab Activity: Albedo Investigation

Analysis Questions: - Which container heated up faster? Why? - How does this relate to ice-covered vs. ice-free Arctic? - Predict what happens as Arctic ice melts.

Code 
data = [
  // Black Paper
  { time: 0, temperature: 20, paperColor: "Black Paper" },
  { time: 5, temperature: 31, paperColor: "Black Paper" },
  { time: 10, temperature: 36, paperColor: "Black Paper" },
  { time: 15, temperature: 42, paperColor: "Black Paper" },
  { time: 20, temperature: 48, paperColor: "Black Paper" },
  { time: 25, temperature: 54, paperColor: "Black Paper" },
  { time: 30, temperature: 58, paperColor: "Black Paper" },

  // Blue Paper
  { time: 0, temperature: 20, paperColor: "Blue Paper" },
  { time: 5, temperature: 24, paperColor: "Blue Paper" },
  { time: 10, temperature: 32, paperColor: "Blue Paper" },
  { time: 15, temperature: 37, paperColor: "Blue Paper" },
  { time: 20, temperature: 46, paperColor: "Blue Paper" },
  { time: 25, temperature: 49, paperColor: "Blue Paper" },
  { time: 30, temperature: 53, paperColor: "Blue Paper" },

  // Green Paper
  { time: 0, temperature: 20, paperColor: "Green Paper" },
  { time: 5, temperature: 21, paperColor: "Green Paper" },
  { time: 10, temperature: 27, paperColor: "Green Paper" },
  { time: 15, temperature: 32, paperColor: "Green Paper" },
  { time: 20, temperature: 37, paperColor: "Green Paper" },
  { time: 25, temperature: 42, paperColor: "Green Paper" },
  { time: 30, temperature: 45, paperColor: "Green Paper" },

  // White Paper
  { time: 0, temperature: 20, paperColor: "White Paper" },
  { time: 5, temperature: 20.5, paperColor: "White Paper" },
  { time: 10, temperature: 21, paperColor: "White Paper" },
  { time: 15, temperature: 22, paperColor: "White Paper" },
  { time: 20, temperature: 24, paperColor: "White Paper" },
  { time: 25, temperature: 25, paperColor: "White Paper" },
  { time: 30, temperature: 26, paperColor: "White Paper" },
]

// Create the plot
Plot.plot({
  title: "Effect of Paper Color on Temperature Over Time",
  subtitle: "Data from Earth and Space Science Unit 4 - Climate Change",
  y: {
    label: "Temperature (°C)",
    domain: [0, 60],
    grid: true
  },
  x: {
    label: "Time (Minutes)",
    domain: [0, 30],
    grid: true,
    ticks: 5 // Ensure ticks are every 5 minutes
  },
  color: {
    legend: true,
    //Map the paper color names to actual colors.
    //Using a light grey for "White Paper" for visibility.
    domain: ["Black Paper", "Blue Paper", "Green Paper", "White Paper"],
    range: ["black", "blue", "green", "#aaa"] 
  },
  marks: [
    // Draw the lines
    Plot.lineY(data, { x: "time", y: "temperature", stroke: "paperColor", strokeWidth: 2 }),
    // Add dots at each data point
    Plot.dot(data, { x: "time", y: "temperature", fill: "paperColor", r: 4 })
  ]
})

28.4 🏙️ Local Connection: The Urban Heat Island Effect

Why is the city often hotter than the countryside in the summer?

  • Asphalt & Concrete: Roads and buildings have low albedo (0.04–0.12), absorbing most sunlight.
  • Lack of Vegetation: Trees (albedo ~0.15–0.25) cool the air through evaporation, but cities have fewer of them.
  • The Result: Cities can be 1–3°C (2–5°F) hotter than rural neighbors during the day and up to 12°C (22°F) hotter at night!

Think about it: Why are many school buses and roofs painted white?

29 Glacial Retreat and Sea Level Rise

PBS LearningMedia: Glacier Photos Interactive slider comparing glacier retreat over time Open Interactive Click to launch PBS resource (opens in new tab)
Launch PBS Glacier Interactive

PBS LearningMedia resources work best when opened in a new browser tab. If blocked, check your school network settings.

Figure 29.1: Interactive glacier photo comparison showing dramatic glacial retreat over time. Drag the slider to compare images. (Source: PBS LearningMedia)

30 Explain Part 2: Feedback Loops in the Climate System

30.1 🔄 Understanding Climate Feedbacks

A feedback loop occurs when the output of a system affects its input, creating a cycle.

30.1.1 Positive Feedback (Amplifying)

Makes changes BIGGER - the system amplifies itself

30.1.2 Negative Feedback (Stabilizing)

Makes changes SMALLER - the system stabilizes itself

30.2 Interactive Feedback Loop Diagram

30.4 Arctic Sea Ice Decline

30.4.1 ✅ Check Your Understanding

  1. What type of feedback is the ice-albedo feedback? (positive or negative)
  2. Why does exposing dark ocean water lead to more warming?
  3. Calculate: If ice (albedo 0.6) is replaced by ocean (albedo 0.06), how much more energy is absorbed?
  4. How does the ice-albedo feedback help explain why the Arctic warms faster than the rest of the planet?

31 Elaborate: Greenhouse Gases + Albedo Together

How do greenhouse gases and albedo interact? Model the combined effects of greenhouse gas and albedo feedback loops to explain the rapid rate of change of Earth’s temperature and make claims about what could happen in the future based on historical and current evidence.

31.1 CO₂ and Human Activity

31.2 Where Does the CO₂ Come From?

31.3 CO₂ Growth Over Time

31.3.1 💡 Key Ideas: Climate Feedbacks

  1. The greenhouse effect explains why increasing CO₂ leads to global warming
  2. Albedo is the tendency of a surface to reflect or absorb radiation
  3. Ice has high albedo (~60%) compared to seawater (~6%)
  4. As ice melts, more radiation is absorbed, causing more warming → positive feedback
  5. Arctic amplification (4x faster warming) is explained by ice-albedo feedback
  6. Multiple feedback loops (ice-albedo, water vapor, permafrost) amplify climate change
  7. Human activities have dramatically increased CO₂ levels beyond natural ranges

32 Evaluate: Modeling Climate Feedbacks

32.1 📊 Performance Task Check-In

Using what you’ve learned, you can now explain:

  1. Why scientists are confident humans are causing climate change:
    • CO₂ levels are far beyond natural range (420 ppm vs. max 280 ppm)
    • The timing matches industrialization
    • Natural factors (Milankovitch cycles, solar output) can’t explain current warming
  2. Why the Arctic is warming so fast:
    • Ice-albedo feedback amplifies warming
    • As ice melts, dark ocean absorbs more energy
    • This creates a self-reinforcing cycle
  3. How feedbacks make climate change worse:
    • Ice-albedo: melting ice → more absorption → more melting
    • Water vapor: warming → more evaporation → more greenhouse effect
    • Permafrost: warming → methane release → more warming
  4. Claim with evidence: Use data from this lesson to explain how human activities are driving destabilizing feedback loops today.

32.2 Create Your Feedback Diagram

32.2.1 📝 Activity: Draw Your Own Feedback Loop

Create a diagram showing how multiple feedback loops interact:

  1. Start with “Human emissions increase CO₂”
  2. Show how this leads to warming
  3. Include ice-albedo feedback
  4. Include water vapor feedback
  5. Show how they connect and amplify each other
  6. Indicate which parts are observed data vs. projected consequences

Guiding Questions: - Where do humans enter this system? - Which parts of the cycle have we already observed? - What might happen if Arctic ice disappears entirely in summer? - Are there any potential negative (stabilizing) feedbacks?

33 Interactive Carbon Cycle Flow Diagram

This visualization shows how carbon flows between Earth’s major reservoirs changed after the Industrial Revolution.

34 Feedback Loop Visualization

This visualization shows how positive feedback mechanisms amplify climate change through interconnected processes.

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