Where did the change begin?
Labs / Geography
Planetary Energy Balance
A planet warms until the energy it radiates away exactly matches the sunlight it soaks up. Slide the sunlight, the reflectivity, and the greenhouse-gas amount — or drag on the sky to add gases — and watch the temperature hunt for the point where the incoming and outgoing arrows balance.
Labs / Geography / Planetary Energy Balance
Planetary Energy Balance
A planet warms until the energy it radiates away exactly matches the sunlight it soaks up. Slide the sunlight, the reflectivity, and the greenhouse-gas amount — or drag on the sky to add gases — and watch the temperature hunt for the point where the incoming and outgoing arrows balance.
Why it matters
Why explore this?
Geography explains how places, people, and Earth systems affect one another. This model lets you change one factor and watch its effects spread across space.
Explore
Try the model
in 238 W/m²out 238 W/m²net +0.0 W/m²T 15.0 °C≈ balanced
Investigate
Questions to test
Predict first, try it in the model, then use what you observe to answer.
What to try
- Push the greenhouse-gas slider up. Why does the surface keep warming even though the sunlight coming in never changed?
- Start from “Earth today” and slowly raise the albedo. Is there a point where a tiny nudge suddenly tips the whole planet into a frozen snowball?
- Once ice starts forming, notice the albedo climbing on its own. How does reflecting more sunlight make the planet even colder — a feedback that feeds itself?
- Try the “Faint young Sun” scenario. What would it take — more gases or less ice — to keep an early Earth from freezing solid?
- Can you find two very different greenhouse and albedo settings that land on the same surface temperature? What does that tell you about balance versus cause?
Explain
Make sense of what happened
Connect the pattern to place: identify where the change begins, where its effects appear, and which process links those locations.
Check
Before you leave
What spatial pattern appeared?
Which process connects the cause and effect?
If you can answer all three using evidence from the model, you understand the main idea. If not, return to Explore and change one setting at a time.