Block 2: Earth's Energy Balance: The Math
Three numbers, three worlds. Average surface temperature: Venus 464°C, Earth 15°C, Mars −63°C. Venus is closer to the Sun than Earth, but not that much closer.
Task: What could explain a 449-degree gap between neighbors? Write one guess. Today's math answers it.
Answer in your Field Notebook, dated.
I can explain the role of albedo + atmospheric absorption + thermal output in the energy-balance equation, estimate planetary temperature under different GHG concentrations, and explain why this math works for Earth but produces very different outputs for Venus or Mars.
I can use a model to show how energy in vs. energy out sets Earth's climate.
"Use a model to describe how variations in the flow of energy into and out of Earth's systems result in changes in climate."
Where this runs:
- U4 B1: The Greenhouse Effect: How Earth Keeps Warm Enough
- U4 B2: Earth's Energy Balance: The Math ← you are here
- U4 B4: Human Acceleration of Carbon + The Warming Signal
- U4 B8: Tipping Points + Feedback Loops
Assessed:
Chennai Climate Brief: the science sections (K/U components)
On track looks like:
Your brief's physics section traces an energy flow, not just names 'greenhouse effect.'
What today is about
Block 1 was the qualitative version. Today is quantitative.
The energy-balance equation (solar input minus albedo-reflected, plus atmospheric trapping, equals thermal output) has a real numerical answer. Plug in the numbers: you get a planetary temperature. Plug in different greenhouse-gas concentrations: you get different temperatures. This is how climate science predicts. Not by hand-waving; by math.
Today also connects directly back to Unit 1. The same energy-balance logic you'll work through here applies to Earth, Mars, and Venus in the Goldilocks Report habitability framework. Now you have the equations behind the framework, and the Habitability Zone Calculator becomes a checkable model rather than a black box.
Before you start the work
Start with the Watch: projected and recorded for replay. The Interact is the habitability calculator you practise the math on, and the Read is your reference.
Today's work: choose one path
All four paths end the same: three temperature calculations + a 2-sentence sensitivity claim. The path you pick is about how deep you go on the assumptions.
Open your Class Notebook and type today's entry header as Heading 2:
A: Jan 20 | U4 B2 | Earth's Energy Balance: The MathB: Jan 21 | U4 B2 | Earth's Energy Balance: The Math
What you're submitting today
Three numbers + two sentences. The numbers have to be correct; the sentences have to be precise.
Three Earth temperatures (at 280 / 420 / 560 ppm CO₂) with work shown. Then a 2-sentence claim about temperature-sensitivity: "If CO₂ doubles from 280 to 560 ppm, planetary temperature changes by ___ °C, which is consistent / inconsistent with IPCC equilibrium climate sensitivity estimates of 2-4°C because ___."
Submit via Google Classroom (link posted in August)One question before you leave
Three to five minutes. Your answer is saved to your reflection journal, where you can read back everything you have written this year.
Surface the step that needs Block 3 to build on.
Today's reflection is in Google Classroom, under Reflection Journal.
Link posted in AugustSign in with your school account. Your teacher can see what you write here.