Lesson 5 of 6 · Climate
Converging Lines of Evidence
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🎯 Your mission
Master the concept. Use it tomorrow.
⚡ The twist
Today's mountain was yesterday's ocean floor.
What you'll learn
Surface thermometers, ocean heat content, sea level, glacier mass, sea ice extent and the shifting ranges of species are measured by different instruments, by different research groups, with entirely different sources of error. They agree. A fault in the thermometer network would not move the glacier record, and an error in satellite altimetry would not change where the birds nest — which is why convergence across independent records is stronger evidence than any single record, however long it runs.
Key words
line of evidence
One independent kind of measurement bearing on a question, with its own instruments and its own errors.
convergent evidence
Several independent lines pointing to the same conclusion, which no single shared error could produce.
Make a hypothesis first
Guess: where will the water go first?
Say your guess out loud — then find out if you were right.
Step 1 of 4 · Read
Think about what you just learned: say what "line of evidence" and "convergent evidence" mean in your own words before you start.
Step 2 of 4 · Do
Plot six independent climate indicators on a shared timeline, normalising each to its own 1961-1990 baseline. Mark where they agree and where they do not, and write down what a fault in any one record would have to do to the others.
Step 3 of 4 · Observe
Record what actually happened, including anything that did not match what you expected.
Step 4 of 4 · Record
Write a conclusion that answers the question this lesson opened with, and state your uncertainty.
Question 1 of 3
Question 2 of 3
Question 3 of 3
Mind = blown
🌋 There are 1,500 active volcanoes on Earth right now.
Nice work!
You got 0 of 3 right.
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✨ More to explore
🌍 Where you see this in real life: Today's weather, tomorrow's beach, next century's coastline — all this.
🏆 Stretch challenge (try it this week): Look at the sky for 5 minutes and try to predict tomorrow's weather.
👨👩👧 For the dinner table: “What's the slowest change you can think of?”
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Converging Lines of Evidence
Master the concept. Use it tomorrow.
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Print the whole Climate track
All 8th Grade Climate lessons as a printable PDF, with worksheets and answer keys.