Forcing, Feedback and Climate Sensitivity · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Pushes, replies, and sensitivity

Science · Earth's Systems · ages 17-18
Name ______________________   Date ____________

  1. Air warms a little. What does extra water vapour do next?

    • It leaves the atmosphere at once
    • It blocks all sunlight and freezes Earth
    • It traps more heat and warms more

  2. Volcanic particles block sunlight, then extra vapour traps heat. Which is the forcing?

    • The blocked sunlight, which started it
    • The extra vapour, since it came first
    • Both are feedbacks, since both involve air

  3. Melting ice slows warming because dark water reflects more sunlight.

    Circle one:   True   False

  4. Ice melts and exposes dark ocean. Which way does this push temperature?

    • Down, since water evaporates at once
    • Up, since dark absorbs more heat
    • Nowhere, since color cannot matter

  5. A big eruption cools Earth briefly. Why call it a push from outside?

    • Eruptions never affect the energy balance
    • Volcanoes sit outside planet Earth
    • It starts the change from outside

  6. What does climate sensitivity summarize?

    • How much warming a push causes after feedbacks
    • How thermometers react to sunlight
    • How many clouds appear each day

  7. A glacier retreats as greenhouse gases rise. How do you split forcing from feedback?

    • The retreat is the forcing and gases are the feedback
    • Added gases are the forcing and reflectivity changes are the feedback
    • Both are forcings, so no split is needed

  8. A friend says the sensitivity range exists because CO2 was never measured. What is wrong?

    • CO2 has never been measured anywhere
    • The range comes mainly from clouds, which can warm or cool
    • A range means models show zero warming
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Pushes, replies, and sensitivity W1-mt_os28W6fEkW-s1

  1. It traps more heat and warms more · Vapour is a greenhouse gas, so more of it warms further.
  2. The blocked sunlight, which started it · The outside push is the forcing, and the vapour reply is the feedback.
  3. False · Dark surfaces absorb more sunlight, so melting speeds warming.
  4. Up, since dark absorbs more heat · Lower reflectivity means more absorbed sunlight and more warming.
  5. It starts the change from outside · The particles arrive independently, then the system answers.
  6. How much warming a push causes after feedbacks · It totals the push plus every amplifying and damping reply.
  7. Added gases are the forcing and reflectivity changes are the feedback · Gases start the change, and the ice reply feeds back through reflectivity.
  8. The range comes mainly from clouds, which can warm or cool · Cloud uncertainty, not missing CO2 data, widens the range.
Worksheet · LightMySky