Climate & the Greenhouse Effect — Drills · Grade 9 Science

Chapter: Oceans, Carbon & Climate

What these drills covers

By the end of Climate & the Greenhouse Effect you should be able to:

8 questions, multiple choice, numeric and written answer, each with a worked explanation.

Vocabulary used: climate, greenhouse effect, greenhouse gas, global warming.

Problem 1

The greenhouse effect occurs because certain gases
  1. block incoming sunlight
  2. absorb and re-emit outgoing infrared radiation
  3. cool the surface
  4. destroy ozone
Answer and explanation

absorb and re-emit outgoing infrared radiation

They are largely transparent to incoming sunlight but absorb the infrared Earth radiates back.

Problem 2

Which is a greenhouse gas?
  1. Nitrogen
  2. Oxygen
  3. Carbon dioxide
  4. Argon
Answer and explanation

Carbon dioxide

Carbon dioxide, methane and water vapour absorb infrared; nitrogen and oxygen largely do not.

Problem 3

Weather and climate differ in that climate describes
  1. today's conditions
  2. long-term average conditions and their variability
  3. only temperature
  4. only rainfall
Answer and explanation

long-term average conditions and their variability

Climate is the statistics of weather over decades.

Problem 4

Without any greenhouse effect, Earth's surface would be
  1. much warmer
  2. about the same
  3. much colder
  4. unchanged in temperature but darker
Answer and explanation

much colder

The natural greenhouse effect keeps the surface well above what sunlight alone would produce.

Problem 5

A global mean temperature rises from 14.0 °C to 15.1 °C. What is the increase in °C, to one decimal place?
Answer and explanation

1.1 °C

15.1 − 14.0 = 1.1 °C.

Problem 6

A cold winter in one country is weak evidence against global warming because
  1. winters are always cold
  2. a single place over one season is not a global average over decades
  3. temperature cannot be measured
  4. warming only affects summers
Answer and explanation

a single place over one season is not a global average over decades

Climate claims are about long-term global averages, so local short-term variation does not test them.

Problem 7

Explain the difference between the natural greenhouse effect and the enhanced greenhouse effect.
Answer and explanation

The natural effect is the warming produced by greenhouse gases that have always been present, and it keeps Earth habitable rather than frozen. The enhanced effect is the additional warming from the extra greenhouse gases added since industrialisation, chiefly carbon dioxide from burning fossil carbon. The mechanism is the same; what has changed is the concentration and therefore the strength.

Response criteria

  • State a scientifically accurate conclusion.
  • Show the data, mechanism, or calculation that supports it.
  • Include units, conditions, or limits where relevant.

Problem 8

Explain why scientists use global averages over decades rather than local records over years.
Answer and explanation

Local weather varies enormously from year to year for reasons unrelated to any long-term trend, so a short local record is dominated by that noise. Averaging across the globe cancels regional fluctuations, and averaging over decades cancels year-to-year variation, leaving the underlying trend visible. The question being asked is about the climate system as a whole, so the measurement has to match that scale.

Response criteria

  • State a scientifically accurate conclusion.
  • Show the data, mechanism, or calculation that supports it.
  • Include units, conditions, or limits where relevant.

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