Climate Evidence, Trends & Projections — Drills · Grade 9 Science

Chapter: Oceans, Carbon & Climate

What these drills covers

By the end of Climate Evidence, Trends & Projections you should be able to:

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

Vocabulary used: anomaly, projection, baseline.

Problem 1

A mean is 9.8°C and the baseline is 10.2°C. Find anomaly.
Answer and explanation

-0.4 °C

9.8 − 10.2 = −0.4.

Problem 2

Name two checks before comparing climate graphs.
Answer and explanation

Check baselines, units, geographic coverage, time periods, and the variable being plotted.

Problem 3

Ice cores provide climate evidence mainly through
  1. fossils
  2. trapped air bubbles and isotope ratios in the ice
  3. rock layers
  4. tree rings
Answer and explanation

trapped air bubbles and isotope ratios in the ice

The bubbles sample ancient atmosphere directly and isotopes indicate temperature.

Problem 4

Tree rings record climate because ring width responds to
  1. the tree's age only
  2. growing-season conditions such as temperature and moisture
  3. soil colour
  4. wind direction
Answer and explanation

growing-season conditions such as temperature and moisture

Favourable seasons produce wider rings, so a sequence records year-by-year conditions.

Problem 5

A record shows 0.18 °C of warming per decade. How much warming over 50 years, in °C, to one decimal place?
Answer and explanation

0.9 °C

0.18 × 5 = 0.9 °C.

Problem 6

A projection differs from a prediction because a projection states
  1. a certainty
  2. what follows if a given scenario holds
  3. the past
  4. an opinion
Answer and explanation

what follows if a given scenario holds

Projections are conditional on assumptions about future emissions and policy.

Problem 7

Explain why a single very hot year is weak evidence of a trend.
Answer and explanation

Year-to-year variation is large for reasons unrelated to any long-term change, so one extreme value can occur within a stable climate. A trend is a change in the average over decades, which requires many years of data to establish. The useful question about a hot year is whether such years are becoming more frequent, which the longer record can answer.

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

Why do climate scientists report a range of projected warming rather than one figure?
Answer and explanation

The outcome depends on future emissions, which are a human choice rather than a measurable quantity, and on how sensitively the climate responds, which is known only within a range. Reporting a range with the scenario attached states both sources of uncertainty honestly and lets decisions be made with the spread visible, which a single number would conceal.

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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