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

Chapter: Oceans, Carbon & Climate

What this practice covers

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

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

Vocabulary used: anomaly, projection, baseline.

Problem 1

A mean is 12.4°C and its baseline is 12.0°C. Find the anomaly.
Answer and explanation

0.4 °C

12.4 − 12.0 = 0.4.

Problem 2

A cold week disproves a multi-decade warming trend.
  1. True
  2. False
Answer and explanation

False

Short-term variability and long-term trends describe different scales.

Problem 3

Why state an emissions scenario with a projection?
Answer and explanation

The projected outcome depends partly on assumptions about future emissions.

Problem 4

An annual temperature is 14°C; baseline A is 12°C and B is 13°C. Find both anomalies. Explain the reasoning in your own words.
Answer and explanation

+2°C relative to A and +1°C relative to B; the actual temperature is unchanged.

Subtract each reference from the measurement.

14−12=+2°C; 14−13=+1°C.

Response criteria

  • Use the stated conditions.
  • Show the evidence or calculation.
  • Explain the conclusion and any stated limitation.

Problem 5

A dataset reports 0.3°C per decade. What does that unit mean? Show the reasoning, not just the conclusion.
Hints

Distinguish endpoint change from a fitted trend and attribution.

Answer and explanation

Average change of 0.3°C per 10 years under the stated trend estimate, not exactly that change every year.

Problem 6

Why compare observations with models that include and exclude different drivers?
Hints

State what the supplied observations or conditions establish, and separate that from any assumption.

Answer and explanation

The comparison helps test whether proposed drivers reproduce the pattern, rather than inferring cause from a trend alone.

Problem 7

Read an actual global temperature-analysis recordRead an actual global temperature-analysis recordGlobal annual anomaly (°C; 1951–1980 baseline)-0.200.40.81.21970198019902000201020202025YearNASA GISS/GISTEMP v4 • complete selected annual entries 1970–2024
Original plot of actual NASA GISTEMP v4 annual global Land–Ocean estimates, all 55 selected years from 1970–2024. Anomalies in °C relative to 1951–1980; record accessed 2026-10-13. Citation: GISTEMP Team (2026) and Lenssen et al. (2024). Later years are outside this selected interval, and the graph alone does not establish causal attribution. NASA GISS/GISTEMP v4 — source and analysis · Lenssen et al. (2024) — observational uncertainty
Interpret the supplied visual model. What does the 2024 value 1.28 °C mean, and does this graph say every place was exactly 1.28 °C warmer?
Answer and explanation

It is the estimated global annual Land–Ocean anomaly of +1.28 °C relative to the 1951–1980 baseline in this accessed record. Regional and daily changes vary; it is not the same increase everywhere.

Read the actual annual points and their stated baseline. The plot’s upper values are anomalies, not Earth’s absolute surface temperature.

It is the estimated global annual Land–Ocean anomaly of +1.28 °C relative to the 1951–1980 baseline in this accessed record. Regional and daily changes vary; it is not the same increase everywhere.

Response criteria

  • Read the labeled quantities, reference frame or objects correctly.
  • Explain the relation between the visual evidence and the mechanism.
  • Keep the drawing’s stated assumptions and limits in the conclusion.

Problem 8

An observed annual temperature is 16.4 °C and its matched baseline is 15.8 °C. Find the anomaly. A separate future scenario curve gives +1.2 °C at year 20. Explain what must be supplied before comparing the values.
Answer and explanation

The observed anomaly is +0.6 °C. The projection must specify the same variable, region, baseline and averaging interval, plus its scenario/assumptions. An observation and a conditional future model remain different kinds of evidence.

Subtract 16.4−15.8 = +0.6 °C.

Check matching baseline, coverage and time definition.

Identify projection assumptions and distinguish modeled future values from observations.

Response criteria

  • Use the stated measurements or conditions, with correct units.
  • Connect the result to the physical mechanism or evidence relationship.
  • Identify the assumption, model limit or further evidence requested.

Problem 9

Read an actual global temperature-analysis recordRead an actual global temperature-analysis recordGlobal annual anomaly (°C; 1951–1980 baseline)-0.200.40.81.21970198019902000201020202025YearNASA GISS/GISTEMP v4 • complete selected annual entries 1970–2024
Original plot of actual NASA GISTEMP v4 annual global Land–Ocean estimates, all 55 selected years from 1970–2024. Anomalies in °C relative to 1951–1980; record accessed 2026-10-13. Citation: GISTEMP Team (2026) and Lenssen et al. (2024). Later years are outside this selected interval, and the graph alone does not establish causal attribution. NASA GISS/GISTEMP v4 — source and analysis · Lenssen et al. (2024) — observational uncertainty
The complete selected NASA annual record has anomalies +0.03 °C in 1970 and +1.28 °C in 2024, on the same 1951–1980 reference. Find the endpoint change. Explain why this two-value subtraction is neither a fitted trend rate nor proof that every year and place warmed by that amount. Use the complete selected table to find a pair of consecutive years with a decrease.
Answer and explanation

The endpoint change is 1.28−0.03 = +1.25 °C in the global annual Land–Ocean anomaly. The common reference cancels. A fitted rate needs a specified method across the record and time units; this subtraction is an endpoint change. One adjacent decrease is 1970 (+0.03 °C) to 1971 (-0.08 °C), a change of -0.11 °C. Local/daily changes differ from the global annual estimate, and the graph alone is not a complete causal attribution.

Use the same variable, reference and annual definition for both values.

Subtract 1.28−0.03 = +1.25 °C; describe it as an endpoint change across the selected interval.

Inspect adjacent entries in the complete table to show annual variation.

Distinguish a global annual statistical estimate from local conditions, a fitted rate and a causal analysis.

Response criteria

  • Calculate +1.25 °C with the correct endpoint and baseline interpretation.
  • Give a valid adjacent-year decrease from the supplied table.
  • Distinguish endpoint change, fitted rate, local variation and causal attribution.

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