Climate Data, Trends & Attribution — Practice · Grade 12 Science

Chapter: Pollution, Carbon & Climate Evidence

What this practice covers

By the end of Climate Data, Trends & Attribution you should be able to:

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

Vocabulary used: anomaly, attribution, scenario.

Problem 1

Temperature changes.6°C in 30 years. Find average change per decade.
Hints

Write the relationship first; substitute with consistent units.

Answer and explanation

0.2 °C/decade

.6/30×10=.2.

Problem 2

Why does one cold winter not settle the global climate trend?
Answer and explanation

Its spatial and temporal scope is narrower than the long-term global statistical question.

Response criteria

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

Problem 3

An anomaly rises .8°C over 40 years. Find average change per decade.
Hints

List the given quantities, select a relationship, and check units before substituting.

Answer and explanation

0.2 °C/decade

.8/40×10=.2.

Problem 4

Why separate projections from observations?
Answer and explanation

Projections depend on future scenarios and models; observations describe measured past/current conditions.

Response criteria

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

Problem 5

A linear fitted trend is 0.15°C/decade. What change does it imply over 30 years within that model? Show the reasoning, not just the conclusion.
Hints

Data coverage, baseline and uncertainty affect interpretation.

Answer and explanation

0.15×3=0.45°C.

Problem 6

Why use anomalies with a declared baseline when combining climate records?
Hints

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

Answer and explanation

They compare deviations relative to a reference, reducing effects of different absolute local temperatures; the baseline must be clear.

Problem 7

Global inference needs coverage and independent measurement checksGlobal inference needs coverage and independent measurement checksIndicatorWhat it samplesUseful complementSurface temperatureNear-surface land/oceanestimatesSpatial coverage/methodchecksOcean heat contentEnergy stored in waterDepth-resolvedobservationsIce / sea levelPhysical responseindicatorsOther contributingmechanismsIndependent indicators do not mean identical instruments or coverage.
Original indicator/method comparison; the local annual file does not contain station coverage or uncertainty estimates.
Interpret the supplied visual. Can ocean heat content replace surface temperature one-for-one?
Answer and explanation

No. It measures a different aspect of the energy system and provides complementary evidence with its own coverage and uncertainty.

A global estimate combines observations with stated spatial coverage and analysis methods. Coverage bias can arise when sampled places differ systematically from missing places; measurement changes and calibration also require assessment. Independent datasets and indicators help test whether an apparent trend is an artifact of one method, although they need not measure exactly the same physical quantity. Do not invent a station-level error bar from the annual global values alone; use the source’s uncertainty methods.

No. It measures a different aspect of the energy system and provides complementary evidence with its own coverage and uncertainty.

Response criteria

  • Interpret labels, structures, axes, units and directions correctly.
  • Explain the physical or environmental relationship or mechanism.
  • Respect stated assumptions and distinguish observation from inference.

Problem 8

Two absolute global temperature estimates are 14.6°C and 15.0°C. Their baseline is 14.0°C, then changed to 14.2°C. Find both anomaly pairs and show whether their difference changes.
Answer and explanation

Original anomalies are 0.6 and 1.0°C; new anomalies 0.4 and 0.8°C. The difference remains 0.4°C, so a uniform baseline shift changes offset rather than physical change.

Original anomalies are 0.6 and 1.0°C; new anomalies 0.4 and 0.8°C.

The difference remains 0.4°C, so a uniform baseline shift changes offset rather than physical change.

Response criteria

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

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