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Date May 2022 Marks available 1 Reference code 22M.2.SL.TZ1.3
Level Standard level Paper Paper 2 Time zone Time zone 1
Command term Calculate Question number 3 Adapted from N/A

Question

The graph shows the mean annual changes in global temperatures between 1880 and 2014. The mean temperature from 1951 to 1980 was used as the value of zero change in temperature.

[Source: National Aeronautics and Space Administration, n.d. GISS Surface Temperature Analysis (v3). [online]
Available at: https://data.giss.nasa.gov/gistemp/graphs_v3/ [Accessed 20 August 2019].]

Calculate the increase in mean global temperature between 1880 and 2010.

.......... °C

 

 

[1]
a.

Outline how changes in temperature over short time periods could give a misleading impression of changes to the Earth’s climate. 

[1]
b.

Explain how increased carbon dioxide in the air leads to the greenhouse effect.

[3]
c.

Markscheme

0.87; (accept values between 0.8 and 0.9)

a.

short-term reading could show global temperatures falling while the trend is rising
OR
fluctuations from year to year may not show long-term trend;

b.
  1. short wave radiation from sun passes through atmosphere / is not absorbed by CO2;
  2. infrared/long wave (radiation) / heat emitted from/released from (surface of) Earth;
  3. CO2 in the atmosphere absorbs infrared/long wave (radiation)/heat / cannot pass through the greenhouse gases;
  4. this results in warm/increased temperatures on Earth/global warming;

Do not accept “reflected” for mpb.

c.

Examiners report

Many candidates got the calculations right.

a.

Answers to this question suffered due to poor expression of an answer. Other candidates answers were succinct and to the point as they used the data to make the point clear.

b.

There were elegant answers to this question demonstrating a high level of understanding. Many other candidates mixed up all sorts of ideas here, including the idea of ozone being a cause of global warming and stating as a "fact" that heat travels from the sun to the earth. Among the confused ideas was the notion that carbon dioxide is a toxic pollutant.

c.

Syllabus sections

Core » Topic 4: Ecology » 4.4 Climate change
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