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Date	November 2015	Marks available	2	Reference code	15N.1.SL.TZ0.6
Level	Standard Level	Paper	Paper 1	Time zone	Time zone 0
Command term	Describe	Question number	6	Adapted from	N/A

Question

Figure 4(a): Changes in Arctic sea ice in a typical year.

Figure 4(a)

[Source: Images courtesy of the National Snow and Ice Data Center, University of Colorado, Boulder]

Figure 4(b): Arctic sea ice extent.

Figure 4(b)

[Source: National Snow and Ice Data Center. Arctic Sea Ice News & Analysis / Charctic Interactive Sea Ice Graph. http://nsidc.
org/arcticseaicenews/charctic-interactive-sea-ice-graph/. Accessed November 18, 2015.]

Figure 4(c): Arctic sea ice extent 1979–2012.

[Source: Data source: http://nsidc.org]

Identify one factor that may be causing long-term changes in sea ice cover.

[1]

a.i.

Calculate the percentage change in sea ice cover from March 1979 to March 2012 and from September 1979 to September 2012 in Figure 4(c).

[2]

a.ii.

Describe the trend seen in the sea ice cover data in Figure 4(b).

[2]

a.iii.

Markscheme

climate change/global warming;
Milankovitch cycles;
solar cycle/sunspot activity;
shifting ocean currents;
El Niño;

[1 max]

a.i.

March: $16.5 - 15.2 = \frac{{1.3}}{{16.5}} \times 100 = 7.9\,{\text{% }}$ reduction (accept 8 %);

September: $7.0 - 3.5 = \frac{{3.5}}{{7.0}} \times 100 = 50\,{\text{% }}$ reduction;

[2]

a.ii.

slight reduction in March/remains steady since 1979;
greater reduction in September/downward trend;

[2]

a.iii.

Examiners report

Most candidates correctly answered this question.

a.i.

A large number of candidates correctly answered this question. A common mistake was errors in the calculation of percentage change

a.ii.

This question was answered well by most candidates.

a.iii.

Syllabus sections

Topic 7: Climate change and energy production » 7.2 Climate change—causes and impacts

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Topic 7: Climate change and energy production

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