| Date | May 2021 | Marks available | 1 | Reference code | 21M.2.SL.TZ0.3 |
| Level | Standard Level | Paper | Paper 2 | Time zone | Time zone 0 |
| Command term | State | Question number | 3 | Adapted from | N/A |
Question
Figure 3: Mean ozone hole area between 1979 and 2016
[Source: NASA Ozone Watch.]
State where the ozone hole referred to in Figure 3 is located.
Describe the changes in mean ozone hole area between 1979 and 2016.
Identify one possible reason for the changes shown during the 1980s.
Explain how the data in Figure 3 can be used in judging the success of the Montreal Protocol in addressing ozone depletion.
Markscheme
in the (lower) stratosphere / over the poles / above the Antarctic/Arctic / at higher latitudes / Australia/NZ;
rapid increase during the 1980s/up to 1990s/ from 1979–87;
reaches maximum in late 1990s; relative stable during late1990s;
fluctuating from 2000 onwards;
possibly declining in late 2000s/from 2014;
Be prepared to give a little leeway in precise years for changes in trends, but some reference to their timing is required.
increasing use of/disposal of refrigerants containing CFCs;
increasing use of CFCs in aerosols;
increasing release of NOx from fossil fuel combustion; increasing use of methyl bromides as pesticides;
Responses should identify the ODS and its use for full credit.
Montreal Protocol was introduced in 1987/graph covers period before and after introduction of Montreal Protocol;
it introduced a ban on the use of CFCs / led to use of alternative HCFs/HFs;
rate of ozone destruction/growth of the ozone hole slows down/stops soon after this date;
suggesting it had some success/favourable impact on ozone depletion;
however, there is little evidence of ozone levels being restored to earlier levels / hole disappearing;
possibly some evidence in last few years/2014–2016 on graph of ozone hole reducing/ozone being restored;
the stabilisation/limited decline in ozone hole may suggest black market sale of ODSs (limited success);
continued impact of long-lasting ODSs (CFCs/HCFs) delay final judgement;
Examiners report
Most were able to identify either the geographic or atmospheric location of the ozone hole.
Many struggled to describe general trends of change in the data of this graph, either opting for just an 'overall increase' or describing year by year changes.
Few accurately identified the possible causes of this change in the ozone hole.
Many were able to gain some credit for their responses to this question, but few recognised the reduction in RATE of increase in the ozone hole which was the major achievement of the Montreal Protocol and the persistence of CFCs preventing any substantial decline.
