| Date | May 2018 | Marks available | 2 | Reference code | 18M.2.SL.TZ0.1 |
| Level | Standard Level | Paper | Paper 2 | Time zone | Time zone 0 |
| Command term | Outline | Question number | 1 | Adapted from | N/A |
Question
Figure 1 shows the process of carbon capture and storage (CCS) that can be used to manage climate change. Carbon dioxide (CO2) is pumped into three different underground locations, where it is stored.
Flow 1 pumps CO2 into an underground saline reservoir.
Flow 2 pumps CO2 into an oil reservoir; CO2 replaces oil; oil is produced.
Flow 3 pumps CO2 into a coal seam; CO2 replaces methane (CH4); methane is produced.
Figure 1: Carbon capture and storage flow chart
[Source: Adapted from http://www.wri.org/resources/charts-graphs/carbon-capture-sequestration-flow-chart.
Licensed under CC BY 4.0 International https://creativecommons.org/licenses/by/4.0/]
Outline the evidence that CO2 acts as a greenhouse gas.
State a greenhouse gas other than CO2.
Outline how the mitigation strategy shown in Figure 1 is different to an adaptation strategy for managing climate change.
Identify two mitigation strategies to manage climate change, other than carbon capture and storage.
Outline how Flows 1 and 2 shown in Figure 1 may contribute to the capture and storage of atmospheric carbon.
Markscheme
CO2 absorbs (outgoing) longwave/IR radiation/heat elevating global temperatures.
Accept references to climate / CO2 data as causal link, eg increase in global CO2 levels correlate with rises in global temperatures.
methane / water vapour / nitrous oxide / tropospheric ozone / CFCs / HCFCs / HFCs.
NB if candidate names more than one gas only the first one should be assessed (even if the first is wrong and a later one is correct).
the mitigation strategy reduces the cause of climate change by removing CO2/greenhouse gas from atmosphere;
whereas an adaptation strategy reduces negative/maximises positive impacts of climate change / addresses impacts rather than causes of climate change.
Responses may involve giving examples of either mitigation or adaptation strategies, but to gain the [2 max] they must include the characteristic/distinguishing feature of both mitigation and adaptation (ie “reducing cause” and “addressing impacts”, respectively).
reducing energy/fossil fuel consumption through carbon tax/cap & trade;
reducing emissions of NOx/methane/through catalytic converters/regulations;
alternative energy sources;
geoengineering;
fertilizing oceans;
afforestation/biomass production.
Award [1] for each correct answer that will reduce emission/concentration of GHGs in atmosphere, up to [2 max].
(both) flows remove CO2 released by smokestacks/power plants/fossil fuel combustion / store waste CO2 underground/beneath impermeable rock/in saline/oil reservoirs;
however, Flow 2 is associated with extraction of fossil fuels that will release more CO2 (on combustion).
Award [1] for each correct answer, up to [2 max].
Examiners report
Unfortunately, many candidates interpreted this question as being more complex than it was, searching for evidence within the data on CCS, rather than simply stating an example of evidence required.
Vast majority of candidates were able to identify another valid greenhouse gas.
Probably around half the candidates had a tentative grasp of the distinction between mitigation and adaptation strategies, though not always sufficiently explicit for full credit. There was a significant proportion of candidates erroneously suggesting the difference lay in the fact that adaptation was about changes in lifestyle while mitigation was about technology … whereas both strategies can be addressed through either lifestyle or technological changes.
Great majority of candidates could identify a couple of valid mitigation strategies.
The majority were able to identify that both these flows trapped CO2 underground that would otherwise enter the atmosphere. A minority recognised that Flow 2 was more limited in this respect since it led to the generation of oil that on combustion would release further CO2.
