Figures 9(a) and 9(b) in the resource booklet provide information about the production of ethanol from sugar as a biofuel.

Explain how biofuel production can be used as a strategy to control greenhouse gas emissions in Brazil.

Figures 9(a) and 9(b) in the resource booklet provide information about the production of ethanol from sugar as a biofuel.

Outline one limitation for using biofuels as a strategy to control greenhouse gas emissions.

biofuel crops can be used to absorb carbon dioxide;
biofuels produce less greenhouse gases (when burnt) compared to fossil fuels/oil/petrol/gas;
use of biofuels is carbon neutral / carbon dioxide released during combustion is equal to the amount of carbon dioxide absorbed during plant growth (stage of biofuel production);
due to efficiency of biofuel production, further land clearance is not required, potentially protecting carbon sinks/forests;
production of biofuels may release less emissions than extraction and production of fossil fuels;
use of biofuels can reduce/replace use of fossil fuel (a non-renewable resource) / biofuels can replace use of fossil fuels in vehicles;
it can reduce the amount of carbon dioxide entering the atmosphere from storage.

[4 max]

producing biofuels can conflict with production of sufficient food supply (for growing population) / reduce land used for food production / can reduce food production/availability of food;
…leading to more food being imported / this can elevate cost of food, (particularly impacting on the poor) / cause food shortages / it could lead to famine;
production of biofuels can use limited resources eg water for irrigation;
…this can result in water shortages/insufficient water for other uses;
adoption of intensification of farming practices can lead to greater use of fertilizers and pesticide;
…this can result in greater pollution of the environment eg nutrient run-off can cause eutrophication / use of pesticides can cause death of non-target species;
increasing amounts of land are required for growing biofuel crops;
…this can result in loss of habitats for native species/loss of biodiversity/land clearance can lead to soil degradation;
biofuels can be expensive;
…therefore less likely to be used;
growing crops for biofuels usually involves monocultures that reduces diversity;
…monoculture system is less resilient / high risk of crop failure.

Only one limitation should be credited.
For [2] the limitation and its impact must be explained.
Do not accept that burning biofuels still releases carbon dioxide as net increase compared to use of fossil fuel is still reduced.
Accept any other reasonable suggestions.

[2 max]

Many candidates focused on biofuel replacing the use of fossil fuels and how it produced less pollution than gasoline and therefore achieved 2 marks. Common errors included: (i) suggesting that when biofuels are used they do not produce any greenhouse gases; (ii) stating that biofuels produced less GHGs without reference or comparison to fossil fuels; (iii) discussing the disadvantages of using biofuels even though the command term was ‘explain’ and not ‘evaluate’. Few candidates recognised that carbon dioxide is absorbed by the crops used to make fossil fuels or that its use could be considered carbon neutral.

The majority of candidates achieved at least one mark, with some good responses scoring 2 marks for this question. Common errors included stating two limitations (rather than the one specified) or not outlining the impact of the limitation given (e.g. a reduction in food production could lead to food shortage, famine or increase in food cost).