Distinguish between the causes of recent global warming and those of ozone depletion.

Explain the impact of global warming and ozone depletion on coastal ecosystems.

Environmental value systems may lead to different approaches to addressing the issue of global warming. Discuss which environmental value system(s) you consider to be most appropriate in the management of global warming.

Please note: although "quality of expression" marking is no longer used in exams, this question from a past syllabus may still be useful for student practice.

Gases involved:
for GW are CO2/CH4/CFCs (whereas) for OD are halogen containing gases/CFCs/NOx;

Human activities responsible:
for GW are human causes are very diverse (whereas) for OD more limited;
for GW include burning fossil fuels for transportation/agriculture/heating / rice culture / deforestation (whereas) for OD include refrigeration / spraying / cleaning electronics;

Mechanism;
for GW involves GHGs trapping more infra-red/heat (whereas) OD involves chemical breakdown of ozone molecules;
for GW involves increase in mean global temperature (whereas) OD involves more UV passing through atmosphere;

Distribution:
GW occurs globally (whereas) OD is concentrated around the poles;
OD is caused largely by MEDC activities (whereas) LEDCs make significant contribution to GW through deforestation/rice culture.

[4 max]

Please note: although "quality of expression" marking is no longer used in exams, this question from a past syllabus may still be useful for student practice.

Global Warming:
is affecting coastal ecosystem globally;
as coastal waters become warmer leads to an increase in productivity from phytoplankton;
but in some areas, waters may become too warm for locally adapted phytoplankton reducing productivity;
warmer waters hold less dissolved oxygen and may become less able to sustain larger organisms;
increase/decrease in productivity of phytoplankton will have the same impact on the entire ecosystem;
coastal ecosystems may contain coral reefs which are prone to bleaching in warmer temperature;
changing temperatures changes ecosystem characteristics and may allow invasive species to colonise an area;
sea level rise may cause coastal erosion;
change in ocean currents/El Nino patterns may bring in more nutrients increasing productivity / or the exact opposite: may deprive coastal areas from nutrient inflow thus decreasing productivity;

Ozone depletion:
may be more important in southern oceans or northern oceans around coastlines as ozone hole is greater near the poles;
Increases mutation rates in phytoplankton changing ecosystem dynamics;
ozone depletion differential reduces productivity of phytoplankton (some more than others);
reduced primary productivity has knock-on effects for entire ecosystems and may reduce population sizes of consumers and secondary productivity of ecosystem;
increased UV may cause health effects/reduce viability of marine animals e.g. young fish/shrimp larva/sea urchins living in coastal waters. 

Award [4 max] if only global warming or ozone depletion considered.

[6 max]

Please note: although "quality of expression" marking is no longer used in exams, this question from a past syllabus may still be useful for student practice.

Please note: although "quality of expression" marking is no longer used in exams, this question from a past syllabus may still be useful for student practice.

Ecocentric approaches:
promote education about global warming as a way to change human behaviour causing the problem;
promote energy efficient strategies in order to reduce production of greenhouse gases (GHG);
promote greater use of public transport / reduced flights / car sharing in order to reduce GHG production;
promote changes in diet to reduce meat consumption and thus reduce meat industry’s contribution to GHGs;
small communities, self-sufficiency / reduction of food miles, reduced consumerism - so less production GHG;

Anthropocentric approaches:
financial incentives to change behaviour such as tax credits for using renewable energy/increasing household energy efficiency;
market based solutions such as carbon trading will incentivise companies to reduce carbon emissions;
legislation in the form of taxation on high carbon emissions;
legislation by government to reduce carbon emissions / e.g. international negotiated treaties/government targets/regional targets for carbon emissions;
community based initiatives such as meat free Mondays to reduce meat consumption and therefore community carbon footprint;

Technocentric approaches:
promote adaptation to new conditions that result from global warming;
increase research and development for new fuels/renewable/nuclear energy / carbon capture technology;
invest in geoengineering solutions to reduce effect of greenhouse gases;
promote development of new technologies to reduce carbon emissions such as more fuel efficient cars/electric cars/hybrid cars. 

Award [4 max] if only one EVS is discussed.
Award [2 max] for a personal conclusion regarding which EVS is most effective in managing global warming that is justified by evidence given in the response e.g. although I would personally favour an ecocentric approach because I think this addresses the root cause of environmental degradation...;
...the technocentric approach goes a long way to conserving the environment while allowing for the continuing economic development that seems so inevitable;
Award [7 max] for responses with no personal conclusion.

[8 max]

Expression of ideas [2 max]

Many candidates often had some partial understanding of GW and OD, but often failed to make clear distinctions. The command verb posed a high difficulty so students achieved low scores for this question.

Those candidates who understood the difference between GW and OD would generally earn a couple of points for global warming, and identify one for OD. Most students will describe mostly terrestrial ecosystems. Students seemed to lack understanding on the subject since they mainly got 3-4 marks at the most on this question.

Candidates seemed to have some understanding on the characteristics of the value systems but many failed to apply them specifically to strategies to address GW. The main problem remains the reading and interpretation of the question. It seems that if the question includes "Environmental impact assessment" they explain everything they know about EIA without actually answering the question.