Describe the role of primary producers in ecosystems.

Explain the potential impact of ocean acidification on environmental systems and societies.

To what extent do anthropocentric value systems dominate the international efforts to address climate change?

producers are plants that convert light energy into chemical energy by photosynthesis;
photosynthesis/primary producers convert carbon dioxide and water into glucose/sugar and oxygen;
this conversion/glucose forms the raw material of biomass/the basis of food chains;
producers (thereby) provide food for consumers/energy in a form that can be passed along food chains;
the production of oxygen by producers is vital for the majority of ecosystems;
the absorption of CO₂ maintains a balance of CO₂ in atmosphere/reduces global warming;
primary producers may alternatively generate biomass through chemosynthesis;
chemosynthetic bacteria use chemical energy to produce food without using sunlight;
plants may also provide other resources/services for ecosystem eg habitats/soil conservation/cycling of matter;

Award [1] for each correct role described, up to [4 max].

ocean acidification is caused by increased CO₂ levels in atmosphere leading to more CO₂ absorbed into ocean;
the CO₂ reacts with the water forming an acid (carbonic acid)/decreasing the pH/changing pH from about 8.2 to 8.1;
macro-algae/seagrasses may benefit from higher CO₂ conditions in the ocean;
some organisms are adapted to a narrow pH range/very sensitive to pH changes;
low pH/reduces ability of shelled organisms to maintain their shells/reduces reproductive ability in fish/shellfish;
producers eg phytoplankton/corals in ocean environments can be particularly sensitive to low pH;
corals are more prone to bleaching/less able to recover from damage in acidified water;
reduction in producers reduces the resilience of an ecosystem/impacts entire food webs/is a potential tipping point for marine systems/reduces biodiversity;
collapse of a natural ecosystem may lead to collapse of fisheries/collapse of aquaculture (eg oysters)/overfishing of diminishing fish populations;
loss of fisheries can lead to limited food supply for indigenous communities/need to import food;
decline in fishing/aquaculture would result in reduced employment/socio-economic hardship;
coral reefs support economically valuable ecotourism that may be lost/decline;
loss of corals will bring an aesthetic loss/infringe biorights of organisms;

Do not credit responses that mistakenly address acid deposition.
Award 2 max for describing process of acidification.
Award 5 max if impacts are limited only to ecosystems or only to societies.

Award [1] for each correct explanation, up to [7 max].

The following guide for using the markbands suggests certain features that may be offered in responses. The five headings coincide with the criteria given in each of the markbands (although “ESS terminology” has been conflated with “Understanding concepts”). This guide simply provides some possible inclusions and should not be seen as requisite or comprehensive. It outlines the kind of elements to look for when deciding on the appropriate markband and the specific mark within that band.

Answers may include:

• understanding concepts and terminology of anthropocentric/technocentric/ecocentric values, sustainability, climate change, global warming, C emission, international NGOs/GOs, international agreements/protocols, mitigation, adaptation, MEDCs v LEDCs etc
• breadth in addressing and linking international strategies addressing climate change relevant EVS eg anthropocentric with environmental regulations, carbon tax, international agreements/protocols  eg technocentric with carbon storage, alternative energies, vaccination programmes, desalinisation, flood defences, eg ecocentric with afforestation, energy reduction, reduced consumerism, more sustainable/localised agricultural systems etc
• examples of international strategies eg Kyoto protocol, Paris Agreement, UN Convention on Climate Change, carbon trading, REDD (Reduced Emissions from Deforestation & Degradation), and range of strategies employed internationally eg desalinisation in areas of water scarcity, flood defences in coastal regions, shifting cultivation to more appropriate latitudes, Greenpeace global aim for 100% renewable energy etc
• balanced analysis of the extent to which international efforts are dominated by anthropocentric values, acknowledging relevant counter-arguments/alternative viewpoints
• a conclusion that is consistent with, and supported by, analysis and examples given eg “All value systems have a valuable contribution in addressing climate change, but anthropocentric values are particularly critical in achieving a more concerted effort internationally in that technological solutions are often limited to MEDCs and ecocentric solutions tend to be very localised.” NB This is only an example of a possible conclusion. Candidates’ conclusions do not have to agree.

Please refer to paper 2 markbands, available under the "your tests" tab > supplemental materials

Q4 was the most popular choice in Section B. Great majority were able to identify a couple of aspects of the role of primary producers but few went on to gain full credit.

There were some excellently detailed answers in response to this question, though a great number confused ocean acidification with acid precipitation which have very different causes and impacts. Similarly, many mistakenly addressed contamination of food sources, bioaccumulation etc.

Again there were some very impressive responses that correctly characterised the anthropocentric position and their role in many named international agreements developing a clear argument in contrast to other environmental value systems. A good deal of responses, however, portrayed a rather distorted version of anthropocentrism more along the lines of cornucopian values or climate change sceptics, so the argument became unbalanced or confused.