Award 1 mark for each relevant statement, 4 marks max:

• Positive feedback loops (destabilizing) amplify changes in an ecosystem 1 mark
• Feedback refers to the return of part of the output from a system as input so as to affect succeeding outputs 1 mark
• This drives the system towards a tipping point where a new equilibrium is adopted 1 mark
• This new equilibrium may be an alternative stable state / involve collapse of the original system 1 mark

Candidates may gain full credit by illustrating the principles of positive feedback by means of a diagram or well-developed example. Credit should be allowed for this

Named Food Production Systems

• 2 marks max for describing two named food production systems, e.g.:
  • Iowa corn production in mid-west USA is highly intensive, relying upon large machinery and inorganic nitrogen fertilizers
  • Rice-fish farming in China is a low-intensity system managed by human labor, with few chemical inputs

Comparison and Contrast

• Use of machinery vs human labor, dependency on fossil fuels

• Use of organic vs inorganic fertilizers, intensive energy needs of production of inorganic fertilizers/NO${_x}$ released from use of inorganic fertilizers

• Animal vs plant production, animals require more land use due to position in food chain

• Types of greenhouse gases produced, e.g. both rice and animal production produce methane

• Example given

5 marks max

- Award 4 marks max if only points of comparison or only points of contrast are addressed - Credit can be given for any points of comparison or contrast with regard to impact on climate change/release of greenhouse gases

7 marks total

Answers may include:

• understanding concepts and terminology of development (may not just be economic); mitigation and adaptation strategies; climate change; NAPA, UNFCCC and IPCC; EIAs
• breadth in addressing and linking climate change; demographic transition model; geographical factors such as location/biome; socio-economic and political factors may be related to EVS;
• examples of mitigation and adaptation strategies in at least two contrasting countries;
• balanced analysis discussing range of factors influencing a society’s choices;
• a conclusion that is consistent with, and supported by, analysis and examples given eg the combination of political system and economic development will be the primary determinant of the choice of mitigation and adaptation strategies, with countries such as USA preferring to invest in adaptation strategies involving hard infrastructure while less economically developed countries will heavily support the implementation of IPCC climate goals (mitigation) and education of the population to mitigate problems;

Marks	Level descriptor
0	The response does not reach a standard described by the descriptors below and is not relevant to the question.
1-3	The response contains:• minimal evidence of knowledge and understanding of ESS issues or concepts • fragmented knowledge statements poorly linked to the context of the question • some appropriate use of ESS terminology • no examples where required, or examples with insufficient explanation/relevance • superficial analysis that amounts to no more than a list of facts/ideas • judgments/conclusions that are vague or not supported by evidence/argument.
4-6	The response contains: • some evidence of sound knowledge and understanding of ESS issues and concepts • knowledge statements effectively linked to the context of the question • largely appropriate use of ESS terminology • some use of relevant examples where required, but with limited explanation • clear analysis that shows a degree of balance • some clear judgments/conclusions, supported by limited evidence/arguments.
7-9	The response contains: • substantial evidence of sound knowledge and understanding of ESS issues and concepts • a wide breadth of knowledge statements effectively linked with each other, and to the context of the question • consistently appropriate and precise use of ESS terminology • effective use of pertinent, well-explained examples, where required, showing some originality • thorough, well-balanced, insightful analysis • explicit judgments/conclusions that are well-supported by evidence/arguments and that include some critical reflection.