Outline how a positive feedback loop can impact an ecosystem.

Compare and contrast the impact of two named food production systems on climate change.

To what extent does the development of different societies impact their choice of mitigation and adaptation strategies for climate change?

positive feedback loops (destabilizing) amplify changes in an ecosystem;
feedback refers to the return of part of the output from a system as input so as to affect succeeding outputs;
this drives the system towards a tipping point where a new equilibrium is adopted;
this new equilibrium may be an alternative stable state / involve collapse of original system;
eg increased global temperatures are melting permafrost, leading to the release of methane;
...which is a greenhouse gas and leads to further increases in global temperatures;

Note: 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 system with description; (eg Iowa corn production in mid-west USA is highly intensive, relying upon large machinery and inorganic nitrogen fertilizers)
named food production system with description; (eg rice-fish farming in China is a low-intensity system managed by human labour, with few chemical inputs)

use of machinery vs human labour, dependency on fossil fuels;
use of organic vs inorganic fertilizers, intensive energy needs of production of inorganic fertilizers/NOx 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, eg both rice and animal production produce methane;

eg case study: Rice-fish farming in Thailand [1] vs cattle farming in US [1]. Both rice and cattle produce methane, a greenhouse gas [1]. Inorganic fertilisers used in cattle farming releasing nitrogen oxides into atmosphere [1]. Rice is fertilised naturally from fish faeces so has no direct impact on climate change [1]. Cattle farming involves use of heavy machinery / fossil fuels not used in rice fish farming [1]. Rice farming produces food at lower trophic level so absorbs carbon dioxide [1].

Notes: Award [2] max for description of food production systems.
Other points of comparison or contrast may be acceptable but must be explicitly linked to climate change in order to gain credit.
Award [4] 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.

Refer to paper 2 markbands, available under “your tests”  tab > supplemental materials.

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 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;

Many candidates did well on this question and understood the principle of positive feedback. A common weakness, however, was just to describe a linear sequence of disadvantageous impacts rather than an example of actual feedback.

Many did well on this question. Common weaknesses were not addressing sufficiently specific food production systems or misunderstanding the question to be addressing impacts OF climate change, rather than impacts ON climate change.

Most were able to gain some credit on this question but frequently there was a lack of accurate distinction between mitigation and adaptation strategies.