Date | November 2015 | Marks available | 4 | Reference code | 15N.2.SL.TZ0.3 |
Level | Standard Level | Paper | Paper 2 | Time zone | Time zone 0 |
Command term | Distinguish | Question number | 3 | Adapted from | N/A |
Question
Distinguish between a human carrying capacity and an ecological footprint of a population.
Explain the factors which influence the choice of energy sources in two different societies.
Evaluate the role of national and international development policies in reducing human population growth.
Markscheme
carrying capacity is defined as the maximum number of a species/“load” that can be sustainably supported by an environment;
human carrying capacity can exceed the “natural” carrying capacity through importing goods / use of technology;
the ecological footprint of a population is defined as the area of land (and water) required to support a (defined) human population at a given standard of living;
the measure takes account of the area required to provide all the resources needed by the population, and the assimilation/absorption of all wastes;
an ecological footprint may exceed the amount of land directly available to a given human population;
ecological footprints are the inverse of carrying capacity;
[4 max]
Example Data (from World Bank 2013) to help marking team:
Australia’s electricity production is mostly from fossil fuels (91 %) with 5 % from hydropower / Chile’s electricity production is 60 % from fossil fuels and 36 % from hydropower / Argentina’s electricity production is 66 % from fossil fuels and 27 % from hydropower / Almost 100 % of Mozambique’s electricity production is from hydropower / 82 % of energy produced (not just electricity) is from biomass products and waste and only about 12 % of the population has access to electricity mostly in urban centres.
Eg China and Switzerland: Switzerland’s electricity production is split between hydropower (about 60 %) and nuclear (about 40 %) with a very small percentage from fossil fuels while China’s electricity production is split between fossil fuel (about 80 %) to hydropower (about 20 %);
Availability:
location (eg coastal for tidal / offshore wind / thin crust for geothermal / high solar input for solar energy);
topography (mountains/rivers for HEP);
geology (reserves of coal/oil/gas);
eg China has vast reserves of coal;
eg China is the world’s largest producer of renewable energy;
eg Switzerland’s topography has allowed development of large hydropower system;
Economic:
high standard of living/technological development requires high capacity;
national wealth may limit choice of affordable technology/resources;
balance between economic development and environmental impacts;
China has (until recently) prioritized economic development over environmental costs;
vast coal reserves have provided China with cheap energy and allow it to be energy independent;
Political:
countries may need to respond to changing values in their own population eg (rising ecocentrism);
eg Switzerland’s political system has encouraged a low dependence on fossil fuels;
eg Switzerland’s political system has encouraged energy independence as much as possible;
international agreements (through the COP discussions) may place pressure to change energy mix;
eg China's air pollution problems have led to pressure to reduce use of coal (near cities);
Cultural:
countries may have strong historical traditions/value systems/international reputations to maintain;
historical events may influence decisions (eg countries experiencing nuclear disasters / oil embargoes);
Technological:
technological developments may make new choices available;
countries may or may not have technical expertise for certain choices;
eg China is the largest producer of photovoltaic cells in the world and this may mean increasing use of this technology within the country and not just for export;
eg Switzerland is increasingly using ground source heating for new housing developments, reducing need for oil for heating;
Future planning:
countries may need to meet international agreements or unilaterally decide to reduce emissions of greenhouse gases;
eg China has plans to reduce its dependence on fossil fuels;
eg Switzerland has put in place political guidelines to reduce per capita energy use;
[Max 4] if only one society is considered.
[6 max]
domestic and international development policies may stimulate rapid population growth by lowering mortality without significantly affecting fertility;
such policies include agricultural development / improved public health / sanitation / better service infrastructure;
but reduction in death rate can encourage fall in birth rate as families see children survive;
some analysts believe that birth rates will come down by themselves as economic welfare improves and that the population problem is therefore better solved through policies to stimulate economic growth;
education about birth control encourages family planning;
widely available contraception encourages a fall in birth rates;
parents may be dependent on their children for support in their later years and this may create an incentive to have many children;
urbanization may also be a factor in reducing crude birth rates as families less reliant on children to work the land;
policies directed towards the education of women, enabling women to have greater personal and economic independence, may be the most effective method for reducing population pressure;
international development policies stem from the Millennium development goals and have been influential in focusing national policies and directing inter-governmental aid and loans;
international population conferences (eg Cairo 1994 and Strasbourg 2004) shape strategic direction of decision making at a national level;
[8 max]
Examiners report
The candidates could generally define carrying capacity and ecological footprint correctly. A few had them round the wrong way. They did find distinguishing between the two concepts difficult, often the answers were very vague.
The candidates seem to be aware of the energy sources used in case studies of specific countries. They could state reasons for the choices fairly clearly, though often they only had one reason and they repeated the same point in a number of sentences.
Naming national development policies was not a problem for the majority of candidates, however the international policies were less clear. The stronger candidates gave detailed explanations of how these policies lead to reduced population growth over time. Weaker candidates often mentioned increased growth reasons, so going off the topic of the question asked. Many candidates gave long detailed answers about one policy, usually the one child policy in China, which ultimately only gained a few points. Candidates should read the question carefully to ensure they remain focused on the question asked.