The graph shows population change in Detroit, a city in the USA.

Describe the changes in the size of Detroit’s population between 1900 and 2015.

Using examples, explain two push factors and one pull factor that help explain counter-urbanization movements.

Using examples, discuss the varied effects of human activity on urban microclimates.

Award [1] for each of four valid statements, for example:

• Detroit’s population increases between 1900 and 1950
• the most rapid growth was between 1910 and 1930
• the city’s population has declined from its peak in 1950 until 2015
• in 2015 its population was the lowest it has been since about 1915.

There may be other valid descriptive statements.

Maximum [3] if no quantification (must quote some data from y axis).

Counter-urbanization is the movement of population away from inner urban areas to a new town, a new estate, a commuter town or a village on the edge of just beyond the city limits/rural–urban fringe.

Counter-urbanization is influenced by many push and pull factors.

Award [1] for the identification of a factor affecting counter-urbanization, and a further [1] for development, up to a maximum of [5], reserving the final [1] for an example.

Push factors include:

• the high price of urban living
• congestion in urban areas
• pollution
• lack of services
• declining employment opportunities
• social problems such as high crime rates.

Pull factors include:

• the perceived improved community relations
• better schools
• bigger houses
• cleaner environments
• space.

Accept other valid suggestions eg improvements in transport, improved ICT links enabling teleworking.

For example: High crime rates in Johannesburg [1] have led to many people leaving the inner urban areas for smaller areas/relocating [1].

For example: Perceived high quality selective educational establishments in Tonbridge, Kent [1] have resulted in increased population in-migration [1].

Do not credit both mirror statements eg poor housing/good housing used as two factors.

The effects of human activity on urban climates is varied eg urban heat islands, increased cloud cover and incidence of smog, increased instability, reduced snow cover, lower air pressure, increased tunnelling of winds, ie “the canyon effect”, decreased relative humidity and so on.

The impacts depend on a number of factors: size of city, the function of the city (industrial versus post-industrial), land-use in the city (open spaces versus industrial/retail zones), population density, vehicle density.

In some cities, negative impacts of earlier urban development have been reversed by recent developments eg the Olympic Park in London, slum clearance in Barcelona to create La Rambla or the reintroduction of the Cheong-Gye-Cheon river in Seoul. These have led to reduced temperatures, reduced wind speeds, and increased humidity. Sustainable transport strategies may reduce the number
of vehicles in city centres.

Good candidates may examine the scale of the city, improvements to a city’s climate and the nature of the settlement. Good candidates should be able to explain specific aspects of the microclimate and relate it to named human activities (building, transport systems, power generation).

Responses at band D are likely to describe a limited range (at least two) of effects of human activity on microclimates.

At band E candidates will either discuss the effects in greater range/depth/types or provide some discussion of what “varied” might mean (eg negative/positive, planned/unplanned, varied locations).

At band F expect both.

Marks should be allocated according to the markbands.

No problems.

Most understood the term counter-urbanization. Factors were correctly identified, but often not developed. Mirror points were not uncommon.

There were some good responses, focusing on heat islands, pollution and winds. Weaker candidates gave generalized accounts of pollution. There was a lot of misunderstanding of the role of pollution and CO₂ emission in the urban heat island effect. Few explicitly discussed the question.