Urbanisation Flashcards
how many people live in urban areas now
50%
how many people lived in urban areas in 1950
30%
in developing countries where do most people live
in rural areas
4 processes that involve the movement of people into and out of urban areas
urbanisation, suburbanisation, counter-urbanisation, urban resurgance
whats urbanisation
growth in the proportion of people living in urban areas and occurs because of rural-urban migration and natural increase . many migrants are young adults looking for jobs,schools, healthcare
in developing countries what can urbanisation result in
results in shanty towns- unplanned and often illegal settlements made out of any material available
whats suburbanisation
this is the migration of people from city centres to the outskirts of cities . as urbanisation increases city centres become overcrowded and improvements in transport links means richer people move to the suburbs , this can lead to ethnic and economic segregation
whats counter-urbanisation
movement of people out of the city into surrounding villages and rural areas . people leave the cities because of high property prices or just preference . this can lead to housing estates being built and house prices may increase meaing locals may not be able to afford prices . can change the age structure of the area
urban resurgence
movement of people back to the city centre. this may be because of lack of jobs in rural areas, new shops and services may open in the citys as people move back creating jobs and boosting economy
whats a megacity and an example
a city with a population of over 10 mill eg instabull, tokyo
how many megacities were there in 1950
2, tokyo and new york
how many megacities in 1950
2 tokyo and new york
how many megacities in 2014
28
whats a world city
a city that has political and financial influence over the whole world eg london
why does it rain more often in urban areas
- the UHI effect means more warm air rises and warm air can hold more water . and so as this warm air cools it condenses into vapour and rains this is convectional rainfall
- urban areas produce dust and pollution , these act as condensation nuclei this encourages cloud formation
sources of particulates
vehicle exhausts
burning
construction, mining, quarrying
plants and moulds
whats photochemical smog
when pollutants such as NO, SO4, hydrocarbons come into contact with sunlight the UV light causes them to breakdown into harmful chemicals
what is photochemical smog linked to
health problems, breathing difficulties , respiratory disorders and headaches
how does congestion charges reduce air pollution
people are charged if they use their vehicles in certain places at certain times . this reduces pollution by reducing road traffic , in central london emissions reduced by 15% in the first year , however some people travel around the edge of the zones to avoid charges
how does pedestrianisation reduce air pollution
vehicles are restricted from entering certain places at certain times. reducing road traffic. can lead to shops receiving fewer customers because people can only get to them on foot
how does public transport improvements reduce air pollution
bus serves can be made cheaper faster and more efficient
park and ride schemes to make it easier to access public transport
trams and light railways services which run on lines so they dont get caught in road congestion
how do other schemes for reducing traffic help reduce air pollution
in mexico city drivers are banned from using their car one weekday per week based on the last digit of the number plate however rich people just buy 2 cars.
birmingham bristol and london have council run car sharing schemes to encourage people to share cars however this can be incovenient and some worry about sharing with strangers
how does legislation reduce air pollution (uk air acts)
uk clean air acts of 1956 and 1968 introduced smoke control areas where only smokeless fuels could be burned and reduced industrial pollution by introducing tall chimneys
road vehicle regulations means cars have to pass emmisions test in their MOT
how do alternate fuel sources reduce air pollution
petrol and diesel are replaced with cleaner fuels that pollute less like
- biofuels from plants , can replace petrol and deisel but can reduce biodiversity
- liquefied petroleum gas, produced from fossil fuels has lower emmisions but service stations and cars would have to be adapted for use
-electric vehicles - run off batteries , need recharging points and producing and disposing of batteries can cause environmental issues
why is photochemical smog pollution more common in hot climate
theres more sunlight so more UV to break down pollutants into harmfull chemicals
why is infiltration low in urban areas
as urban areas are covered in impermeable surfaces
whats catchment management
a way of managing rivers and improving drainage systems by looking at the whole river catchment and the interactions between water and land. aims to minimise issues such as flooding, draught, water pollution and erosion and to improve river ecosystems