Geography Reference
In-Depth Information
64
Transport System Changes
Our modern urban and economic progress has been built on the various transporta-
tion and communication improvements that allow us to move people and goods
quickly and relatively cheaply between places. Since the Industrial Revolution
these new transport systems have depended largely upon various fossil fuels, from
coal in steam engines to various types of oil or gas in cars, trains, planes and ships.
Although there are increasing worries about the increase in pollution at high alti-
tudes from the growing number of aeroplanes, and at sea from the heavy bunker
fuels used by ships, it is the emissions from the growing numbers of car and com-
mercial vehicles over the past 20 years that provides the major concern for urban
areas, as well as increasing congestion in cities. As Fig. 5.6 in Chap. 5 has shown,
transport is estimated to be the third largest urban source of greenhouse gas emis-
sions (OICA
2012
), while in the European Union vehicles are estimated to account
for 12 % of its carbon dioxide emissions (EU-clima
2013
). Much of this output
occurs in cities, with the daily journey-to-work a major generator of emissions,
given that it is so concentrated in time, with peaks to and from work, and in many
cities with a focus on downtown, although this is changing as large metropolitan
areas become polycentric and employment increases in suburban areas. However
there are major variations in urban areas in the level of these emissions. One is
related to the extent to which transport other than cars is used to get to work. The
Green Index study (EIU
2012
) revealed that 63 % of the population in European
cities in the study used green transport to get to work (public transport systems or
bicycles), although with a huge range—from 90 to 33 % in the sample cities—while
in North American cities the average is only 13 %, so pollution levels from vehicles
are far higher.
An important reason for the differences between cities of the world lies in the
relation between urban densities and pollution levels. Figure
6.1
shows that the
sprawling southern cities in the U.S.A., such as Atlanta and Houston, that are so
dependent upon automobiles for transportation, have per capita emissions of carbon
dioxide that are over four times the rate of cities such as London and Barcelona,
and well over twelve times those of Hong Kong and Mumbai. This has led many to
argue that increasing urban density, such as the Smart Growth approaches discussed
in Chap. 2, will make a major contribution to the reduction of carbon emissions.
However the very size and location of the existing building stock means that it is
unlikely that the existing patterns of density can change significantly in the foresee-
able future. So other solutions are being found to reduce vehicle use, which in turn
reduces emissions and the amount of fossil fuel used, thereby increasing sustain-
ability levels.
6.4.1
Reducing Car Use
Four main approaches have been used to decrease the use and number of cars in
cities in order to reduce pollution from emissions, congestion and accidents. The
