Cities and Sustainability
After spending tens of thousands of years living in small settlements, humans have entered an urban stage of evolution.
That concentration of people gives rise to some of the world's greatest
problems, such as air and water pollution, poverty-stricken slums and epidemics
of violence and illness.
In less than a human lifespan, the face of Earth has been
transformed. In 1950, only 29% of people lived in cities. Today that figure is
50.5% and is expected to reach 70% by 2050. At the end of the 20th century,
humans lived in enlarging cities with populations in the millions; their carbon dioxide emissions
are greater than the capacity of all the world’s forests to process the gas.
Cities consumed two-thirds of the
total energy used and emitted more
than 70% of the energy-related carbon dioxide emissions. City states are
depleting these resources at an alarming rate – fish stocks are depleted; soils
are depleted, washed or blown away; fresh water supplies are marginal, depleted
or contaminated; the air is polluted and ozone depletion combined with global
warming from increased greenhouse gases threatens progressive and erratic
climate changes. Climate changes threaten agriculture, as we know it.
William Rees, an economist at the University of British
Columbia takes and ecological approach to economics. He is concerned that cities
are growing too large to be sustainable. Cities are centers of consumption and depend on the surrounding
environment to supply energy, food and to accept and disperse waste. Rees has
measured the ecological footprint of cities and his results are not encouraging.
One city person requires at least five square hectares of high-quality land to
support him or her. The 500,000 people living in the city of Vancouver on 11,400
hectares of land actually require the output of 2.3 million hectares of land.
The real capital is not money but air,
water, food and other resources.
Some scientists have imagined major disruptions of
city-states with civil disobedience and armed conflicts arising from the
competition for scarce resources. Solutions are available but are improbable,
given our basic tendencies. A sane,
rational city-state would limit its growth; limit its pollution and progress
toward food, water and air sustainability. If all long-distance supplies were
blocked could the citizens of a city continue to live comfortable, healthy
lives? One criterion of a sane city
would be self-sufficiency. To make cities more livable and less polluted, car
use would be reduced to less than half of current levels and car-free zones
would restore healthier living conditions for many citizens.
For many urban dwellers, advanced electronic networking
would reduce the need for commuting and long-distance travel would be considered
a luxury and rationed. The need to transport food and goods would be reduced by
increased local production. The transportation of goods would be streamlined
into centrally controlled supply lines that achieve maximal efficiency. We could
advance toward intelligent distribution systems such as large pneumatic or
electromagnetic tubes that send containers between city centers at high speed
with minimal pollution. It is absurd to have goods distributed in trucks, in
traffic, chaotically with no cost effective distribution plan. Food can be grown and processed within a city by returning some of the
land area to market gardens and intensive greenhouse technology.
Cities are governed by elected politicians who have a range of abilities and
limited knowledge of the environment and Human Nature. Urban governments exist to provide services to citizens. Usually, planning is
motivated to increase populations by expanding developments that are destructive
of the surrounding environments. Cities are cancers that overwhelm their host. In 2016 the city of Vancouver has a “housing crisis.” The demand for living
space has exceeded supply, the price of real estate is rising and educated young
people entering the workforce cannot afford to live in the city. Planners are
suggesting that green space around the city should be developed to provide
rental housing. No one suggests that there must be no further city growth
and increasing the population is not desirable nor feasible.
Cities are so enmeshed in their surrounding regions that it no longer
makes sense for them to be the sole focus of sustainable planning. Satellite
images reveal patchworks of communities, industrial zones, farmland and natural
ecosystems threaded by a web of transport links. For people and nature to
thrive, the arrangement of land systems and water across the urban region must be managed holistically. Essential are experts in ecosystem and landscape
ecology, water quantity and quality, agricultural soil quality and productivity,
economics, transportation infrastructure engineering and community development.
The Science journal Nature published a special edition of Cities. By
2030, 1.1 billion more people will live on Earth — bringing the total to about
8.5 billion. Most of them will arrive in dense Asian and African cities,
exacerbating pollution and resource shortages. Urban expansion denigrates
the environment with loss of natural vegetation, agricultural land, clean
water , jobs, housing, transport and healthy communities. Rapidly growing cities
such as Kano, Niamey, Sikasso and Bobo-Dioulasso in sub-Saharan West Africa are
already converting woodlands into irrigated farmland to feed their rising