Civil Engineering Reference
In-Depth Information
per person in the country being considered, and national per capita biocapacities
for our featured six countries are shown in the fifth column of
Table 13.3.
Apart
from Norway, all the countries in
Table 13.3
exceed their own biocapacity. As the
final column shows, most countries have a negative ecological surplus - in other
words, they have an ecological deficit. This ecological deficit measures the amount
by which a country's footprint exceeds its biocapacity. Only about a third of the 150
countries for which a footprint has been calculated show a ecological surplus - they
have some ecological reserve as not all their national (biological) capacity is used
for consumption, or absorption of waste, by their own populations. This ecological
reserve, however, does not necessarily remain untouched, as it may be used by other
countries through production for export.
Most countries' biocapacity (determined by the resources available within their
borders) is smaller than their ecological footprint (which is based on the resources
that they actually consume). You might think that this is particularly the case in
high-income countries, and certainly the United States and most nations in Western
Europe have significant ecological deficits. However, some developed countries, such
as Norway (as
Table 13.3
shows), Canada and Australia, have ecological surpluses
because they have relatively abundant resources. Conversely, many countries in the
developing world have ecological deficits, because they are resource poor or because
they have large populations relative to their resource base.
This paints rather a daunting picture, as the only way to reduce a nation's
ecological footprint, or more importantly the global ecological footprint, is
if populations become smaller, or if we can find a way to reduce the average
consumption per person and increase resource efficiency through changes in
technology. The latter could be achieved in part by using fewer fossil fuels to reduce
carbon emissions and becoming more reliant on energy from renewable sources.
THE ECOLOGICAL FOOTPRINT AND CONSTRUCTION
The scale of the demands made on the natural environment is easily exemplified
by construction, as the sector (on the broad definition) consumes resources and
generates waste on a scale that completely dwarfs other sectors of the economy.
To begin with, it is the environment that provides the land on which buildings and
infrastructure are located. Subsequently, it is the environment that supplies many of
the resources that are used to make building material products. Finally, it is also
the environment that is ultimately responsible for assimilating and processing the
waste that arises from the various phases of a property's life, from construction
through to demolition. The scale of the problem was discussed in
Chapter 11
. There
we considered the resource intensive nature of construction inputs and outputs, and
discussed the problems of an industry that produces 3 tonnes of construction waste
for each man, woman and child in the UK
Changes in the ways that property is designed and used could have a significant
impact on the scale of the ecological footprint. At present, a large part of the
ecological footprint is generated through energy usage, as carbon emissions make
up about half of the total footprint. These could be reduced to zero by designing
buildings to harness renewable sources, so-called carbon-neutral solutions that rely
