Environmental Engineering Reference
In-Depth Information
The great concentrations of humanity in urban areas (increasingly in megacities),
the afl uent lives of some 20% of the world's population, and the rising economic
aspirations of billions of inhabitants of low-income countries have been made pos-
sible by unprecedented levels of energy consumption. Although the extraction and
conversion of fossil fuels, the dominant sources of primary energy supply, proceeds
with high power densities, those processes still make signii cant land claims. My
detailed estimate for the United States in the early 2000s showed that the extraction
of fossil fuels claimed less than 500 km 2 , and so did the mostly coal-i red thermal
electricity generation; fuel processing (including the rei ning of imported crude oil)
needed about 2,000 km 2 (Smil 2008).
Areas entirely stripped of vegetation, built up, or paved are thus fairly small, and
much larger claims are made by pipeline and transmission rights-of-way: the former
added up to less than 12,000 km 2 , the latter had reached about 9,000 km 2 . Those
rights-of-way preclude many land uses (including regrowth of natural vegetation)
but allow for harvests ranging from crop i elds to grazing land and Christmas tree
plantations. By the year 2000 the United States also had an outstanding land debt
of some 4,000 km 2 of unreclaimed coal mine land (some of it with natural regrowth).
The aggregate of land claimed by the U.S. fossil fuel energy system was thus about
25,000 km 2 (no more than 0.25% of the country's territory, or an equivalent of
Vermont), and net additions during the i rst decade of the twenty-i rst century were
less than 1,000 km 2 a year. Estimating the worldwide extent of land claimed by
modern energy infrastructures is much more uncertain.
My calculations for the beginning of the twenty-i rst century (generally based on
fairly liberal assumptions) resulted in no more than 300,000 km 2 , or an Italy-sized
area occupying roughly 0.25% of the Earth's ice-free land (Smil 2008). But less than
10% of that total was claimed by extraction and processing of fossil fuels and by
the generation of thermal electricity generation, and more than half of the total was
due to water reservoirs for hydroelectricity generation. But attributing all of that
water-covered area to energy infrastructure is arguable because many reservoirs
have multiple uses, supplying water for irrigation, industries, and cities and provid-
ing opportunities for recreation. A rough proportional attribution of reservoirs'
surfaces would cut the total claim of global energy infrastructures to less than
200,000 km 2 , and if all the land occupied by reservoirs and transmission rights-of-
way was left aside (the latter choice justii ed by the fact that the land can be used
for crops or grazing), then the overall land claim would be more than 75,000 km 2 ,
roughly the area of Ireland.
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