Geoscience Reference
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onwards. Land per capita outside Europe was also diminishing.
15
The European
population growth was part of the demographic transition taking place worldwide.
World population rose from 600 million in 1650 to 1 billion in 1820.
The shift to new fuels represented one aspect of the energy transition then in act.
It was not, however, the most important. The main technological change was the
new utilisation of fuels, that is, the techniques designed to employ in a different way
the heat of these organic sources. For about one million year, fuels had been utilized
for heating, lighting and melting metals, while work, in economic terms, that is
organized movement in order to produce commodities and services, was only
provided by humans and animals; apart from wind and water (whose mechanical
work, in any case, was not the conversion of a fuel). The only engines able to
provide work were biological machines. The introduction of machines in order to
convert heat into mechanical power was the main change in the energy system,
comparable in importance to the discovery of
re. It was only during the 18th
century, with the invention of the steam engine by Thomas Newcomen and James
Watt, that the Age of the Machines really began. The fundamental technological
obstacle that had for millennia limited the capacity of the economic systems to
perform work, was only then overcome. In 1824, the French physicist Sadi Carnot
clearly pointed out the great novelty represented by what he called the
“
à
machines
, the thermal machines.
16
In his opinion they would have replaced soon both
the force of animals and that of water and wind. This is precisely what happened
over the last two centuries. The age of machinery began with the steam engine and
such energy transition resulted in great changes in:
”
feu
the volume and trend of energy consumption;
the process of substitution of energy carriers;
the geography of energy production;
the price of energy;
the relationship energy-economy;
the relationship energy-environment.
The following sections are devoted to these changes.
1.4.2 The Volume and Trend of Energy Consumption
Energy consumption per head diminished in Europe during the 18th century, whilst
from 1800 until 2000 it rose considerably: 5.8-fold from 1800 until 2000, that is
from 23 to 134 GJ (Fig.
1.3
).
17
Since at the same time population increased 3.5
15
On the Malthusian constraints in pre-modern
energy systems: Wrigley (
1989
). I
examined the start of the energy transition in Malanima (
2012
). The path towards the modern
economy.
16
Carnot (
1824
).
17
On energy consumption in Europe, see Bartoletto (
2012
).
“
organic
”
