Geoscience Reference
In-Depth Information
Many past agrarian societies were able to build up and maintain sound land-use
management which enabled them to attain high energy returns on energy inputs
(EROI), in spite of the then inevitable losses in available bio-converters.
63
How-
ever, this was not for the sake of any positive environmental externality that we
might discover now and praise them for. They did so by necessity that is, because of
their own energy poverty in available carriers and sources. Thus, there is no con-
tradiction in the lack of primary energy for economic growth in an
'
organic
economy
and the typically high energy performance attained by pre-industrial
agrarian systems, as identi
'
ed by Anthony Wrigley, Rolf Peter Sieferle, Paolo
Malanima or Paul Warde.
We can understand this, following Vaclav Smil, taking into account that under
pre-industrial conditions any
nal output had to be obtained through a set of energy
production chains that relied on
rewood burnt in highly inef
cient
replaces,
animal feed bio-converted inef
ciently into power traction and manure, vegetal and
small animal human food consumption, and a small amount of raw materials also
inef
ciently transformed into costly industrial goods, and so on.
64
With only a few
alternatives available in order to increase end-use ef
ciency,
i.e.,
through the
adoption of better converters (such as stoves instead of
replaces), these societies
had to rely on the highest primary energy output they could attain if they wanted to
achieve even a small increase in the amount or the variety of
nal consumable
goods. The main way of achieving this was to develop and maintain an ef
cient
land-use pattern. Only through the increasing integration of crop production and
livestock breeding could past organic agricultures hope to achieve even a modest
rise in their agricultural and forestry output, enabling them to diversify and enrich
both household and market economies. Herein lies possibly the most important
reason explaining why, through sound landscape management, past advanced
organic agricultures were more energy ef
cient than the majority of current agri-
cultural systems (Table
2.2
).
The improvement of past organic agricultures became a key condition for any
advance in urbanization, as can be seen when looking at cropland needed to provide
staple food for any growing city. For example, when only 20 % of agricultural
output could be sold and carried to urban centres, a city with 250,000 inhabitants
such as 1820 Vienna, required an agricultural hinterland of around 22,000 km
2
(or
nearly 88 km
2
of cropland per thousand inhabitants). Thanks to an agrarian surplus
that grew by almost 60 %, in 1910 Vienna could be supplied by 24,000 km
2
of
cropland when the city already housed two million people.
65
Feeding Paris required
a footprint of around 60,000 km
2
with a population of 660,000 in 1784, and a
similar area was needed when the population exceeded two million between 1876
and 1881, and even in 1921 when it reached three million.
66
This meant a decrease
63
Agnoletti (
2006
).
64
Smil (
1999
,
2001
).
65
Krausmann (
2013
).
66
Billen et al. (
2009
).
