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3 Wild wheat Improved wheat Pest defence The farmer takes care of: Pest defence Competition with neighbours Seed distribution Planting Low yield (seed production with residual energy) High yield (seed production with residual energy) by the use of fossil fuels Necessary functions: Adaptation to cheap energy: Case 1: agriculture
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Ruralisation – integrating settlements and agriculture to provide sustainability
Folke Günther Dept. of Systems Ecology, Stockholm University
E-mail: [email protected]: http://etnhum.etn.lu.se/~fg/index.htm
Availabilty for gasoline energy at gas station (working time for one kWh)
Energy availability today: About ten times more than 1920
Is energy cheap?
Wild wheat
Improved wheat
Pest defence
The farmer takes care of:
Pest defence
Competition with neighbours
Competition with neighbours
Seed distribution
Seed distribution
Planting
Planting
Aquisition of nutrients
Aquisition of nutrients
Feeding fungi and micro-organism s
Soil treatm ent
Soil treatm ent
Low yield(seed production with residual energy)
High yield(seed production with residual energy)
by the use of fossil fuels
Necessary functions:
Adaptation to cheap energy: Case 1: agriculture
0
5000
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15000
20000
25000
30000
35000
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45000
House Car Food
Ener
gy u
se, k
Wh/
year
Potential for efficiencyincrease
Light car (5-7 l/100 km)
Saving potential: about 6 000 kWh/yr
The car (assuming 15 000 km/yr)
Heavy car (10-12 l/100 km)Conventional house (according to ’Byggnorm 80’)
Super-isolated house
Saving potential: about 8 000 kWh/yr
The house:
Necessary for respiration, 4000 kWh
Assumed local handling, 4000 kWh
Food management: (Energy efficiency less than 10:1)
Saving potential: about 32 000 kWh/yr(associated with vulnerability to high energy prices)
Assume: Four persons living in a house
Adaptation to cheap energy, Case 2: settlements
Will energy prices continue to be low?
This is what this workshop is about, so I will not delay on that
You all have a good insight into theese matters.
Will energy prices continue to be low?The Big rollover
Will this be our gloomy future?
However, the effects of decreased energy availability must be considered For food production, nutrient availability is essential Of the nutrients, those with limited supply are essential Biological systems solved these problems about 400 millon
years ago Cyclic flows
The constituents of an animal (or vegetable) body:HHOOCCNNSSPPNaNaKKCaCa……6464
PPNaNaKKCaCa……6464
HHOOCCNNSS
NaNaKKCaCa……6464
With gaseous phases — can be transported by the airWithout gaseous phases — must be transported as solids or liquids
More common in the Earth crust than in the body
10 times more common in the body than in the Earth crust
Why phosphorus?
Must be concentrated in the body
Linear flows — typical for western agriculture
Import of nutrients
compensates export of produce
HEAP:Leakageequalsimport
STORAGE EXHAUSTION:P extraction horizon: about 130 years (at current energy price)Increasing energy use per unitActual extraction horizon: Unknown
HEAP:Leakageequalsimport
Linear flows
HEAP
HEAP
A linear flow from sources to seaEnergy demanding and unsustainable
Fossil fuel demand
Resource depletionFossil fuel demand
Fossil fuel demand
Fossil fuel demand
Fossil fuel demand
Fossil fuel demand
Resource depletion
Resource depletion
Fossil fuel demand
Fossil fuel demand
Fossil fuel demand
’Balanced agriculture’:
-- manure is used for fodder production About 80% of the
nutrients are circulated
AGRICULTURESETTLEMENT
3-4 kg represents the phosphorus turnover of about 5 persons
About 20% is exported
This amount, 20% need to be imported
The balanced agriculture — settlement
Hence, one person is in nutrient
balance with about 0.2 hectares of
balanced agriculture
Conclusion 1
About 6 persons are in nutrient balance with 1 hectare of balanced agriculture
Given that the the agriculture provides the people with food and nutrient containing residues are returned to the agriculture
This means that about 0.2 0.2 hectareshectares of such agriculture can support one individual without HEAP effects
Rules for sustainabilityRules for sustainability
1.1. You can not be dependent on storagesYou can not be dependent on storages
2.2. You must have a supportive function You must have a supportive function on your support systemon your support system
Neither of energy Nor of nutrients
Solution: Energy flowsSolution: Recycling
Solution: Improve (not just maintain) the health of your ecosystem
Corollary: Food should be produced as close as possible to the consumer in order to diminish food system energy needs and maximise nutrient recycling capacity
The eco-unit Area: 50 ha for 200 inhabitants Diversified agriculture
Providing most of the human foodand all of the animal fodder
Functional size, pop. about 200 Plant nutriens in food arereturned to agriculture
Biological greywater treatment plant (wetpark)Clean water is returned to
the households
OrchardsPrivate gardens Nutrient reclaim
Landscape diversityPredator habitatLee – plantingBiomass production
Open ditches
Fossil fuel demand is minimized— vulnerability to fuel price changes is minimized
# The rules are: You can imagine the most ridiculous things But you have to render a statement of the effects
# A scenario is an imagination made by a scientist
The ruralisation scenario – start point
In this scenario, the following things are supposed:
4. Instead of building new houses on the places where the old ones were torn down, they decide to build eco-units in the periphery of the town.
1. The city is inhabited by decisionmakers who have the capacity to make far-sighted and strategic decisions3. Furthermore, they understand that the city is not static, but dynamic. Old houses are torne down and new are built. (The average life-time for a house is supposed to be 60 years, which gives the city a rate of change of 1,6%)
2. They have the same knowledge of limiting resources, ecology and the principles of oil depletion as you. At start point, the centre of the municipality has a population of 33 000The periphery is inhabited by 3 000
Ruralisation – after 12 years
With the given rate of change, the centre of the municipality has a population of 24 000The periphery is inhabited by 12 000
Groups of four Eco-unitsEach group is inhabited by 800 people
Local parks replacing the old houses
Ruralisation – after 25 years
At this stage, the centre of the municipality has a population of 12 000The periphery is inhabited by 24 000
5 600 persons
Reversed ditching:Underground streams are brought up to the surface
Ruralisation – after 50 years
At the end of the ruralisation process, the centre of the municipality has a population of 3 000The periphery is inhabited by 36 000
Area with integrated agriculture – settlements.Population density closing to 500/km2
No HEAP-trapNutrients are circulated
Minimal dependency of fuel storages due to: Localised food-system Use of wind, solar-power and biomass
… and the decision-makers are still there..
Many characteristics of the area (P/R-ratio, nutrient retention capacity, mutualism, biodiversity) are closing to those of mature ecosystems.
In this calculation, it is not possible to account for changes of the ’Rollover’ type. Therefore, continuous, steady changes of energy prices are assumed (In this case: 5% annual increase in price for industrial energy, and 2% for renewable energy sources)
The economy of ruralisation
Assumed annual energy cost increase:Industrial energy: 5%, Renewable energy: 2%
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5 10 15 20 25 30 35 40 45 50 55 60 65 70Years from now
WW
T m
aint
enan
ce a
nd e
nerg
y co
st, M
SEK
/yea
r
Ruralisation Unchanged town
Annual expenditure difference 2 000 MSEK
Ruralisation
Unchanged city2,000,000,000 SEK difference
Very small difference: Increased human transport equals diminished food transport
Conclusions
There is an immediate need for finding strategies to avoid dependence on storages of:
EnergyNutrients
For sustainability, these strategies must also include a supportive behaviour towards the supporting ecosystems
Regarding these restrictions, the urban structure common today is
unsustainable
Conclusions
ToTo avoid dependence o avoid dependence onn storagesstorages of:
EnergyNutrients
— use flows or funds— recycle
This will impose restrictions on distance
Conclusions
These strategies can be established in the borderborder of the urban structures common today
Conclusion
By advanced undulation of By advanced undulation of the borders, the borders, leading to the leading to the integrationintegration of the of the city with its hinterland, city with its hinterland, some obstacles to sustainability some obstacles to sustainability may be overcomemay be overcome
OK (?)
Industrial energy availability: Easy(< 100 s/kWh)
OK (?)OK
Industrial energy availability: Hard(> 500 s/kWh)
WrongRightSociety planning strategy
