ruralisation – integrating settlements and agriculture to provide sustainability
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Ruralisation – integrating settlements and agriculture to provide sustainability. Folke Günther. Dept. of Systems Ecology, Stockholm University. E-mail: [email protected] URL: http://etnhum.etn.lu.se/~fg/index.htm. Is energy cheap?. - PowerPoint PPT PresentationTRANSCRIPT
Ruralisation – integrating settlements and agriculture to provide sustainability
Folke Günther Dept. of Systems Ecology, Stockholm University
E-mail: [email protected]
URL: 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 m icro-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
10000
15000
20000
25000
30000
35000
40000
45000
House Car Food
Ene
rgy
use,
kW
h/ye
ar
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
The Hubbert Curve
Found each 5 year period
Maximum finding rate
Ultimately found
Used
Will energy prices continue to be low?
Different utilisation modes of remaining resources
Rule: You can not use what is not found
A: The Bush mode
B: Unprobable mode
C: Probable mode
∫’found’(x)dx ≥ ∫’used’(x)dx
Will energy prices continue to be low?The Big rollover
Will this be our gloomy future?
The constituents of an animal (or vegetable) body:
HHOOCCNNSSPPNaNaKKCaCa……6464
PPNaNaKKCaCa……6464
HHOOCCNNSS
NaNaKKCaCa……6464
With gaseous phases — can be transported by the air
Without 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?
The HEAP trap
HH ampered EE ffluent AA ccumulation P P rocess
(leakage)
(stored amount)J=kQ
QJ
JQkQ
Linear flows
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 unitIncreasing energy priceActual extraction horizon: Unknown
HEAP:Leakageequalsimport
’Balanced agriculture’:
-- manure is used for fodder production About 80% of the
nutrients are
circulated
The leakage from a normal agriculture represents about 1% of the turnover
AGRICULTURESETTLEMENT
This represent the nutrient turnover of about 6 persons
About 20% is exported
The same amount, 20% need to be imported
The balanced agriculture — settlement
Conclusion 1
About 6 persons are in nutrient balance with 1 hectare of balanced agriculture
Provided that the 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 agricultureProviding 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
Orchards
Private gardens Nutrient reclaimLandscape diversityPredator habitatLee – plantingBiomass production
Open ditches
# 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 decisions2. They have the same knowledge of limiting resources, ecology and the rules for long-term survival as you. 3. 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%)
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 70
Years from now
WW
T m
aint
enan
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nerg
y co
st, M
SE
K/y
ear
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:
Energy
Nutrients
— use flows or funds
— recycle
This will impose restrictions on distance
Conclusions
To establishTo establish a supportive behaviour a supportive behaviour towards the supporting ecosystemstowards the supporting ecosystems::
Adapt to behaviours typical to mature ecosystems
Conclusions
All these strategies can be established in the borderborder of the urban structures common today
Conclusions
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
