Ruralisation – integrating settlements and agriculture to provide sustainability

Folke Günther Dept. of Systems Ecology, Stockholm University

E-mail: Folke.Gunther@humecol.lu.se

URL: http://etnhum.etn.lu.se/~fg/index.htm

Folke.Gunther@humecol.lu.se 2

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

Seed distribution

Planting

Aquisition of nutrients

Feeding fungi and m icro-organism s

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

House Car Food

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

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

HHampered

AAccumulation EEffluent

PProcess

The HEAP trap

HH ampered EE ffluent AA ccumulation P P rocess

(leakage)

(stored amount)J=kQ

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

Linear flows

’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

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

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%

5 10 15 20 25 30 35 40 45 50 55 60 65 70

Years from now

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

Ruralisation – integrating settlements and agriculture to provide sustainability

energy cheap

cheap energy

gasoline energy

energy flowssolution

food system energy

high energy pricesassume

nutrient recycling

nutrient balance

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