Presentation on theme: "Ruralisation – integrating settlements and agriculture to provide sustainability Folke Günther Dept. of Systems Ecology, Stockholm University"— Presentation transcript:
Ruralisation – integrating settlements and agriculture to provide sustainability Folke Günther Dept. of Systems Ecology, Stockholm University E-mail: Folke.Gunther@humecol.lu.seFolke.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?
Folke.Gunther@humecol.lu.se 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
Folke.Gunther@humecol.lu.se 4 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
Folke.Gunther@humecol.lu.se 5 The Hubbert Curve Found each 5 year period Maximum finding rate Ultimately found Used Will energy prices continue to be low?
Folke.Gunther@humecol.lu.se 6 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
Folke.Gunther@humecol.lu.se 7 Will energy prices continue to be low? The Big rollover Will this be our gloomy future?
Folke.Gunther@humecol.lu.se 8 The constituents of an animal (or vegetable) body: H O C N S P Na K Ca …64 PNaKCa…64 HOCNS Na K Ca …64 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?
Folke.Gunther@humecol.lu.se 9 The HEAP trap H Hampered A Accumulation E Effluent P Process
Folke.Gunther@humecol.lu.se 10 The HEAP trap Hampered Effluent Accumulation P rocess (leakage) (stored amount) J=kQ Q J J Q kQ
Folke.Gunther@humecol.lu.se 11 Linear flows Import of nutrients compensates export of produce HEAP: Leakage equals import STORAGE EXHAUSTION: P extraction horizon: about 130 years (at current energy price) Increasing energy use per unit Increasing energy price Actual extraction horizon: Unknown HEAP: Leakage equals import
Folke.Gunther@humecol.lu.se 12 Linear flows HEAP
Folke.Gunther@humecol.lu.se 13 ’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 AGRICULTUREAGRICULTURE SETTLEMENTSETTLEMENT 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
Folke.Gunther@humecol.lu.se 14 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 0,2 hectares This means that about 0,2 hectares of such agriculture can support one individual without HEAP effects
Folke.Gunther@humecol.lu.se 15 Rules for sustainability 1.You can not be dependent on storages 2.You must have a supportive function on your support system Neither of energy Nor of nutrients Solution: Energy flows Solution: 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
Folke.Gunther@humecol.lu.se 16 The eco-unit Area: 50 ha for 200 inhabitants Diversified agriculture Providing most of the human food and all of the animal fodder Functional size, pop. about 200 Plant nutriens in food are returned to agriculture Biological greywater treatment plant (wetpark) Clean water is returned to the households Orchards Private gardensNutrient reclaim Landscape diversity Predator habitat Lee – planting Biomass production Open ditches
Folke.Gunther@humecol.lu.se 17 # 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 decisions 2. 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 33 000 The periphery is inhabited by 3 000
Folke.Gunther@humecol.lu.se 18 Ruralisation – after 12 years With the given rate of change, the centre of the municipality has a population of 24 000 The periphery is inhabited by 12 000 Groups of four Eco-units Each group is inhabited by 800 people Local parks replacing the old houses
Folke.Gunther@humecol.lu.se 19 Ruralisation – after 25 years At this stage, the centre of the municipality has a population of 12 000 The periphery is inhabited by 24 000 5 600 persons Reversed ditching: Underground streams are brought up to the surface
Folke.Gunther@humecol.lu.se 20 Ruralisation – after 50 years At the end of the ruralisation process, the centre of the municipality has a population of 3 000 The periphery is inhabited by 36 000 Area with integrated agriculture – settlements. Population density closing to 500/km 2 No HEAP-trap Nutrients 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.
Folke.Gunther@humecol.lu.se 21 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 Ruralisation Unchanged city 2,000,000,000 SEK difference Very small difference: Increased human transport equals diminished food transport
Folke.Gunther@humecol.lu.se 22 Conclusions There is an immediate need for finding strategies to avoid dependence on storages of: Energy Nutrients For sustainability, these strategies must also include a supportive behaviour towards the supporting ecosystems Regarding these restrictions, the urban structure common today is unsustainable
Folke.Gunther@humecol.lu.se 23 Conclusions To avoid dependence on storages To avoid dependence on storages of: Energy Nutrients — use flows or funds — recycle This will impose restrictions on distance
Folke.Gunther@humecol.lu.se 24 Conclusions To establish a supportive behaviour towards the supporting ecosystems: Adapt to behaviours typical to mature ecosystems
Folke.Gunther@humecol.lu.se 25 Conclusions border All these strategies can be established in the border of the urban structures common today
Folke.Gunther@humecol.lu.se 26 Conclusions By advanced undulation of the borders, leading to the integration of the city with its hinterland, some obstacles to sustainability may be overcome