The social metabolism in the Anthropocene: modes of subsistence, population size, and human impact on Earth

1. Presentation at thesymposiumon “The Fate of the Earth:  The Environment and Human Well-Being”, Michigan University, April 2014  The social metabolism in the Anthropocene: modes of subsistence, population size, and human impact on Earth Marina Fischer-Kowalski Fridolin Krausmann, Irene Pallua Institute ofSocial Ecology, Vienna Alpen Adria University

2. what I will talk about • The grandsocio-metabolicregimesof human history and howtheymoldourimpact upon Earth • Population dynamics • Human affluenceasenergyaffluence • Technology asmitigatingoraggravatingimpacts? • Somebetternewsforthe 21st century | Fischer- Kowalski et al. | Michigan | 4-2014

3. Anthropocene: Humansbecoming a planetaryforce – when, and why? • By thetransitionfromhumansashunters & gathererstohumansasagriculturalists, startingsome 12000 yearsago (Kaplan et al. 2009, Ruddiman 2003)? • By theindustrialtransformation in thelatterpart of the 18th century (Crutzen & Stoermer 2000)? • By the ‚Great Accelleration‘ after World War II (Steffen et al. 2007)? • Wethinkthedividinglineistheuse of fossil fuels, startingwiththe 16th century | Fischer- Kowalski et al. | Michigan | 4-2014

4. neolithic transition fossil fueltransition sustainability transition? 1.The grandsocio-metabolicregimesin human history ? Sustainable society? Agrariansocieties activesolar energyuse – land cover change, deforestation Industrial societies fossil energyuse – change in global biogeochemicalcycles Hunters and Gatherers passive solar energy use | Fischer- Kowalski et al. | Michigan | 4-2014 Source: adapted from Sieferle et al. 2006

5. Whatmakeshumans a planetaryforce?> Itisthesize of theirimpact upon nature • This impact (orrather: theanthropogenicpressure) canbeapproximated by theclassical IPAT formula (Ehrlich 1968). • I = environmental impact (pressure) • P = size of the human population • A = affluence per capita • T = technologycoefficient per unitaffluence • But: the human population at eachpoint in time is not homogenous: eachmode of subsistence (sociometabolic regime) hasitsownprofile, extension and dynamics I = P * A * T It = (Pt1 * At1 * Tt1)+ (Pt2* At2* Tt2)+ (Pt3* At3* Tt3) | Fischer- Kowalski et al. | Michigan | 4-2014

6. Steps towardsarriving at quantitative estimates and solvingtheequation • Achieve a deeperqualitative understanding of thefunctioning of thethree sociometabolic regimesand theirdynamicsacross time • Generatefromexisting global populationestimates a plausible subdivision of populations by regimesacross time • Generate a measure of „affluence“ foreachregimeacross time. Ourchoice: useenergyaffluenceas an indicatorthatisenvironmentally relevant and canbeestimated • Describethetechnology by whichthisaffluenceisgenerated and used in a quantifyableway. Ourchoice:usecarbonemissions per unitenergy (asrelatedtoclimatechange) | Fischer- Kowalski et al. | Michigan | 4-2014

7. 1. Sociometablicregimes and theirdynamics | Fischer- Kowalski et al. | Michigan | 4-2014

8. 2. Howtoarrive at populationestimatesforhunter&gatherers and agrarianpopulation • Before 10 000 BC, thewhole human worldpopulationwerehunters and gatherers; theirpopulationgrowsslowly; at an assumed plausible growth rate of 0,036 annually, theyarrive at ± 90 millions in AD 1. The remainingworldpopulationshouldalreadybeagrarian (demographicestimate). • Sociometabolic cross-check: a) when urban centresemerge, there must be an agrarianpopulation. b) in theearlyphases, ittakesabout 98 peasantstofeed 2 urban citizens; laterthisrelationshiftsto 96.5 : 3.5. Usingthisassumption and theexistingestimates of urban population, wegenerated an independentestimate of agrarianpopulation (sociometabolic estimate). Wearrive at verysimilarnumbers. • A dominance of agrarianpopulationdriveshunter&gatherersintodecline; theybecomelargelyextinct by 1500 AD. | Fischer- Kowalski et al. | Michigan | 4-2014

9. Howtoarrive at estimatesdistinguishingbetweenagrarian and industrialpopulations • Weassume urban populationsbeyond 3-4% (in extreme cases: 10%) cannotbesustained by traditional farming • Wecandemonstrateformany countries that urban growthbeyondthis ratio isdirectlylinkedto fossil fuel (peat, coal…) use. Globally, thereis a linear relationbetween fossil fueluse and thesize of urban population. • Modern classifications of „industrial countries“ don‘treach back in history so far, and they do not captureinternaldifferences (e.g. industrializedcities and agrarianhinterland). • Solution: beyondthe traditional marginal urban population, weequate „industrialpopulation“ with urban population. | Fischer- Kowalski et al. | Michigan | 4-2014

10. UK‘s urban populationtakeoff 1500-1800 AD Index: Urban population 1500 AD = 1 | Fischer- Kowalski et al. | Michigan | 4-2014

11. Global urban population and global modern energy (fossil fuels …) use 1500 – 2000 AD | Fischer- Kowalski et al. | Michigan | 4-2014

12. Global population dynamics 10,000 BC- 2000 AD by modes of subsistence b) Rise of the industrial population (1500-2000 AD) a) Hunter gatherers and agrarian population (0-1500 AD) | Fischer- Kowalski et al. | Michigan | 4-2014

13. Global population dynamics 10,000 BC- 2000 AD by modes of subsistence c) Global shares and transitions, 10,000 BC- 2000 AD | Fischer- Kowalski et al. | Michigan | 4-2014

14. 3. As environmentally relevant and long-term comparablemeasure of „affluence“ weuseenergyaffluence (DEC/capita) • DEC containscommercialenergy (asmeasured by TPES,total primaryenergysupply) plus theamount of primaryenergyinputintotheendosomaticprocesses of humans and livestock (food and feed), in calorificunits. • More recentdatawerecompiledfrom IEA (TPES) plus biomassfrom material flowaccounts. Forhistorical time periodswerelymainly on Podobnik‘s (2011) data on coalextractionandtrade, anddevelopedestimatesforbiomassusebased upon historicallandusedataandagriculturalstatistics (harvest, livestock) aswellaspopulationstatistics (Madison 2006, Krausmann & Haberl 2002) • Wegraduallybuiltup a historicaldatabaseformany countries of theworld, controllingitforconsistency and comparability (SEC database) Fromcorrellationanalysis of morerecenttimes, wecanclaimthat DEC asmeasure of energyaffluence also verywellrepresentstheamount of materialsthatcanbeused per person. So thisindicator also representssociety‘s „biophysicalaffluence“. | Fischer- Kowalski et al. | Michigan | 4-2014

15. 3. Metabolicrates by sociometabolic regime (GJ/cap DEC = energyuse) | Fischer- Kowalski et al. | Michigan | 4-2014

16. Transitions in the share of different modes of subsistence in global energy use (DEC) | Fischer- Kowalski et al. | Michigan | 4-2014

17. Transitions in share of different modes of subsistence in global energy use (DEC) DEC consists of biomass (including all food for humans, feed for livestock and all biomass used as fuel or raw material) and modern energy carriers such as fossil fuels, nuclear energy and hydroelectric energy. Note: Time axis is not to scale for different periods: -10000 to 0: 1000 year intervals; 0-1900: 100 year intervals; 1950-2010: 10 year intervals. | Fischer- Kowalski et al. | Michigan | 4-2014

18. 4. Preliminaryconclusionsfrompopulation and affluence – whatabouttechnology? • Human impact on Earth between AD 1 and AD 1500, asderivedfrompopulationgrowth and energyaffluence, increased 4,8 fold; populationgrowthalonewouldonlyhaveaccountedfor a 2,4 foldincrease. • From 1500 AD onwards, theincreaseismuchsteeper: itmorethandoubles 1500-1800, from 1700 on itdoubles per century, from 1900 on itdoubles in 50 years, and from 1950 on ittripled in 50 years. • Didtechnology in thelongrunhelptomitigatetheimpactsfrompopulation and affluence? The answerisdisconcerting: within sociometabolic regimesitdid, but thetechnologyshiftsbetweenregimesmakethingsworse. | Fischer- Kowalski et al. | Michigan | 4-2014

19. IPAT coefficientsusedforestimates *Agrarianpopsizeestimatedfrom (known) urban centres (urban = 2%-3,5% of total) **industrialpopulationsize after 1500 AD equalto global urban population ***estimatedseparatelyforagriculture (traditional / industrial) and otherproduction | Fischer- Kowalski et al. | Michigan | 4-2014

20. IPAT: Human pressure/impact due to population numbers, affluence (energy use) and technological carbon emission intensity, AD 1 - 2010 Population increasedfrom 190 – 6800 million, thatis 36 fold. Energyaffluenceincreasedfromabout 40 GJ/personto 120 GJ/person, thatis 3 fold. Carbon intensityrosefromabout 9tC/GJ toabout 15tC/GJ, thatisalmost 2 fold. | Fischer- Kowalski et al. | Michigan | 4-2014

21. Somebetternewsforthe 21st century • Forthefirst time, itisprojectedthat human populationgrowth will decline and probably turn negative withinthis century, from 2035 or 2050 onward (Lutz, Randers, UN) • Sincetheearly 1970s, per capitaenergy and material use in matureindustrial countries stagnate (Krausmann, Wiedenhofer); theirlevelistoo high fortherest of theworldcatchingupwithit – weneedtogoforcontraction and convergence, and we will not beabletoavoidthat. • Finally, humanityhasstartedtolearnhowtocreate a goodquality of life at lowerenergy and material standards - | Fischer- Kowalski et al. | Michigan | 4-2014

22. HDI Energy Global modern energyuse and human development 1975-2005 (by countries) Yes, wecan! 2005 R2 = 0,85 – 0,90 2000 1995 1990 1985 1980 1975 source: Steinberger & Roberts 2009 | Fischer- Kowalski et al. | Michigan | 4-2014