A discourse on habitability: The Anthropocene as ecological dyad

The Holocene, as depicted in Figure 1 below, is formally the current geological epoch and represents the previous ∼11,500 calendar years to present. During the Holocene, environmental change occurred naturally and Earth’s regulatory capacity maintained the conditions that enabled human development. Regular temperatures, freshwater availability and biogeochemical flows all stayed predominately in a narrow range. Now, in the primeval stages of the Anthropocene, human activities have reached a level that could damage the systems that kept the Earth in the desirable Holocene state (Steffen, et. al., 2004). Remarkably, although the climate of the Holocene sustained the growth and development of modern society, there were significant rapid climate change (RCC) events during this epoch that had devastating cultural impacts. These Holocene events provide the most recent chronological points of reference for natural climate variability, and underscore the risks of mounting anthropogenic influences on the natural state of the Earth System. As we try to anticipate the potential future impacts of industrialized and modern economic growth on the natural variability that is inherent the climate system, we can refer to the following climate related events that occurred during the Holocene.

Figure 1

Figure 1. Holocene Temperature Variations. Rohde, R.A. (2006). Temperature proxies are found in Appendix A.1 below.

Mayewski, et. al. (2004), point to three rapid climate change events that occurred during the Holocene that demonstrate how even advanced cultures and societies can be destroyed by an inability or unwillingness to respond to the impacts of environmental and climate change. The short lived 1200-1000 cal. yr. B.P. RCC event coincided with the drought related collapse of the Mayan civilization and was accompanied by the loss of several million lives (Hodell et. al., 2001; Gill, 2000), while the collapse of Greenland’s Norse colonies at ∼600 cal. yr. B.P. (Buckland, et. al., 1996) coincides with a period of polar cooling that is minor by glacial standards. Even the less extensive event from 4200 to 3800 cal. yr. BP coincided with major low-latitude drought and the collapse of the Akkadian Empire (deMenocal, et. al., 2000a)(p. 252).

The background climate of the Holocene contained enough inherent variability to contribute to the destruction of civilizations and empires that were extremely advanced for their respective eras. This background variability included negligible forcing roles for carbon dioxide (CO2) and methane (CH4), and few large shifts in greenhouse gases occurred during the pre- anthropogenic Holocene. Notable exceptions were the CH4 depression at 8200 cal. yr. B.P. and the CO2 decline at 1200 cal. yr. B.P., and these changes appear to have been more the result than the cause of the RCCs (Mayewski, et. al., 2004, p. 252). The biosphere now contains ∼250 years of accumulated industrialized anthropogenic forcings that have become embedded in the biotic processes of the planet. Among these forcings are CO2 and CH4 levels not seen during the geologically brief span of time in which human societies have relied upon periods of relative climate stability in order to survive and thrive. With the exception of the major Holocene events noted above, local changes in the ability of ecosystems to support social systems and resilience remained so high that in many respects, nature could be seen as fairly stable. Change was buffered by resilience, and humanity progressed in unprecedented ways (Folke, Colding & Berkes, 2003, p. 382).

The Anthropocene Primeval

The advent of the Anthropocene is generally considered to have begun in Great Britain in the 1700s, or the thermo-industrial revolution of nineteenth century Western civilization (Grinevald, 1999), and marked the end of agriculture as the most dominant human activity. It also set the species on a far different trajectory from the one established during most of the Holocene. This industrialization was made possible through the discovery and exploitation of energy-rich, dense and easily transportable fossil fuels (Steffen, et. al., 2007). Figure 2 below illustrates the trajectory of temperature anomalies that correlate with hydrocarbon fueled, industrialized growth. This growth has altered in measurable ways the various biological, physical and chemical processes of the natural environment (Crutzen, 2002), and these impacts, or anthropogenic perturbations, have accelerated and intensified to levels never before experienced by the human species.

Figure 2

Figure 2. Reconstructed Temperature: Expansion of the Last 1000 Years. Rohde, R.A. (2006), Reconstructions found in Appendix A.2 below.

Presently, the global scale forcing mechanisms of human population growth, carbon based economic development, energy production and consumption and climate change far exceed in both rate and magnitude, the forcings evident at the most recent global scale state shift. Further, biological ‘states’ are neither steady nor in equilibrium; rather they are characterized by a defined range of deviations from a mean condition over a prescribed period of time. Industrialized human behavior – specifically the alterations to the global energy budget due to the burning of fossil fuels – has increased atmospheric CO2 concentrations by approximately 35% with respect to preindustrial levels, with consequent climatic disruptions that include a higher rate of global warming than occurred at the last global scale state shift of biotic change – extinctions, altered diversity patterns and new community compositions which occurred ∼12,900 yr B.P. (Barnosky, et. al., 2012, p. 53).

As societies and cultures determine their respective levels of habitability through this next stage – the Anthropocene Resilient – of our current geological epoch; private and public discourse must be based on a dyadic reciprocity that views future habitat construction as being fully integrated with and dependent upon the rapidly changing Earth System. Anthropogenic resilience achieved through biomimetic literacy and dialogue is a crucial first step toward understanding the daunting and complex challenges of current and future habitability. Most importantly, this discourse should support our ability to access our truly unprecedented levels of collective adaptive capacity to respond to these challenges with experiential knowledge, technological expertise and innovative collaboration.

The resonant and persistent qualities of this dialogue will be as fateful to our cultures as the lack of responsiveness to RCC events was to the inhabitants of the Holocene. Should we fail to turn these words into action, we will have squandered an abundance of opportunities to manage our habitats in ways that may well be within our collective means to respond.

References

  1. Barnosky, A.D., Hadly, E.A., Bascompte, J., Berlow, E.L., … Smith, A.B. (2012). Approaching a state shift in Earth’s biosphere. Nature, 486(7401), 52-58.
  2. Buckland, P.C., Amorosi, T., Barlow, L.K., Dugmore, A.J. … Skidmore, P. (1996). Bioarchaeological and climatological evidence for the fate of Norse farmers in medieval Greenland. Antiquity, 70(267), 88-89.
  3. Crutzen, P.J. (2002). Geology of mankind: the Anthropocene. Nature, 415-423.
  4. deMenocal, P., Ortiz, J., Guilderson, T., Adkins, J., Sarnthein, M., Baker, L. & Yarusinsky, M. (2000a). Abrupt onset and termination of the African humid period: rapid climate responses to gradual insolation forcing. Quaternary Science Reviews, 19, 347-361.
  5. Folke, C., Colding, J. & Berkes, F. (2003). Synthesis: building resilience and adaptive capacity in social-ecological systems, 352-387. In Berkes, F., Colding, J. & Folke, C., Eds. (2003). Navigating social-ecological systems. Cambridge, UK: Cambridge University Press.
  6. Gill, R.B. (2000). The Great Maya Droughts: Water, Life, and Death. University of New Mexico Press, Albuquerque.
  7. Grinevald, J. (1990). L’effet de serre de la Biosphère: De la révolution thermo-industrielle à l’écologie globale. Stratégies énergétiques, Biosphère et Societé, 1, 9-34.
  8. Hodell, D.A., Brenner, M., Curtis, J.H., Guilderson, T. (2001). Solar forcing of drought frequency in the Maya Lowlands. Science, 292, 1367-1370.
  9. 9. Mayewski, P.A., Rohling, E.E., Stager, J.C., Karlén, W., … Steig, E.J. (2004). Holocene climate variability. Quaternary Research, 62, 243-255.
  10. 10. Steffen, W., Sanderson, A., Tyson, P., Jäger, J. … Wasson, R.J. (2004). Global change and the Earth system: A planet under pressure. Berlin, DE: Springer.
  11. 11. Steffen, W., Crutzen, P.J. & McNeill, J.R. (2007). The Anthropocene: Are humans now overwhelming the great forces of nature? AMBIO: A Journal of the Human Environment, 36(8), 614-621.

APPENDIX A.1

Rohde, R.A. (2006) Holocene Temperature Variation Proxies.

  1. (dark blue) Sediment core ODP 658, interpreted sea surface temperature, Eastern Tropical Atlantic: Zhao, M., N.A.S. Beveridge, N.J. Shackleton, M. Sarnthein, and G. Eglinton (1995). “Molecular stratigraphy of cores off northwest Africa: Sea surface temperature history over the last 80 ka”. Paleoceanography 10 (3): 661-675.
  2. (blue) Vostok ice core, interpreted paleotemperature, Central Antarctica: [abstract] [DOI] Petit J.R., Jouzel J., Raynaud D., Barkov N.I., Barnola J.M., Basile I., Bender M., Chappellaz J., Davis J., Delaygue G., Delmotte M., Kotlyakov V.M., Legrand M., Lipenkov V., Lorius C., Pépin L., Ritz C., Saltzman E., Stievenard M. (1999). “Climate and Atmospheric History of the Past 420,000 years from the Vostok Ice Core, Antarctica”. Nature 399: 429-436.
  3. (light blue) GISP2 ice core, interpreted paleotemperature, Greenland: [abstract] [DOI] Alley, R.B. (2000). “The Younger Dryas cold interval as viewed from central Greenland”. Quaternary Science Reviews 19: 213-226.
  4. (green) Kilimanjaro ice core, δ18O, Eastern Central Africa: Thompson, L.G., E. Mosley- Thompson, M.E. Davis, K.A. Henderson, H.H. Brecher, V.S. Zagorodnov, T.A. Mashiotta, P.-N. Lin, V.N. Mikhalenko, D.R. Hardy, and J. Beer (2002). “Kilimanjaro Ice Core Records: Evidence of Holocene Climate Change in Tropical 
Africa”. Science 298 (5593): 589-593.
  5. (yellow) Sediment core PL07-39PC, interpreted sea surface temperature, North 
Atlantic: [abstract] [DOI] Lea, D.W., D.K. Pak, L.C. Peterson, and K.A. Hughen (2003). “Synchroneity of tropical and high-latitude Atlantic temperatures over the last glacial termination”.Science 301 (5638): 1361-1364.
  6. (orange) Pollen distributions, interpreted temperature, Europe: [abstract] [full
text] [DOI] Davis, B.A.S., S. Brewer, A.C. Stevenson, J. Guiot (2003). “The temperature of Europe during the Holocene reconstructed from pollen data”. Quaternary Science Reviews 22: 1701-1716.
  7. (red) EPICA ice core, interpreted site temperature, Central Antarctica: [DOI] Stenni, B., J. Jouzel, V. Masson-Delmotte R. Roethlisberger, E. Castellano, O. Cattani, S. Falourd, S.J. Johnsen, A. Longinelli, J.P. Sachs, E. Selmo, R. Souchez, J.P. Steffensen, R. Udisti (2003). “A late-glacial high-resolution site and source temperature record derived from the EPICA Dome C isotope records (East Antarctica)”. Earth and Planetary Science Letters 217: 183-195.
  8. (dark red) Composite sediment cores, interpreted sea surface temperature, Western Tropical Pacific: L.D. Stott, K.G. Cannariato, R. Thunell, G.H. Haug, A. Koutavas, and S. Lund (2004). “Decline of surface temperature and salinity in the western tropical Pacific Ocean in the Holocene epoch”. Nature 431: 56-59.

Additional data used in inset plot and for matching temperature scale to modern values. Colors match those used in Image:2000 Year Temperature Comparison.png.

  1. (orange 200-1995): [abstract] [full text] [DOI] Jones, P.D. and M.E. Mann (2004). “Climate Over Past Millennia”. Reviews of Geophysics 42: RG2002.
  2. (red-orange 1500-1980): [abstract] [DOI] Huang, S. (2004). “Merging Information from Different Resources for New Insights into Climate Change in the Past and Future”. Res Lett. 31: L13205.
  3. (red 1-1979): [abstract] [full text] [DOI] Moberg, A., D.M. Sonechkin, K. Holmgren, N.M. Datsenko and W. Karlén (2005). “Highly variable Northern Hemisphere temperatures reconstructed from low- and high-resolution proxy data”. Nature 443: 613- 617.
  4. (thinblackline1856-2004):Instrumentalglobalannualdataset
TaveGL2v [3]: [abstract] Jones, P.D. and A. Moberg (2003). “Hemispheric and large- scale surface air temperature variations: An extensive revision and an update to
2001”. Journal of Climate 16: 206-223.

APPENDIX A.2

Rohde, R.A. (2006) Reconstructed Temperature: Expansion of the Last 1000 Years.

  1. (dark blue 1000-1991): P.D. Jones, K.R. Briffa, T.P. Barnett, and S.F.B. Tett (1998). “High-resolution Palaeoclimatic Records for the last Millennium: Interpretation, Integration and Comparison with General Circulation Model Control-run Temperatures”. The Holocene 8: 455-471.doi:10.1191/095968398667194956
  2. (blue 1000-1980): M.E. Mann, R.S. Bradley, and M.K. Hughes (1999). “Northern Hemisphere Temperatures During the Past Millennium: Inferences, Uncertainties, and Limitations”. Geophysical Research Letters 26 (6): 759-762.
  3. (light blue 1000-1965): Crowley and Lowery (2000). “Northern Hemisphere Temperature Reconstruction”. Ambio 29: 51-54. Modified as published in Crowley (2000). “Causes of Climate Change Over the Past 1000 Years”. Science 289: 270- 277. doi:10.1126/science.289.5477.270
  4. (lightest blue 1402-1960): K.R. Briffa, T.J. Osborn, F.H. Schweingruber, I.C. Harris, P.D. Jones, S.G. Shiyatov, S.G. and E.A. Vaganov (2001). “Low-frequency temperature variations from a northern tree-ring density network”. Geophys. Res. 106: 2929-2941.
  5. (light turquoise 831-1992): J. Esper, E.R. Cook, and F.H. Schweingruber (2002). “Low- Frequency Signals in Long Tree-Ring Chronologies for Reconstructing Past Temperature Variability”.Science 295 (5563): 2250-2253. doi:10.1126/science.1066208.
  6. (green 200-1980): M.E. Mann and P.D. Jones (2003). “Global Surface Temperatures over the Past Two Millennia”. Geophysical Research Letters 30 (15):
1820. doi:10.1029/2003GL017814.
  7. (yellow 200-1995): P.D. Jones and M.E. Mann (2004). “Climate Over Past Millennia”. Reviews of Geophysics 42: RG2002. doi:10.1029/2003RG000143
  8. (orange 1500-1980): S. Huang (2004). “Merging Information from Different Resources for New Insights into Climate Change in the Past and Future”. Res Lett. 31: L13205.doi:10.1029/2004GL019781
  9. (red 1-1979): A. Moberg, D.M. Sonechkin, K. Holmgren, N.M. Datsenko and W. Karlén (2005). “Highly variable Northern Hemisphere temperatures reconstructed from low- and high-resolution proxy data”. Nature 443: 613-617. doi:10.1038/nature03265
  10. dark red 1600-1990): J.H. Oerlemans (2005). “Extracting a Climate Signal from 169 Glacier Records”. Science 308: 675-677. doi:10.1126/science.1107046
  11. (black 1856-2004): Instrumental data was jointly compiled by the w:Climatic Research Unit and the UK Meteorological Office Hadley Centre. Global Annual Average data set TaveGL2v [2]was used.
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