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Climatic constraints on maximum levels of human metabolic activity and their relation to human evolution and global change

Abstract

No matter what humans do, their levels of metabolic activity are linked to the climatic conditions of the land surface. On the one hand, the productivity of the terrestrial biosphere provides the source of chemical free energy to drive human metabolic activity. On the other hand, human metabolic activity results in the generation of heat within the body. The release of that heat to the surrounding environment is potentially constrained by the climatic conditions at the land surface. Both of these factors are intimately linked to climate: Climatic constraints act upon the productivity of the terrestrial biosphere and thereby the source of free energy, and the climatic conditions near the surface constrain the loss of heat from the human body to its surrounding environment. These two constraints are associated with a fundamental trade-off, which should result in a distinct maximum in possible levels of human metabolic activity for certain climatic conditions. For present-day conditions, tropical regions are highly productive and provide a high supply rate of free energy. But the tropics are also generally warm and humid, resulting in a low ability to loose heat, especially during daylight. Contrary, polar regions are much less productive, but allow for much higher levels of heat loss to the environment. This trade-off should therefore result in an optimum latitude (and altitude) at which the climatic environment allows humans to be metabolically most active and perform maximum levels of physical work. Both of these constraints are affected by the concentration of atmospheric carbon dioxide pCO 2, but in contrary ways, so that I further hypothesize that an optimum concentration of pCO 2 exists and that the optimum latitude shifts with pCO 2. I evaluate these three hypotheses with model simulations of an Earth system model of intermediate complexity which includes expressions for the two constraints on maximum possible levels of human metabolic activity. This model is used to perform model simulations for the present-day and sensitivity experiments to different levels of pCO 2. The model simulations support the three hypotheses and quantify the conditions under which these apply. Although the quantification of these constraints on human metabolic activity is grossly simplified in the approach taken here, the predictions following from this approach are consistent with the geographic locations of where higher civilizations first emerged. Applied to past climatic changes, this perspective can explain why major evolutionary events in human evolutionary history took place at times of global cooling. I conclude that the quantification of these constraints on human metabolic activity is a meaningful and quantitative measure of the “human habitability” of the Earth’s climate. When anthropogenic climate change is viewed from this perspective, an important implication is that global warming is likely to lead to environmental conditions less suitable for human metabolic activity in their natural environment (and for large mammals in general) due to a lower ability to loose heat.

References

  • Allman JM (1999) Evolving brains. Scientific American Library, New York

    Google Scholar 

  • Campbell GS, Norman JM (1998) An introduction to environmental biophysics, 2nd edn. Springer Publishers, New York, NY

    Google Scholar 

  • Cerling TE, Harris JM, MacFadden BJ, Leakey MG, Quade J, Eisenmann V, Ehleringer JR (1997) Global vegetation change through the Miocene/Pliocene boundary. Nature 389:153–158

    Article  Google Scholar 

  • Chaisson EJ (2001) Cosmic evolution: rise of complexity in nature. Harvard University Press, Cambridge, MA

    Google Scholar 

  • Cramer W, Bondeau A, Woodward FI, Prentice IC, Betts RA, Brovkin V, Cox PM, Fischer V, Foley JA, Friend AD, Kucharik C, Lomas MR, Ramankutty N, Sitch S, Smith B, White A, Young-Molling C (2001) Global response of terrestrial ecosystem structure and function to CO2 and climate change: results from six dynamic global vegetation models. Glob Chang Biol 7:357–373

    Article  Google Scholar 

  • Crowley TJ, North GR (1991) Paleoclimatolgy. Oxford University Press, New York

    Google Scholar 

  • Diamond J (1997) Guns, germs, and steel: the fates of human societies. Norton and Company, Inc., New York, NY

    Google Scholar 

  • Field CB, Behrenfeld MJ, Randerson JT, Falkowski P (1998) Primary production of the biosphere: integrating terrestrial and oceanic components. Science 281:237–240

    Article  Google Scholar 

  • Fraedrich K, Jansen H, Kirk E, Luksch U, Lunkeit F (2005a) The planet simulator: towards a user friendly model. Z Meteorol 14:299–304

    Article  Google Scholar 

  • Fraedrich K, Jansen H, Kirk E, Lunkeit F (2005b) The planet simulator: green planet and desert world. Z Meteorol 14:305–314

    Article  Google Scholar 

  • Hammond KA, Diamond J (1997) Maximal sustained energy budgets in humans and animals. Nature 386:457–462

    Article  Google Scholar 

  • Haug GA, Guenther D, Peterson LC, Sigman DM, Hughen KA, Aeschlimann B (2003) Climate and the collapse of Maya civilization. Science 299:1731–1735

    Article  Google Scholar 

  • Huntington E (1915) Civilization and climate. Yale University Press, New Haven, Conn

    Google Scholar 

  • Imhoff ML, Bounoua L, Ricketts T, Loucks C, Harriss R, Lawrence WT (2004) Global patterns in human consumption of net primary production’. Nature 429:870–873

    Article  Google Scholar 

  • IPCC (2001) Climate change 2001: the scientific basis. Contribution of working group I to the third assessment report of the intergovernmental panel on climate change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA

    Google Scholar 

  • Kleidon A (2002) Testing the effect of life on earth’s functioning: how Gaian is the earth system? Clim Change 66:271–319

    Article  Google Scholar 

  • Kleidon A (2004) Beyond Gaia: thermodynamics of life and earth system functioning. Clim Change 66:271–319

    Article  Google Scholar 

  • Kleidon A (2006) The climate sensitivity to human appropriation of vegetation productivity and its thermodynamic characterization. Glob Planet Change 54:109–127

    Article  Google Scholar 

  • Kleidon A, Lorenz RD (eds) (2005) Non-equilibrium thermodynamics and the production of entropy: life, earth, and beyond. Springer Verlag, Heidelberg, Germany

    Google Scholar 

  • Kothavala Z, Oglesby RJ, Saltzman B (1999) Sensitivity of equilibrium surface temperature of CCM3 to systematic changes in atmospheric CO2. Geophys Res Lett 26:209–212

    Article  Google Scholar 

  • Lamb HH (1982) Climate, history and the modern world. Routledge, London, New York

    Google Scholar 

  • Larcher W (1995) Plant physiological ecology, 3rd edn. Springer Publishers, New York, NY

    Google Scholar 

  • Lear CH, Elderfield H, Wilson PA (2000) Cenozoic deep-sea temperatures and global ice volumes from Mg/Ca in benthic foraminiferal calcite. Science 287:269–272

    Article  Google Scholar 

  • Long SP, Ainsworth EA, Leakey ADB, Noesberger J, Ort DR (2006) Food for thought: lower-than-expected crop yield stimulation with rising CO2 concentrations. Science 312:1918–1921

    Article  Google Scholar 

  • Lunkeit F, Fraedrich K, Jansen H, Kirk E, Kleidon A, Luksch U (2004) Planet simulator reference manual. Available at http://puma.dkrz.de/plasim

  • Monteith JL, Huda AKS, Midya D (1989) RESCAP: a resource capture model for sorghum and pearl millet. In: Virmani SM, Tandon HLS, Alagarswamy G (eds) Modelling the growth and development of sorghum and pearl millet, Vol 12. ICRISAT Research Bulletin, Patancheru, India, pp 30–34

    Google Scholar 

  • Odum HT (1988) Self-organization, transformity, and information. Science 242:1132–1139

    Article  Google Scholar 

  • Oglesby RJ, Saltzman B (1992) Equilibrium climate statistics of a general circulation model as a function of atmospheric carbon dioxide. I - Geographic distributions of primary variables. J Clim 5:66–92

    Article  Google Scholar 

  • Ozawa H, Ohmura A, Lorenz RD, Pujol T (2003) The second law of thermodynamics and the global climate system – a review of the maximum entropy production principle. Rev Geophys 41:1018

    Article  Google Scholar 

  • Pearson PN, Palmer MR (2000) Atmospheric carbon dioxide concentrations over the past 60 million years. Nature 406:695–699

    Article  Google Scholar 

  • Peixoto JP, Oort AH (1992) Physics of climate. American Institute of Physics, New York, NY

    Google Scholar 

  • Petit JR, Jouzel J, Raynaud D, Barkov NI, Barnola J-M, Basile I, Bender M, Chappellaz J, Davis M, Delaygue G, Kotlyakov VM, Legrand M, Lipenkov VY, Lorius C, Pepin 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 399:429–439

    Article  Google Scholar 

  • Ritter C (1852) Einleitung zur Allgemeinen vergleichenden Geographie und Abhandlungen zur Begründung einer mehr wissenschaftlichen Behandlung der Erdkunde. G. Reimer, Berlin

    Google Scholar 

  • Rojstaczer S, Sterling SM, Moore NJ (2001) Human appropriation of photosynthesis products. Science 294:2549–2552

    Article  Google Scholar 

  • Sage RF (1995) Was low atmospheric CO2 during the Pleistocene a limiting factor for the origin of agriculture? Glob Chang Biol 1:93–106

    Article  Google Scholar 

  • Schrödinger E (1944) What is life? The physical aspect of the living cell. Cambridge University Press, Cambridge, UK

    Google Scholar 

  • Schwartzman DW, Middendorf G (2000) Biospheric cooling and the emergence of intelligence. In: Lemarchand G, Meech K (eds) A new era in bioastronomy, Vol 213. ASP Conference Series, pp 425–429

  • Smil V (1999) Energies - an illustrated guide to the biosphere and civilization. MIT Press, Cambridge, Massachusetts

    Google Scholar 

  • Vitousek PM, Ehrlich PR, Ehrlich AH, Matson PA (1986) Human appropriation of the products of photosynthesis. Bioscience 36:368–373

    Article  Google Scholar 

  • Vitousek PM, Mooney HA, Lubchenco J, Melillo JM (1997) Human domination of earth’s ecosystems. Science 277:494–499

    Article  Google Scholar 

  • Vrba ES (1995) The fossil record of African Antelopes (Mammalia, Bovidae) in relation to human evolution and paleoclimate. In: Vrba ES, Denton GH, Partridge TC, Burckle LH (eds) Paleoclimate and evolution, with emphasis on human origins. Yale University Press, New Haven, CT, and London, UK, pp 385–424

    Google Scholar 

  • Vrba ES, Denton GH, Partridge TC, Burckle LH (eds) (1995) Paleoclimate and evolution, with emphasis on human origins. Yale University Press, New Haven, CT, and London, UK

    Google Scholar 

  • Zachos J, Pagani M, Sloan L, Thomas E, Billups K (2001) Trends, rhythms, and aberrations in global climate 65 Ma to present. Science 292:686–693

    Article  Google Scholar 

  • Zotin AI (1984) Bioenergetic trends of evolutionary progress of organisms. In: Lamprecht I, Zotin AI (eds) Thermodynamics and regulation of biological processes. de Gruyter, Berlin, New York, pp 451–458

    Google Scholar 

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Correspondence to Axel Kleidon.

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Kleidon, A. Climatic constraints on maximum levels of human metabolic activity and their relation to human evolution and global change. Climatic Change 95, 405–431 (2009). https://doi.org/10.1007/s10584-008-9537-3

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Keywords

  • Heat Loss
  • Supply Rate
  • Earth System Model
  • High Civilization
  • Climatic Environment