Low atmospheric carbon dioxide (CO2) concentration1 during the Little Ice Age has been used to derive the global carbon cycle sensitivity to temperature2. Recent evidence3 confirms earlier indications4 that the low CO2 was caused by increased terrestrial carbon storage. It remains unknown whether the terrestrial biosphere responded to temperature variations, or there was vegetation re-growth on abandoned farmland5. Here we present a global numerical simulation of atmospheric carbonyl sulfide concentrations in the pre-industrial period. Carbonyl sulfide concentration is linked to changes in gross primary production6 and shows a positive anomaly7 during the Little Ice Age. We show that a decrease in gross primary production and a larger decrease in ecosystem respiration is the most likely explanation for the decrease in atmospheric CO2 and increase in atmospheric carbonyl sulfide concentrations. Therefore, temperature change, not vegetation re-growth, was the main cause of the increased terrestrial carbon storage. We address the inconsistency between ice-core CO2 records from different sites8 measuring CO2 and δ13CO2 in ice from Dronning Maud Land (Antarctica). Our interpretation allows us to derive the temperature sensitivity of pre-industrial CO2 fluxes for the terrestrial biosphere (γL = −10 to −90 Pg C K−1), implying a positive climate feedback and providing a benchmark to reduce model uncertainties9.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1.

    et al. Law Dome CO2, CH4 and N2O ice core records extended to 2000 years BP. Geophys. Res. Lett. 33, L14810 (2006).

  2. 2.

    & Climate change—illuminating the modern dance of climate and CO2. Science 321, 1642–1644 (2008).

  3. 3.

    et al. Links between atmospheric carbon dioxide, the land carbon reservoir and climate over the past millennium. Nature Geosci. 8, 383–387 (2015).

  4. 4.

    , , , & Long-term variability in the global carbon cycle inferred from a high-precision CO2 and δ13C ice-core record. Tellus B 51, 233–248 (1999).

  5. 5.

    Climate or humans? Nature Geosci. 8, 335–336 (2015).

  6. 6.

    et al. On the global distribution, seasonality, and budget of atmospheric carbonyl sulfide (COS) and some similarities to CO2. J. Geophys. Res. 112, D09302 (2007).

  7. 7.

    , , & Carbonyl sulfide in air extracted from a South Pole ice core: a 2000 year record. Atmos. Chem. Phys. 8, 7533–7542 (2008).

  8. 8.

    et al. Atmospheric CO2 over the last 1000 years: a high-resolution record from the West Antarctic Ice Sheet (WAIS) Divide ice core. Glob. Biogeochem. Cycles 26, GB2027 (2012).

  9. 9.

    et al. Uncertainties in CMIP5 climate projections due to carbon cycle feedbacks. J. Clim. 27, 511–526 (2014).

  10. 10.

    et al. Inter-hemispheric temperature variability over the past millennium. Nature Clim. Change 4, 362–367 (2014).

  11. 11.

    The early anthropogenic hypothesis: challenges and responses. Rev. Geophys. 45, RG4001 (2007).

  12. 12.

    et al. A coupled model of the global cycles of carbonyl sulfide and CO2: a possible new window on the carbon cycle. J. Geophys. Res. 118, 842–852 (2013).

  13. 13.

    , , , & Global budget of atmospheric carbonyl sulfide: temporal and spatial variations of the dominant sources and sinks. J. Geophys. Res. 107, 4658 (2002).

  14. 14.

    , , & Coupled climate–carbon simulations indicate minor global effects of wars and epidemics on atmospheric CO2 between 800 and 1850. Holocene 21, 843–851 (2011).

  15. 15.

    , & The effects of land use and climate change on the carbon cycle of Europe over the past 500 years. Glob. Change Biol. 18, 902–914 (2012).

  16. 16.

    , , & Ice-core records of biomass burning. Anthropocene Rev. (2015).

  17. 17.

    et al. Carbon–concentration and carbon–climate feedbacks in CMIP5 earth system models. J. Clim. 26, 5289–5314 (2013).

  18. 18.

    , , , & Highly variable Northern Hemisphere temperatures reconstructed from low- and high-resolution proxy data. Nature 433, 613–617 (2005).

  19. 19.

    et al. Global signatures and dynamical origins of the Little Ice Age and medieval climate anomaly. Science 326, 1256–1260 (2009).

  20. 20.

    & The extra-tropical Northern Hemisphere temperature in the last two millennia: reconstructions of low-frequency variability. Clim. Past 8, 765–786 (2012).

  21. 21.

    Continental-scale temperature variability during the past two millennia. Nature Geosci. 6, 339–346 (2013).

  22. 22.

    et al. Supporting evidence from the EPICA Dronning Maud Land ice core for atmospheric CO2 changes during the past millennium. Tellus B 57, 51–57 (2005).

  23. 23.

    et al. A revised 1000 year atmospheric δ13C-CO2 record from Law Dome and South Pole, Antarctica. J. Geophys. Res. 118, 8482–8499 (2013).

  24. 24.

    et al. Observing and modeling the influence of layering on bubble trapping in polar firn. J. Geophys. Res. 120, 2558–2574 (2015).

  25. 25.

    , , & Kalman filter analysis of ice core data 2. Double deconvolution of CO2 and δ13C measurements. J. Geophys. Res. 107, 4423 (2002).

  26. 26.

    et al. Ensemble reconstruction constraints on the global carbon cycle sensitivity to climate. Nature 463, 527–530 (2010).

  27. 27.

    , , & How positive is the feedback between climate change and the carbon cycle? Tellus B 55, 692–700 (2003).

  28. 28.

    et al. Carbon dioxide and climate impulse response functions for the computation of greenhouse gas metrics: a multi-model analysis. Atmos. Chem. Phys. 13, 2793–2825 (2013).

  29. 29.

    , & Positive feedback between global warming and atmospheric CO2 concentration inferred from past climate change. Geophys. Res. Lett. 33, L10702 (2006).

  30. 30.

    & Defining the anthropocene. Nature 519, 171–180 (2015).

  31. 31.

    et al. Atmospheric carbonyl sulfide sources from anthropogenic activity: implications for carbon cycle constraints. Geophys. Res. Lett. 42, 3004–3010 (2015).

  32. 32.

    et al. Photosynthetic control of atmospheric carbonyl sulfide during the growing season. Science 322, 1085–1088 (2008).

  33. 33.

    et al. Sources and sinks of carbonyl sulfide in an agricultural field in the Southern Great Plain. Proc. Natl Acad. Sci. USA 111, 9064–9069 (2014).

  34. 34.

    , , & Association between COS uptake and 18Δ during gas exchange in C3 and C4 leaves. Plant Physiol. 157, 509–517 (2011).

  35. 35.

    , , & Photochemical and physical modeling of carbonyl sulfide in the ocean. J. Geophys. Res. 108, 3229 (2003).

  36. 36.

    , , , & A new model for the global biogeochemical cycle of carbonyl sulfide - Part 1: Assessment of direct marine emissions with an oceanic general circulation and biogeochemistry model. Atmos. Chem. Phys. Discuss. 14, 20677–20720 (2014).

  37. 37.

    et al. Carbonyl sulfide hydrolysis in Antarctic ice cores and an atmospheric history for the last 8000 years. J. Geophys. Res. 119, 8500–8514 (2014).

  38. 38.

    , , & A medium depth ice core drill. Mem. Natl Inst. Polar Res. 56, 82–90 (2002).

  39. 39.

    et al. Changes in the global atmospheric methane budget over the last decades inferred from 13C and D isotopic analysis of Antarctic firn air. J. Geophys. Res. 106, 20456–20481 (2001).

  40. 40.

    et al. Modeling air movement and bubble trapping in firn. J. Geophys. Res. 102, 6747–6763 (1997).

  41. 41.

    et al. How well do different tracers constrain the firn diffusivity profile? Atmos. Chem. Phys. 13, 1485–1510 (2013).

  42. 42.

    et al. Firn accumulation records for the past 1000 years on the basis of dielectric profiling of six cores from Dronning Maud Land, Antarctica. J. Glaciol. 169, 279–291 (2004).

  43. 43.

    et al. An independently dated 2000-yr volcanic record from Law Dome, East Antarctica, including a new perspective on the dating of the 1450s CE eruption of Kuwae, Vanuatu. Clim. Past 8, 1929–1940 (2012).

  44. 44.

    et al. In search of in situ radiocarbon in Law Dome ice and firn. Nucl. Instrum. Methods Phys. Res. B 172, 610–622 (2000).

  45. 45.

    Inverse problems and complexity in earth system science. In Complex Physical, Biophysical and Econophysical Systems. Proc. 22nd Canberra Int. Phys. Summer School (The Australian National University, 2010).

  46. 46.

    Laplace transform analysis of the carbon cycle. Environ. Modelling Softw. 22, 1488–1497 (2007).

  47. 47.

    et al. Climate and carbon cycle dynamics in a CESM simulation from 850 to 2100 CE. Earth Syst. Dyn. 6, 411–434 (2015).

  48. 48.

    et al. Carbon Cycle Variability During the Last Millennium and Last Deglaciation PhD thesis, Oregon State Univ. (2013).

Download references


This work was undertaken as part of the Australian Climate Change Science Program, funded by the Australian government—Department of the Environment, the Bureau of Meteorology and CSIRO. We thank S. Coram, R. Gregory, D. Thornton and D. Spencer of CSIRO for their analytical support and S. Allin for ice handling. W. Sturges recognizes the CSIRO Fröhlich Fellowship for supporting a visit to CSIRO, Aspendale. P.J.R. was supported by an Australian Professorial Fellowship (DP1096309). M.R.’s visit to CSIRO and D.M.E.’s visit to the Second University of Naples were supported by the Italian POLIGRID project (CUP B65B0900002007). The DML ice was sampled using funding from the Natural Environment Research Council (grant NE/F021194/1). We thank the British Antarctic Survey for providing DML ice samples. The Australian Antarctic Science Program and ANSTO supported drilling of DSS0506 through the AINSE grant and AAS grants 4061 and 3064. We thank P. Fraser for useful comments.

Author information

Author notes

    • M. Rubino

    Present address: Dipartimento di Matematica e Fisica, Seconda Università di Napoli, Viale Lincoln 5, 81100 Caserta, Italy.


  1. CSIRO Oceans and Atmosphere, PMB 1, Aspendale, Victoria 3195, Australia

    • M. Rubino
    • , D. M. Etheridge
    • , C. M. Trudinger
    • , C. E. Allison
    • , I. Enting
    • , L. P. Steele
    •  & R. L. Langenfelds
  2. School of Earth Sciences, University of Melbourne, 3010 Victoria, Australia

    • P. J. Rayner
  3. ARC Centre of Excellence for Mathematics and Statistics of Complex Systems (MASCOS), University of Melbourne, 3010 Victoria, Australia

    • I. Enting
  4. British Antarctic Survey, Madingley Road, Cambridge CB3 0ET, UK

    • R. Mulvaney
  5. Centre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, Norwich, Norfolk NR4 7TJ, UK

    • W. T. Sturges
  6. Australian Antarctic Division, 203 Channel Highway, Kingston, Tasmania 7050, Australia

    • M. A. J. Curran
  7. Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Hobart 7001, Australia

    • M. A. J. Curran
  8. Australian Nuclear Science and Technology Organisation (ANSTO), PMB 1, Menai, New South Wales 2234, Australia

    • A. M. Smith


  1. Search for M. Rubino in:

  2. Search for D. M. Etheridge in:

  3. Search for C. M. Trudinger in:

  4. Search for C. E. Allison in:

  5. Search for P. J. Rayner in:

  6. Search for I. Enting in:

  7. Search for R. Mulvaney in:

  8. Search for L. P. Steele in:

  9. Search for R. L. Langenfelds in:

  10. Search for W. T. Sturges in:

  11. Search for M. A. J. Curran in:

  12. Search for A. M. Smith in:


D.M.E. conceived the study. D.M.E. and M.R. planned the project. D.M.E., A.M.S., M.A.J.C., R.M. and W.T.S. sampled, dated and provided ice cores. M.R., D.M.E., C.E.A., R.L.L. and L.P.S. carried out the measurements. C.M.T. developed and ran the firn modelling and the KFDD. P.J.R., M.R., C.M.T. and D.M.E. developed the COS model and interpreted the results. I.E., M.R., D.M.E. and C.M.T. performed the carbon sensitivity to temperature analysis. All authors contributed to results interpretation and manuscript writing.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to M. Rubino.

Supplementary information

About this article

Publication history