Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.


Quantification of ocean heat uptake from changes in atmospheric O2 and CO2 composition

This article was retracted on 25 September 2019

This article has been updated


The ocean is the main source of thermal inertia in the climate system1. During recent decades, ocean heat uptake has been quantified by using hydrographic temperature measurements and data from the Argo float program, which expanded its coverage after 20072,3. However, these estimates all use the same imperfect ocean dataset and share additional uncertainties resulting from sparse coverage, especially before 20074,5. Here we provide an independent estimate by using measurements of atmospheric oxygen (O2) and carbon dioxide (CO2)—levels of which increase as the ocean warms and releases gases—as a whole-ocean thermometer. We show that the ocean gained 1.33 ± 0.20  × 1022 joules of heat per year between 1991 and 2016, equivalent to a planetary energy imbalance of 0.83 ± 0.11 watts per square metre of Earth’s surface. We also find that the ocean-warming effect that led to the outgassing of O2 and CO2 can be isolated from the direct effects of anthropogenic emissions and CO2 sinks. Our result—which relies on high-precision O2 measurements dating back to 19916—suggests that ocean warming is at the high end of previous estimates, with implications for policy-relevant measurements of the Earth response to climate change, such as climate sensitivity to greenhouse gases7 and the thermal component of sea-level rise8.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Prices vary by article type



Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Change in global ocean heat content (ΔOHC).
Fig. 2: Processes contributing to observed changes in atmospheric potential oxygen (ΔAPOOBS).
Fig. 3: Databased estimates of global ΔAPOClimate.
Fig. 4: Observed link between potential oxygen and ocean heat.

Data availability

Scripps APO data are available at APOClimate data, contributions to APOOBS and ocean heat content time series are available in Extended Data Figs. 14 and Extended Data Tables 15. Model results are available upon reasonable request to R.W. (IPSL anthropogenic aerosol simulations), L.B. (IPSL-CM5A-LR), M.C.L. (CESM-LE), J.P.D. (GFDL-ESM2M) or W.K. (UVic).

Change history

  • 19 November 2018

    Editor’s Note: We would like to alert readers that the authors have informed us of errors in the paper. An implication of the errors is that the uncertainties in ocean heat content are substantially underestimated. We are working with the authors to establish the quantitative impact of the errors on the published results, at which point in time we will provide a further update.

  • 25 September 2019

    This Article has been retracted; see accompanying Retraction Note.


  1. IPCC. Climate Change 2013: The Physical Science Basis (eds Stocker, T. F. et al.) (Cambridge Univ. Press, Cambridge, 2013).

  2. Abraham, J. P. et al. A review of global ocean temperature observations: implications for ocean heat content estimates and climate change. Rev. Geophys. 51, 450–483 (2013).

    Article  ADS  Google Scholar 

  3. Riser, S. C. et al. Fifteen years of ocean observations with the global Argo array. Nat. Clim. Chang e 6, 145–153 (2016).

    Article  ADS  Google Scholar 

  4. Boyer, T. et al. Sensitivity of global upper-ocean heat content estimates to mapping methods, XBT bias corrections, and baseline climatologies. J. Clim. 29, 4817–4842 (2016).

    Article  ADS  Google Scholar 

  5. Cheng, L. et al. XBT science: assessment of instrumental biases and errors. Bull. Am. Meteorol. Soc. 97, 924–933 (2016).

    Article  ADS  Google Scholar 

  6. Keeling, R. F. & Manning, A. C. in Treatise on Geochemistry 385–404 (Elsevier, Oxford, 2014).

  7. Forster, P. M. Inference of climate sensitivity from analysis of Earth’s energy budget. Annu. Rev. Earth Planet. Sci. 44, 85–106 (2016).

    Article  ADS  CAS  Google Scholar 

  8. Church, J. A. et al. in Climate Change 2013: The Physical Science Basis (eds Stocker, T. F. et al.) 1137–1216 (IPCC, Cambridge Univ. Press, Cambridge, 2013).

  9. Ishii, M. et al. Accuracy of global upper ocean heat content estimation expected from present observational data sets. Sci. Online Lett. Atmos. 13, 163–167 (2017).

    Google Scholar 

  10. Johnson, G. C. et al. Ocean heat content. Am. Meteorol. Soc. Bull. 98, S66–S68 (2017).

    Google Scholar 

  11. Desbruyères, D. G., Purkey, S. G., McDonagh, E. L., Johnson, G. C. & King, B. A. Deep and abyssal ocean warming from 35 years of repeat hydrography. Geophys. Res. Lett. 43, 10356–10365 (2016).

    Article  ADS  Google Scholar 

  12. Cheng, L. et al. Improved estimates of ocean heat content from 1960 to 2015. Sci. Adv. 3, e1601545 (2017).

    Article  ADS  Google Scholar 

  13. Allan, R. P. et al. Changes in global net radiative imbalance 1985–2012. Geophys. Res. Lett. 41, 5588–5597 (2014).

    Article  ADS  Google Scholar 

  14. Palmer, M. D. Reconciling estimates of ocean heating and Earth’s radiation budget. Curr. Clim. Change Rep. 3, 78–86 (2017).

    Article  Google Scholar 

  15. Loeb, N. G. et al. Observed changes in top-of-the-atmosphere radiation and upper-ocean heating consistent within uncertainty. Nat. Geosci. 5, 110–113 (2012).

    Article  ADS  CAS  Google Scholar 

  16. Battle, M. et al. Measurements and models of the atmospheric Ar/N2 ratio. Geophys. Res. Lett. 30, 1786 (2003).

    Article  ADS  Google Scholar 

  17. Ritz, S. P., Stocker, T. F. & Severinghaus, J. P. Noble gases as proxies of mean ocean temperature: sensitivity studies using a climate model of reduced complexity. Quat. Sci. Rev. 30, 3728–3741 (2011).

    Article  ADS  Google Scholar 

  18. Resplandy, L. et al. Constraints on oceanic meridional heat transport from combined measurements of oxygen and carbon. Clim. Dyn. 47, 3335–3357 (2016); erratum 49, 4317 (2017).

    Article  Google Scholar 

  19. Stephens, B. B. et al. Testing global ocean carbon cycle models using measurements of atmospheric O2 and CO2 concentration. Glob. Biogeochem. Cycles 12, 213–230 (1998).

    Article  ADS  CAS  Google Scholar 

  20. Le Quéré, C. et al. Global carbon budget 2016. Earth Syst. Sci. Data 8, 605–649 (2016).

    Article  ADS  Google Scholar 

  21. DeVries, T. The oceanic anthropogenic CO2 sink: storage, air-sea fluxes, and transports over the industrial era. Glob. Biogeochem. Cycles 28, 631–647 (2014).

    Article  ADS  CAS  Google Scholar 

  22. Wang, R. et al. Influence of anthropogenic aerosol deposition on the relationship between oceanic productivity and warming. Geophys. Res. Lett. 42, 10745–10754 (2015).

    Article  ADS  CAS  Google Scholar 

  23. Rietbroek, R., Brunnabend, S.-E., Kusche, J., Schröter, J. & Dahle, C. Revisiting the contemporary sea-level budget on global and regional scales. Proc. Natl Acad. Sci. USA 113, 1504–1509 (2016).

    Article  ADS  CAS  Google Scholar 

  24. IPCC. Climate Change 2007: Synthesis Report (eds Core Writing Team, Pachauri, R. K. & Reisinger, A.) (IPCC, Geneva, 2008).

  25. Keeling, R. F. & Severinghaus, J. P. in The Carbon Cycle (eds Wigley, T. M. L. & Schimel, D.) 134–140 (Cambridge Univ. Press, New York, 2000).

  26. Resplandy, L., Séférian, R. & Bopp, L. Natural variability of CO2 and O2 fluxes: what can we learn from centuries-long climate models simulations? J. Geophys. Res. Oceans 120, 384–404 (2015).

    Article  ADS  CAS  Google Scholar 

  27. Eddebbar, Y. A. et al. Impacts of ENSO on air-sea oxygen exchange: observations and mechanisms. Glob. Biogeochem. Cycles 31, 2017GB005630 (2017).

    Article  Google Scholar 

  28. Keeling, R. F. & Garcia, H. E. The change in oceanic O2 inventory associated with recent global warming. Proc. Natl Acad. Sci. USA 99, 7848–7853 (2002).

    Article  ADS  CAS  Google Scholar 

  29. Bopp, L., Le Quéré, C., Heimann, M., Manning, A. C. & Monfray, P. Climate-induced oceanic oxygen fluxes: implications for the contemporary carbon budget. Glob. Biogeochem. Cycles 16, 1022 (2002).

    Article  ADS  Google Scholar 

  30. Keeling, C. D., Piper, S. C., Whorf, T. P. & Keeling, R. F. Evolution of natural and anthropogenic fluxes of atmospheric CO2 from 1957 to 2003. Tellus B Chem. Phys. Meterol. 63, 1–22 (2011).

    Article  ADS  CAS  Google Scholar 

  31. Levitus, S. et al. World ocean heat content and thermosteric sea level change (0–2000 m), 1955–2010. Geophys. Res. Lett. 39, L10603 (2012).

    Article  ADS  Google Scholar 

  32. Olsen, A. et al. The Global Ocean Data Analysis Project version 2 (GLODAPv2)—an internally consistent data product for the world ocean. Earth Syst. Sci. Data 8, 297–323 (2016).

    Article  ADS  Google Scholar 

  33. Severinghaus, J. P. Studies of the Terrestrial O 2 and Carbon Cycles in Sand Dune Gases and in Biosphere. PhD Thesis, Columbia Univ. (1995).

  34. Hamme, R. C. & Keeling, R. F. Ocean ventilation as a driver of interannual variability in atmospheric potential oxygen. Tellus B Chem. Phys. Meterol. 60, 706–717 (2008).

    Article  ADS  Google Scholar 

  35. Andres, R. J., Boden, T. A. & Higdon, D. A new evaluation of the uncertainty associated with CDIAC estimates of fossil fuel carbon dioxide emission. Tellus B Chem. Phys. Meterol. 66, 23616 (2014).

    Article  ADS  Google Scholar 

  36. Keeling, R. F., Manning, A. C., Paplawsky, W. J. & Cox, A. C. On the long-term stability of reference gases for atmospheric O2/N2 and CO2 measurements. Tellus B Chem. Phys. Meterol. 59, 3–14 (2007).

    Article  ADS  Google Scholar 

  37. Ballantyne, A. P. et al. Audit of the global carbon budget: estimate errors and their impact on uptake uncertainty. Biogeosciences 12, 2565–2584 (2015).

    Article  ADS  Google Scholar 

  38. Bronselaer, B., Winton, M., Russell, J., Sabine, C. L. & Khatiwala, S. Agreement of CMIP5 simulated and observed ocean anthropogenic CO2 uptake. Geophys. Res. Lett. 44, 12298–12305 (2017).

    Article  ADS  Google Scholar 

  39. Oeschger, H., Siegenthaler, U., Schotterer, U. & Gugelmann, A. A box diffusion model to study the carbon dioxide exchange in nature. Tellus 27, 168–192 (1975).

    Article  ADS  CAS  Google Scholar 

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

    Article  ADS  Google Scholar 

  41. Wang, D., Gouhier, T. C., Menge, B. A. & Ganguly, A. R. Intensification and spatial homogenization of coastal upwelling under climate change. Nature 518, 390–394 (2015).

    Article  ADS  CAS  Google Scholar 

  42. Ito, T., Nenes, A., Johnson, M. S., Meskhidze, N. & Deutsch, C. Acceleration of oxygen decline in the tropical Pacific over the past decades by aerosol pollutants. Nat. Geosci. 9, 443–447 (2016).

    Article  ADS  CAS  Google Scholar 

  43. Jickells, T. D. et al. A reevaluation of the magnitude and impacts of anthropogenic atmospheric nitrogen inputs on the ocean. Glob. Biogeochem. Cycles 31, 289–305 (2017).

    ADS  CAS  Google Scholar 

  44. Somes, C. J., Landolfi, A., Koeve, W. & Oschlies, A. Limited impact of atmospheric nitrogen deposition on marine productivity due to biogeochemical feedbacks in a global ocean model. Geophys. Res. Lett. 43, 4500–4509 (2016).

    Article  ADS  CAS  Google Scholar 

  45. Aumont, O., Ethé, C., Tagliabue, A., Bopp, L. & Gehlen, M. PISCES-v2: an ocean biogeochemical model for carbon and ecosystem studies. Geosci. Model Dev. 8, 2465–2513 (2015).

    Article  ADS  CAS  Google Scholar 

  46. Talley, L. D. et al. Changes in ocean heat, carbon content, and ventilation: a review of the first decade of GO-SHIP global repeat hydrography. Annu. Rev. Marine Sci. 8, 185–215 (2016).

    Article  ADS  CAS  Google Scholar 

  47. Sarmiento, J. L. & Gruber, N. Sinks for anthropogenic carbon. Phys. Today 55, 30–36 (2002).

    Article  CAS  Google Scholar 

  48. Garcia, H. E. & Gordon, L. I. Oxygen solubility in seawater: better fitting equations. Limnol. Oceanogr. 37, 1307–1312 (1992).

    Article  ADS  CAS  Google Scholar 

  49. Gruber, N., Sarmiento, J. L. & Stocker, T. F. An improved method for detecting anthropogenic CO2 in the oceans. Glob. Biogeochem. Cycles 10, 809–837 (1996).

    Article  ADS  CAS  Google Scholar 

  50. Dunne, J. P. et al. GFDL’s ESM2 global coupled climate–carbon Earth system models. Part I: physical formulation and baseline simulation characteristics. J. Clim. 25, 6646–6665 (2012).

    Article  ADS  Google Scholar 

  51. Dunne, J. P. et al. GFDL’s ESM2 global coupled climate–carbon Earth system models. Part II: carbon system formulation and baseline simulation characteristics. J. Clim. 26, 2247–2267 (2013).

    Article  ADS  Google Scholar 

  52. Séférian, R., Iudicone, D., Bopp, L., Roy, T. & Madec, G. Water mass analysis of effect of climate change on air–sea CO2 fluxes: the Southern Ocean. J. Clim. 25, 3894–3908 (2012).

    Article  ADS  Google Scholar 

  53. Kay, J. E. et al. The Community Earth System Model (CESM) large ensemble project: a community resource for studying climate change in the presence of internal climate variability. Bull. Am. Meteorol. Soc. 96, 1333–1349 (2015).

    Article  ADS  Google Scholar 

  54. Keller, D. P., Oschlies, A. & Eby, M. A new marine ecosystem model for the University of Victoria Earth System Climate Model. Geosci. Model Dev. 5, 1195–1220 (2012).

    Article  ADS  Google Scholar 

  55. Bopp, L. et al. Multiple stressors of ocean ecosystems in the 21st century: projections with CMIP5 models. Biogeosciences 10, 6225–6245 (2013).

    Article  ADS  Google Scholar 

  56. Keller, D. P., Kriest, I., Koeve, W. & Oschlies, A. Southern Ocean biological impacts on global ocean oxygen. Geophys. Res. Lett. 43, 6469–6477 (2016).

    Article  ADS  CAS  Google Scholar 

  57. Long, M. C., Deutsch, C. & Ito, T. Finding forced trends in oceanic oxygen. Glob. Biogeochem. Cycles 30, 381–397 (2016).

    Article  ADS  CAS  Google Scholar 

  58. Taylor, K. E., Stouffer, R. J. & Meehl, G. A. An overview of CMIP5 and the experiment design. Bull. Am. Meteorol. Soc. 93, 485–498 (2012).

    Article  ADS  Google Scholar 

  59. Moore, J. K., Lindsay, K., Doney, S. C., Long, M. C. & Misumi, K. Marine ecosystem dynamics and biogeochemical cycling in the Community Earth System Model [CESM1(BGC)]: comparison of the 1990s with the 2090s under the RCP4.5 and RCP8.5 scenarios. J. Clim. 26, 9291–9312 (2013).

    Article  ADS  Google Scholar 

  60. Rödenbeck, C., Le Quéré, C., Heimann, M. & Keeling, R. F. Interannual variability in oceanic biogeochemical processes inferred by inversion of atmospheric O2/N2 and CO2 data. Tellus B Chem. Phys. Meterol. 60, 685–705 (2008).

    Article  ADS  Google Scholar 

  61. Hamme, R. C. Mechanisms controlling the global oceanic distribution of the inert gases argon, nitrogen and neon. Geophys. Res. Lett. 29, 35-1–35-4 (2002).

    Article  Google Scholar 

  62. Trenberth, K. E., Fasullo, J. T., von Schuckmann, K. & Cheng, L. Insights into Earth’s energy imbalance from multiple sources. J. Clim. 29, 7495–7505 (2016).

    Article  ADS  Google Scholar 

  63. WCRP Global Sea Level Budget Group. Global sea level budget 1993–present. Earth Syst. Sci. Data 10, 1551–1590 (2018).

    Article  ADS  Google Scholar 

  64. Morice, C. P., Kennedy, J. J., Rayner, N. A. & Jones, P. D. Quantifying uncertainties in global and regional temperature change using an ensemble of observational estimates: the HadCRUT4 data set. J. Geophys. Res. Atmos. 117, D08101 (2012).

    Article  ADS  Google Scholar 

  65. Hansen, J., Ruedy, R., Sato, M. & Lo, K. Global surface temperature change. Rev. Geophys. 48, RG4004 (2010).

    Article  ADS  Google Scholar 

  66. Vose, R. S. et al. NOAA’s merged land–ocean surface temperature analysis. Bull. Am. Meteorol. Soc. 93, 1677–1685 (2012).

    Article  ADS  Google Scholar 

  67. Keeling, R. F., Körtzinger, A. & Gruber, N. Ocean deoxygenation in a warming world. Annu. Rev. Mar. Sci. 2, 199–229 (2010).

    Article  ADS  Google Scholar 

  68. Helm, K. P., Bindoff, N. L. & Church, J. A. Observed decreases in oxygen content of the global ocean. Geophys. Res. Lett. 38, L23602 (2011).

    Article  ADS  Google Scholar 

  69. Ito, T., Minobe, S., Long, M. C. & Deutsch, C. Upper ocean O2 trends: 1958–2015. Geophys. Res. Lett. 44, 4214–4223 (2017).

    Article  ADS  CAS  Google Scholar 

  70. Schmidtko, S., Stramma, L. & Visbeck, M. Decline in global oceanic oxygen content during the past five decades. Nature 542, 335–339 (2017).

    Article  ADS  CAS  Google Scholar 

Download references


We thank M. Winton for useful suggestions. L.R. acknowledges support from the Climate Program Office of the National Oceanic and Atmospheric Administration (NOAA), grant NA13OAR4310219, and from the Princeton Environmental Institute. The National Center for Atmospheric Research (NCAR) is sponsored by the National Science Foundation (NSF). We also thank the people who maintain the APO time series at Scripps and the groups developing the models CESM, GFDL, IPSL and UViC, used in this study. The Scripps O2 program has been supported by a series of grants from the US NSF and the NOAA, most recently 1304270 and NA15OAR4320071. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the NSF and NOAA. We thank the staff at the Cape Grim Baseline Air Pollution Station of the Canadian Greenhouse Gas program for collection of air samples.

Reviewer information

Nature thanks L. Cheng, F. Primeau and the other anonymous reviewer(s) for their contribution to the peer review of this work.

Author information

Authors and Affiliations



L.R. directed the analysis of the datasets and models used here and shared responsibility for writing the manuscript; R.F.K. shared responsibility for writing the manuscript; R.W. performed simulations of anthropogenic aerosols; L.B., J.P.D., M.C.L., W.K. and A.O. provided model results. All authors contributed to the final version of the manuscript.

Corresponding author

Correspondence to L. Resplandy.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data figures and tables

Extended Data Fig. 1 Effects of anthropogenic aerosols on APO.

a, Anomaly, relative to 1850 levels, in deposition of atmospheric anthropogenic aerosols (N, P and Fe) at the air–sea interface between 1960 and 2007, derived from model simulations with and without aerosols22. b, Impact of aerosol eutrophication on atmospheric O2 (solid lines) and CO2 (dashed lines) for all aerosols (black lines) and for each aerosol taken individually (coloured lines). c, Overall impact of aerosol eutrophication on ΔAPOClimate referenced to the first year that has observations (1991).

Extended Data Fig. 2 Solubility-driven changes in ocean oxygen and carbon concentrations.

a, Ocean observations of O2*, O2sat, Cpi* and Cpisat as a function of potential temperature in the Glodapv2 database32. b, OPOsat ( = O2sat + 1.1Cpisat, in grey) and the expected effects on APO owing to the combined effects of OPOsat and the thermal exchanges of N2 ( = O2sat + 1.1Cpisat – XO2 / XN2 [N2 – mean(N2)], in red). For clarity only 16 × 103 points randomly picked out of the 78,456 data points available are shown for each variable. Note that very low values of O2* (around 450 μmol kg−1) at low temperature (less than 10 °C) correspond to data collected in the Arctic Ocean, where phosphate concentrations (used for O2* calculation) are comparatively lower than in other cold ocean regions. Low O2* values in the Arctic explain the relatively low values of OPO shown in Extended Data Fig. 3a at temperatures below 10 °C.

Extended Data Fig. 3 Link between OPO, APOClimate and ocean heat.

a, c–f, OPO concentrations (yellow) and OPO concentrations at saturation based on O2 and CO2 solubility (OPOsat, grey) as a function of ocean temperature in the GLODAPv2 database32 (a) and four Earth-system models (IPSL, GFDL, CESM and UVic; cf). Slopes give the OPO-to-temperature ratios in nmol J−1. b, The link between ΔAPOClimate and changes in ocean heat content (that is, ΔAPOClimate-to-ΔOHC ratio) in the four models is tied to their OPO-to-temperature ratios and can be constrained using the observed OPO-to-temperature of 4.45 nmol J−1 (vertical dashed lines). To avoid visual saturation, only 16,000 points, picked randomly, are shown for OPO.

Extended Data Fig. 4 Changes in APOClimate (ΔAPOClimate) and ocean heat content (ΔOHC) in four Earth-system models.

a, Simulated ΔAPOClimate (black outlines) are decomposed into the contributions (percentage of total) from changes in ocean thermal saturation (light blue) and biologically driven changes (dark blue), the latter including changes in photosynthesis/respiration and changes in ocean circulation that transport and mix gradients of biological origin. For each model, ΔAPOClimate is further decomposed into its O2, CO2 and N2 components—that is, how much of ΔAPOClimate is explained by changes in O2, CO2 and N2 air–sea fluxes due to ocean saturation changes and biologically driven changes. b, Model ΔAPOClimate-to-ΔOHC ratios over the 180 years of simulation (referenced to year 1991) in per meg per 1022 J units are: 0.85 ± 0.01 (CESM), 0.83 ± 0.01 (GFDL), 0.89 ± 0.03 (IPSL) and 0.99 ± 0.02 (UVic).

Extended Data Table 1 Sources of the hydrographic databased estimates of global changes in ocean heat content (ΔOHC) used in Fig. 1
Extended Data Table 2 Linear trends in global ocean heat content
Extended Data Table 3 Contributions to ΔAPOOBS, ΔAPOFF and ΔAPOCant and associated uncertainties (±1σ) during the observation period 1991–2016
Extended Data Table 4 Temporal evolution of the cumulative contributions to global APO changes and their 1σ uncertainties
Extended Data Table 5 Trends in air–sea flux of O2, CO2 and APO due to anthropogenic aerosol deposition

Source data

Rights and permissions

Reprints and Permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Resplandy, L., Keeling, R.F., Eddebbar, Y. et al. Quantification of ocean heat uptake from changes in atmospheric O2 and CO2 composition. Nature 563, 105–108 (2018).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing