Skip to main content

Thank you for visiting nature.com. 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.

Earth science

Free and forced climate variations

Nature volume 517, pages 562–563 (2015)Cite this article

Subjects

A combination of simulations and data shows that short-term climate trends are dominated by natural internal variations, providing a basis for climate forecasting, but not for assessing sensitivity to forced changes. See Article p.565

It has long been known that the global surface temperature fluctuates on multidecadal timescales in response to natural variations in ocean circulation and other processes. Since at least the 1930s, climatologists have used 30-year averages as a standard climate 'normal' to smooth out decadal variations3. The 1995 Intergovernmental Panel on Climate Change report4 identified volcanic activity, variations in incoming solar radiation, and ocean circulation as drivers of decadal and longer variability in global surface temperature. An innovation of Marotzke and Forster's work is their use of coupled ocean–atmosphere climate-model runs5 to extract the contributions of processes internal to the climate system (free variation) that are due mainly to ocean circulation and its coupling with the atmosphere, and the contributions of external processes (forced variation) such as volcanoes, variations in greenhouse-gas concentrations and solar output.

This is a preview of subscription content

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

Buy

All prices are NET prices.

Figure 1: Fifteen-year temperature trends.

Notes

  1. See all news & views

References

  1. Stocker, T. F. et al. in Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (eds Stocker, T. F. et al.) 33–115 (Cambridge Univ. Press, 2013).

    Google Scholar 

  2. Marotzke, J. & Forster, P. M. Nature 517, 565–570 (2015).

    CAS  Article  ADS  Google Scholar 

  3. Arguez, A. & Vose, R. S. Bull. Am. Met. Soc. 92, 699–704 (2011).

    Article  ADS  Google Scholar 

  4. Houghton, J. T. et al. (eds) Climate Change 1995: The Science of Climate Change (Cambridge Univ. Press, 1996).

    Google Scholar 

  5. Taylor, K. E., Stouffer, R. J. & Meehl. G. A. Bull. Am. Met. Soc. 93, 485–498 (2012).

    Article  ADS  Google Scholar 

  6. Fyfe, J. C., Gillett, N. P. & Zwiers, F. W. Nature Clim. Change 3, 767–769 (2013).

    Article  ADS  Google Scholar 

  7. Otto, A. et al. Nature Geosci. 6, 415–416 (2013).

    CAS  Article  ADS  Google Scholar 

  8. Risbey, J. S. et al. Nature Clim. Change 4, 835–840 (2014).

    Article  ADS  Google Scholar 

  9. Meehl, G. A., Teng, H. & Arblaster, J. M. Nature Clim. Change 4, 898–902 (2014).

    Article  ADS  Google Scholar 

  10. England, M. H. et al. Nature Clim. Change 4, 222–227 (2014).

    Article  ADS  Google Scholar 

  11. Forster, P. M. et al. J. Geophys. Res. 118, 1139–1150 (2013).

    Article  Google Scholar 

  12. O'Kane, T. J. et al. Ocean Model. 69, 1–21 (2013).

    Article  ADS  Google Scholar 

  13. Meehl, G. A. et al. Bull. Am. Met. Soc. 95, 243–267 (2014).

    Article  ADS  Google Scholar 

  14. Cowtan, K. & Way, R. G. Q. J. R. Met. Soc. 140, 1935–1944 (2014).

    Article  ADS  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. James Risbey is in the Oceans and Atmosphere Flagship, Commonwealth Scientific and Industrial Research Organisation, Hobart, Tasmania 7001, Australia.,

    James Risbey

Authors
  1. James Risbey
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to James Risbey.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Risbey, J. Free and forced climate variations. Nature 517, 562–563 (2015). https://doi.org/10.1038/517562a

Download citation

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/517562a

Further reading

Search

Advanced search

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