Multiple Wrongs Don’t Make A Right on ENSO Impacts

The 2009 Foster et al paper (In Press) “Comment on ‘Influence of the Southern Oscillation on tropospheric temperature’ by J. D. McLean, C. R. de Freitas, and R. M. Carter” was written by a who’s who of climate scientists. The authors include G. Foster, J. D. Annan, P. D. Jones, M. E. Mann, B. Mullan, J. Renwick, J. Salinger, G. A. Schmidt, and K. E. Trenberth. Their comment is summarized by a sentence in the abstract: “Their [McLean, Freitas, and Carter’s] analysis is incorrect in a number of ways, and greatly overstates the influence of ENSO on the climate system.”

Link to Preprint (The Google link to the pdf version of the preprint is no longer operational):

http://74.125.47.132/search?q=cache:0hqurMRrw2UJ:www.cgd.ucar.edu/cas/Trenberth/trenberth.papers/FosteretalJGR09.pdf+Comment+on+%E2%80%9CInfluence+of+the+Southern+Oscillation+on+tropospheric+temperature%E2%80%9D+by+J.+D.+McLean,+C.+R.+de+Freitas,+and+R.+M.+Carter+(Foster+et+al+2009)&cd=1&hl=en&ct=clnk&gl=us

This post does not discuss the analysis by Carter et al nor does it examine the methods used by Foster et al to critique it. This post lists the papers cited by Foster et al that determine “the connection between ENSO and large-scale temperature variability, particularly with regard to the role of ENSO in any long-term warming trends, that has been carried out over the past two decades,” and discusses the errors that are common to those papers.

THE PAPERS CITED BY FOSTER ET AL

Jones, P.D., (1989), The influence of ENSO on global temperatures, Climate Monitor, 17, 80–89.

(I have not found a link to this paper. Since I haven’t read it, I can’t comment about it. It is, therefore, excluded from my post.)

Santer, B.D., Wigley, T.M.L., Doutriaux, C., Boyle, J.S., Hansen, J.E., Jones, P.D., Meehl, G.A., Roeckner, E., Sengupta, S., and Taylor K.E. (2001), Accounting for the effects of volcanoes and ENSO in comparisons of modeled and observed temperature trends, J. Geophys. Res., 106, 28033–28059.

Link:

http://pubs.giss.nasa.gov/docs/2001/2001_Santer_etal.pdf

Thompson, D. W. J., J. J. Kennedy, J. M. Wallace, and P. D. Jones (2008), A large discontinuity in the mid-twentieth century in observed global-mean surface temperature, Nature, 453, 646–650, doi:10.1038/nature06982.

http://www.nature.com/nature/journal/v453/n7195/abs/nature06982.html

Trenberth, K.E., J.M.Caron, D.P.Stepaniak, and S.Worley, (2002), Evolution of El Nino-Southern Oscillation and global atmospheric surface temperatures, J. Geophys. Res., 107 (D8), 4065, doi:10.1029/2000JD000298

http://www.cgd.ucar.edu/cas/papers/2000JD000298.pdf

Wigley, T. M. L. (2000), ENSO, volcanoes, and record-breaking temperatures, Geophysical Res. Lett., 27, 4101–4104.ENSO, volcanoes and record‐breaking temperatures

http://www.agu.org/pubs/crossref/2000/2000GL012159.shtml

COMMON ERRORS IN PAPERS CITED BY FOSTER ET AL

The authors of the papers used different statistical tools and ENSO indices to remove the ENSO signal from Global Temperature and TLT records, and they all failed to account for the multiyear aftereffects of significant El Nino events. This was discussed in detail in my post “Regression Analyses Do Not Capture The Multiyear Aftereffects Of Significant El Nino Events”. That post also appeared at WattsUpWithThat as “Why regression analysis fails to capture the aftereffects of El Nino events.” The post included a detailed discussion of the processes that take place before, during, and after significant El Nino events under the heading “EL NINO OVERVIEW”.

That overview was supplemented by my post “La Nina Events Are Not The Opposite Of El Nino Events.” Briefly, a La Nina event is an exaggeration of ENSO-neutral conditions that occurs when the coupled ocean-atmosphere processes attempt to return to “normal” after a traditional El Nino.

The statistical techniques used in the papers cited by Foster et al also do not address the differences between traditional El Nino events and El Nino Modoki. El Nino Modoki events were discussed in my posts “There Is Nothing New About The El Nino Modoki” and “Comparison of El Nino Modoki Index and NINO3.4 SST Anomalies.”

And the papers that Foster et al cite do not account for “The Reemergence Mechanism,” which should integrate the effects of ENSO events.

ALSO IN PREPRINT RELEASE: THOMPSON ET AL (2009) REPEATS THE ERROR

The 2009 Thompson et al paper “Identifying signatures of natural climate variability in time series of global-mean surface temperature: Methodology and Insights” has been accepted for publication by the Journal of Climate. In it, Thompson et al repeat the errors made by Thompson et al 2008.

http://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175%2F2009JCLI3089.1

Preprint Version:

http://www.atmos.colostate.edu/ao/ThompsonPapers/TWJK_JClimate2009_revised.pdf

Thompson et al were kind enough to post the data that resulted from their analyses for those who like to review findings:

http://www.atmos.colostate.edu/~davet/ThompsonWallaceJonesKennedy/

CLOSING

As long as climate scientists continue to neglect the multiyear aftereffects of significant El Nino events, they will continue to incorrectly conclude, as Foster et al concludes, “the general rise in temperatures over the 2nd half of the 20th century is very likely predominantly due to anthropogenic emissions of greenhouse gases.”