Lack Of A Trend In The Ocean Surface Temperature Since 2000 – Its Significance

In the Lyman et al 2010 paper [that I have discussed in two posts; see and see], there is the interesting statement that

“…sea surface temperatures have been roughly constant since 2000…”

This finding is based on the section of the paper State of the Climate in 2008 by Peterson and Baringer (2009) titled

Knight, J. et al. Global oceans: do global temperature trends over the last decade falsify climate predictions? Bull. Am. Meteorol. Soc. 90, S56–S57 (2009).

Figure 3.4 top  in this article is presumably the data  that Lyman et al 2010 are referring to. The tropical ocean average anomalies in Figure 3.4 5th figure also shows an absence of further warming since 1998 although, as with the global average, it remains above the long term average (1950 to 2008).

There are important consequences of this lack of a continued global average ocean surface temperature increase:

  • since an increase of atmospheric water vapor is required to amplify the radiative heating from added CO2 and other human inputs of greenhouse gases, the absence of continued ocean surface warming suggests this water vapor feedback to radiative forcing is more muted than predicted by the IPCC multi-decadal model predictions. This more muted response in the real world  is consistent with what has been reported in the study De-Zheng Sun, Yongqiang Yu, and Tao Zhang, 2009: Tropical Water Vapor and Cloud Feedbacks in Climate Models: A Further Assessment Using Coupled Simulations Journal of Climate, Volume 22, Issue 5 (March 2009) pp. 1287–1304.
  • The claims that warming is continuing  (e.g. see) is, therefore, based on the land portion of the surface temperature record  [warm equatorial ocean temperature anomalies in recent years, particularly in the Atlantic, are offset elsewhere in the ocean].  With respect to the land surface temperature trends, we have documented a warm bias as we report in our paper Klotzbach, P.J., R.A. Pielke Sr., R.A. Pielke Jr., J.R. Christy, and R.T. McNider, 2009: An alternative explanation for differential temperature trends at the surface and in the lower troposphere. J. Geophys. Res., 114, D21102, doi:10.1029/2009JD011841.

Of course, as I and others, including Kevin Trenberth, have repeatedly urged (e.g. see and see) we need to move to the use of the ocean heat content change as the metric to assess global warming and cooling. Ocean heat content changes provide a much more robust metric than surface temperature trends as the metric to assess global warming and cooling (e.g. see and see).

A further assessment of the ocean surface temperature trends is available from the excellent website

I have presented two analyses of ocean surface temperature anomalies below; one for mid May 2010 (top) and one for mid May 1997 (bottom). The format has changed and the center point of geography is different (which makes it harder to compare the two figures], but what stands out is not a clear difference in the ocean average, but the remarkably large spatial variations in the anomalies. It is these anomalies that have a much greater effect on the climate that society and the environment experience (e.g. drought, floods, hurricanes, etc) than a global average trend (which has not even been evident for several years).

What is missing from the otherwise excellent website, of course, are time plots of the global average sea surface temperatures, as well as averages for different subregions of the oceans.  With that information, we could more readily track the ocean contribution to the global average surface temperature trend, as well as anomalies within the subregions.

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