Over at Real Climate, quite a few of the comments that they post continue to incorrectly interpret the observed behavior of the global average upper ocean heat content changes and sea level rise over the last 5 years (see the misinformation in the comments on the Real Climate weblog More bubkes).
The authors of Real Climate, unfortunately, are permitting this erroneous information (and personal insults) to be posted without their comments and correction. Apparently, the balance provided by Gavin Schmidt that I reported on in my weblog Gavin Schmidt’s Interview On Media Hype On Climate Science Issues was just a fluke.
In this weblog, I will correct two of the major errors made in a number of the comments on the Real Climate website.
One of the commentators on Real Climate list three papers that purportedly refute the finding of no recent upper ocean warming and that the sea level rise has flattened since 2006 . These papers are
Levitus S. et al. (2009) Global ocean heat content 1955–2008 in light of recently revealed instrumentation problems Geophys. Res. Lett. 36, L07608
Cazenave A. et al. (2009) Sea level budget over 2003-2008: A reevaluation from GRACE space gravimetry, satellite altimetry and Argo Glob. Planet. Change 65, 83-88
Leuliette E.W. and Miller L. (2009) Closing the sea level rise budget with altimetry, Argo, and GRACE Geophys Res. Lett. 36, art # L0406
I have already weblogged on two of these papers:
This paper includes the text
“From the results presented in this study, we see that confronting independent estimates of ocean and land contributions to sea level with altimetry results leads to a rather coherent picture for recent years variations. This can be summarized as follows: since 2003, sea level has continued to rise but with a rate (of 2.5 +/-0.4 mm/yr) somewhat reduced compared to the 1993-2003 decade (3.1+/-0.4 mm/yr). “
“The steric sea level estimated from the difference between altimetric (total) sea level and ocean mass displays increase over 2003-2006 and decrease since 2006. On average over the 5 year period (2003-2008), the steric contribution has been small (on the order of 0.3+/-0.15 mm/yr), confirming recent Argo results (this study and Willis et al., 2008).”
On the Levitus et al paper, I weblogged on this in
Even a causal view of the Levitus et al figure, which is reproduced in my weblog, shows that upper ocean heat content has been flat in their data for the last 4 years. The large rise just before than is suspicious (as I am told by colleagues working of this subject), and, moreover, is not consistent with the sea surface temperature trends for this time period (see the GISS data on the ocean surface temperature trends at http://data.giss.nasa.gov/gistemp/2008/Fig2b.gif). Thus even the group that Gavin Schmidt works for (GISS) presents data with no sharp spike that is at all consistent with the Levitus et al analysis and, moreover, the GISS analysis shows that the global average sea surface temperature has been essentially flat since 2002!
All of these analyses are consistent with no significant heating in the upper ocean and a flattening of sea level rise, and even more clearly, that these climate metrics are not “progressing faster than was expected a few years ago”.
Real Climate has it backwards; these climate metrics are changing less than was expected a few years ago!
The Leuliette et al paper states
“An analysis of the steric and ocean mass components of sea level shows that the sea level rise budget for the period January 2004 to December 2007 can be closed…….we find that the sum of steric sea level and the ocean mass component has a trend of 1.5 ± 1.0 mm/a over the period.”
This finding is not flat, but it is not still does not support the claim by Real Climate that this climate metric “is progressing faster than was expected a few years ago”. In fact, this rate of sea level rise is even less than reported in Cazenave et al 2009!
Here is what I propose to Real Climate in an attempt to move to a constructive dialog. I request that they answer these questions:
1. Using the upper ocean heat data from 2004 to the present, what is the Real Climate best estimate of the accumulation of heat in Joules?
2. Using that value of heat accumulation, what is the diagnosed global average radiative imbalance over the time period? How does this compare with Jim Hansen’s value of an imbalance of 0.85 W/m2 for the end of the 1990s?
These are well defined scientific questions. If Real Climate provides clear answers to them, we have moved forward to a more constructive scientific debate. I will keep you posted.