Having now submitted a review of the empirical support for weakening of the Walker circulation to the Journal of Geophysical Research, I can get back to the “Is the sea level rise accelerating?” article. The abstract is below:
No Significant Basis for Acceleration in Sea level Rise Last Century
Abstract: Various authors have claimed that sea level rise is accelerating. This assumption is responsible for the high end projections for sea level by the year 2100. We evaluate three main datasets, and two studies, finding no support for an acceleration term in models fit to sea level over the 20th century, and a significant deceleration in satellite altimeter readings from 1993. The only empirical basis for sea-level acceleration arises from the inclusion of data prior to 1900, which cannot be attributed to the influence of greenhouse gases. Moreover, core references for projected sea level rise contain errors and imprecision that bias upward projections for sea level in 2100. We conclude that acceleration of sea level rise both in observations and the projections of climate models cannot be substantiated at this time. We find broad justification and agreement for empirical linear models, greatly reducing CI projections based on linear extrapolation.
Below is the abstract of the manuscript I have been preparing. A draft is available via the contact form above if you are interested in helping out with feedback. Comments from the mysterious Dr Jones that prompted this manuscript are listed below.
Update: Now Submitted to Journal of Geophysical Research.
Recent Data Show No Weakening of the Walker
Circulation
David R.B. Stockwell and Anthony Cox
Abstract: Various authors have examined the strength of the equatorial Pacific overturning known as the Walker Circulation in both climate models and observations, attributing a generalized weakening to anthropogenic global warming. Here we review the analysis in Power and Smith [2007] using updated Southern Oscillation Index (SOI) and NINO sea surface temperature indices. We find no significant long-term changes in the indices, although the SOI appears to have recovered from an anomalously low period from 1976 to 1998. The increasing sea surface temperature in the NINO4 region is not significant, nor representative of other NINO regions. The findings of a weakening Walker circulation appear to be premature, and the corresponding climate model projections cannot be substantiated at this time. The reports of weakening of horizontal atmospheric circulation in climate models should be regarded as an inconsistency and not as an indicator of anthropogenic climate change.
Summary: Mixed El Niño indicators as development slows
The El Niño pattern across the Pacific has not intensified during the past fortnight. Furthermore, the coupling between the ocean and atmosphere which amplifies and maintains El Niño events has so far failed to eventuate. The neutral SOI and sub-surface cooling are evidence of this.
However, the Trade Winds are weakening over a broad area and this may promote renewed warming. In addition, leading climate models continue to predict further development of the El Niño, although not as emphatically as a month or two back. Therefore, the odds remain strongly in favour of 2009 being recognised as an El Niño year.
Dr Jones drew my attention to a paper by Vecchi (2006) that he feels rebuts the view that increased frequency and intensity of El Nino events are responsible for global warming and not increasing greenhouse gases — so I give a quick analysis of it here.
Here is the abstract for our comment submitted to Geophysical Research Letters today. Bob Tisdale is acknowledged as the source of the idea in the first paragraph. Lets see how it goes. If you would like a copy, contact me via the form above.
Comment on “Influence of the Southern Oscillation on tropospheric temperature” by J. D. McLean, C. R. de Freitas, and R. M. Carter
David R.B. Stockwell and Anthony Cox
Abstract
We demonstrate an alternative correlation between the El Nino Southern Oscillation (ENSO) and global temperature variation to that shown by McLean et al. [2009]. We show 52% of the variation in RATPAC-A tropospheric temperature (and 59% of HadCRUT3) is explained by a novel cumulative Southern Oscillation Index (cSOI) term in a simple linear regression model and 65% of RATPAC-A variation (67% of HadCRUT3) when volcanic and solar effect terms are included. We review evidence from physical and statistical research in support of the hypothesis that accumulation of the effects of ENSO can produce natural multi-decadal warming trends. Although it is not possible to reliably determine the relative contribution of anthropogenic forcing and SOI accumulation from multiple regression models due to collinearity, these results suggest a residual accumulation of around 5 ± 1% and up to 9 ± 2% of ENSO-events has contributed to the global temperature trend.
David Appell writes in Scientific American of a number of recent errors in climate science data identified by bloggers, and how, though largely trivial, they are undermining the faith in AGW.
While any error in science is important, and those identified should be swiftly corrected, my concern has always been non-trivial errors of statistics. My beef is that large tranches of AGW orthodoxy are supported by claims that do not pass standard tests of significance. Why is significance important? Wikipedia states that a result is called statistically significant if it is unlikely to have occurred by chance. Therefore many of the claims may be simple change occurrences that scientists are being fooled into believing by their own prejudices. For example:
Last week I prepared a comment defending McLean’s SOI paper. I shall send it in shortly. Basically, I extend their analysis a little and show that the majority of variation in a linear regression model predicting global temperature (not differences) can be accounted for using SOI-related terms.
