More Evidence of Climate Stabilization

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1. That last paragraph: Of course.

   I saw that flattish spot in the sea level rise in the graphic in Roger Pielke’s paper. I immediately went to the AR4 to see if I could find any concrete predictions, but they must have just decided that predicting sea level rise is impossible. (I found predictions for thermal expansion rates but not the overall rise.)

   Comment by lucia — April 4, 2008 @ 8:56 pm

2. Lucia, I read the sea height chapter recently too. I thought it was rather measured in their assessment of the data and knowledge. They have an ongoing issue (since at least TAR 2001) with the measured rises exceeding the expected rise calculated from the components, which they attribute largely to instrument bias. This is a perspective that Rahmstorf etal fail to mention, preferring to spin it as ‘contributions rapidly increasing’. Pielke had a discussion about what constituted a contribution or not. Its another big talking point. But irrespective of that, sea levels are actually DECLINING, as I believe the satellite data.

   Comment by admin — April 4, 2008 @ 9:09 pm

3. […] This paper claimed to show that: The data available for the period since 1990 raise concerns that the climate system, in particular sea level, may be responding more quickly to climate change than our current generation of models indicates. By way of recap, this paper figured prominently in the Interim Report of the Garnaut Review where it is clearly used as a source of mainstream scientific opinion: “Developments in mainstream scientific opinion on the relationship between emissions, accumulations and climate outcomes, and the Review’s own work on future business-as-usual global emissions, suggest that the world is moving towards high risks of dangerous climate change more rapidly than has generally been understood.” Interest in the current weather has been growing since people have been observing either sharp declines in temperatures since last year, or relative stability in temperatures over about the last 10 years and wondering how these fit into the picture of global warming. I did some posts putting it into context showing last years temperature drop was not unusual here, that a particular 10 year period has been flat here, and that a number of climate indicators are showing decadal stability here. The Blackboard has been spear-heading rigorous statistical methods for checking IPCC projections and finding post 2001 TAR consistently falsified by climate trends. Contradicting these findings was the paper by Rahmstorf et al 2007, published in Science, by seven of the leading members of the IPCC scientific team. So, I started to audit this paper to see if this paper does in fact provide a more reliable perspective on the issue of whether climate is changing faster or slower than expected. A number of bloggers ‘raised concerns’ about the vague description of the methodology, and argued at Niche Modeling and The Blackboard that there were important sources of uncertainty unaccounted for. Other blogs picked up the issue including Peter Gallagher and Mark Lawson. Stefan Rahmstorf and I exchanged comments at RealClimate.org and here. His main defense was that the end point uncertainty would only affect the last 5 points of the smoothed trend line with an 11 point embedding. Here the global temperatures were smoothed using a complex method called Singular Spectrum Analysis (SSA). I gave examples of SSA and other methods where the end point uncertainty affected virtually ALL points in the smoothed trend line, and particularly more than 5 end points. Stefan clearly had little idea of how SSA worked. His final message, without an argument, was: [Response: If you really think you’d come to a different conclusion with a different analysis method, I suggest you submit it to a journal, like we did. I am unconvinced, though. -stefan] So much for the recap. Keep in mind that the purpose of a scientific exchange like this is to clarify the points of agreement and disagreement and attempt