Both the United States and Australia have pending carbon cap-and-trade legislation. While not a political blog, this mechanism is intrinsically numeric in its relationship to regulating carbon, so within scope.
CommentsAppearing in Energy and Environment (ee-20-4_7-stockwell2) is a note by myself on a paper by IPCC lead authors Rahmstorf, S., Cazenave A., Church J.A., Hansen J.E., Keeling R.F., Parker D.E., and R.C.J. Somerville, Recent climate observations compared to projections published in Science in 2007.
As shown by 102 citations in Google Scholar already, Rahmstorf et al 2007 has been one of the main references for alarmist calls to action because the “climate system is responding more quickly than the climate models indicate”. Taking the first one off Google:
The strong trends in climate change already evident, the likelihood of further changes occurring, and the increasing scale of potential climate impacts give urgency to addressing agricultural adaptation more coherently. There are …
Adapting agriculture to climate change – pnas.org, SM Howden, JF Soussana, FN Tubiello, N Chhetri, M … Proceedings of the National Academy of Sciences, 2007 – National Acad Sciences.
Respected on-line authors like Peter Gallagher, Mark Lawson and Lucia were concerned with the paper. Lucia attacked the ’slide and eyeball’ approach. I engaged with Rahmstorf at RealClimate and wrote a number of articles on the uncertainty, until he told me in effect to ’sod off and publish’. But rather than try to diagnose a sloppy methodology and be ignored, time and evidence has done the job instead. Here is my abstract.
Abstract: The non-linear trend in Rahmstorf et al. [2007] is updated with recent global temperature data. The evidence does not support the basis for their claim that the sensitivity of the climate system has been underestimated.
Its gratifying to read that the authors of the Copenhagen Synthesis Report do not seem to agree with Rahmstorf et al 2007 either, in reference to analysis in a figure that ostensibly used the same method as Rahmstorf et al 2007.
Figure 3 … shows the long-term trend of increasing temperature is clear and the trajectory of atmospheric temperature at the Earth’s surface is proceeding within the range of IPCC projections.
Given the way the components of the surface temperature record extracted from the SSA (singular spectrum analysis) line up with various potential causes of climate change in the previous post here, the temptation is to latch onto series 2, and say, aha, there is the forcing due to increase in CO2. It’s the right shape, exponential. Its the right size, about 0.6C.
But looking into fractal data is like seeing pictures in clouds. Be suspicious of magic methods that pull explanations out of the air. Below I have plotted SSA decompositions of the the monthly global temperature anomaly from the HadCRU dataset from 1976 to the present, the period of most recent rise, and attributed largely to GHGs. Kind of zooming in.
Monthly competition to guess the global temperature from the satellite data source RSS has closed.
Results are DOWN by 0.015C to 0.075C. Post to appear soon.
Last month’s results are here, with a number of readers running neck and neck in the prediction game.
< ?php echo file_get_contents("http://landshape.org/poll/pollnet.php/?Q=1ahw&D=RPTU"); ?>
CommentsApplying the singular spectrum analysis (SSA) R package to the global temperature record is potentially insightful. SSA is a type of principal components analysis for time series data, recovering orthogonal components, EOF’s, of different period. Just the ticket for decomposing climate data into potential sources. Although, it must be remembered that temperature series have high enough autocorrelation to produce spurious results in any such method — its not ‘reliable’ in a strict sense.
The code for plotting the non-linear temperature trend, using SSA (singular spectrum analysis) in the figure below is here – ssa-demo. I have made it as turnkey as I can. The steps are:
1. Get and Install package ssa (http://r-forge.r-project.org/projects/ssa/). I had to hand-compile and move the C shared library around so it would find it, not sure why.
2. Run the script below with source(”filename”). Uncomment line indicated after the first time to speed it up. You should get the following replication of the Rahmstorf figure with 11 and 14 embedding period.
Figure 3 of the Synthesis Report of the Copenhagen Congress presents the long-term trend of increasing temperature and the range of IPCC projections.
The sharp-eyed JeanS over at Lucia’s smelt a fish, noticed the trend appeared to be too high, and did a number of replications indicating the window used was 14 years, and not 11 years as claimed in the caption, and also in the list of Figures.
Figure 3: Changes in global average surface air temperature (smoothed over 11 years) relative to 1990. The blue line represents data from Hadley Center (UK Meteorological Office); the red line is GISS (NASA Goddard Institute for Space Studies, USA) data. The broken lines are projections from the IPCC Third Assessment
Report, with the shading indicating the uncertainties around the projections3 (data from 2007 and 2008 added by Rahmstorf, S.).
Figure 3: Changes in global average surface air temperature (smoothed over 11 years) relative to 1990, p. 9
Below is my replication of the figure (using an SSA package in R) with 11 and 14 year periods and the ‘minimum roughness criterion’. The trend lines are displaced by the software, but it makes it easier to see.
ABC interview Just in – You would think the Government would have been more prepared, given Senator Steve Fielding’s simple question: “Where is the direct evidence of CO2 driving up global temperatures?”.
Senator Fielding was accompanied by the Australian “Gang of Four”: David Evans, Stewart Franks, Robert Carter, and William Kininmonth.
Where does the research on greater reliability of ocean temperatures from Steffen come from? Or did he just wing that?
CommentsSenator Fielding has questioned whether carbon dioxide is the bogeyman of the climate world and whether global warming is human induced.
With his Senate vote crucial to the Government’s proposed emissions trading legislation, Senator Fielding spent more than two hours yesterday with Australia’s chief scientist Professor Penny Sackett and the Climate Change Minister Penny Wong.
So has Senator Fielding made up his mind?
He is speaking here with Alexandra Kirk in Canberra.
Read the rest of this entry…
Here is another very useful review paper from arXiv by Indian scientists: Siingh, Gopalakrishnana, Singh, Kamraa, Singh, Panta, Singh, and Singh. Read the rest of this entry…
CommentsThis paper to appear is a very nice review of solar-earth interactions, including atmospheric electricity, by T. Dudok de Wit, J. Watermann.
The Sun provides the main energy input to the terrestrial atmosphere, and yet the impact of solar variability on long-term changes remains a controversial issue. Direct radiative forcing is the most studied mechanism. Other much weaker mechanisms, however, can have a significant leverage, but the underlying physics is often poorly known.
We review the main mechanisms by which solar variability may impact the terrestrial atmosphere, on time scales ranging from days to millennia. This includes radiative forcing, but also the effect of interplanetary perturbations and energetic particle fluxes, all of which are eventually driven by the solar magnetic field.
Three main conclusions for further research are proposed:
Comments