Below are my replications of Figure 4 and Figure 5 of the controversial paper “Influence of the Southern Oscillation on tropospheric temperature” by J. D. McLean, C. R. de Freitas, and R. M. Carter.
Above is the comparison of global atmospheric temperature (RATPAC-A) with the SOI, smoothed with a flat 12 month filter.
Continue reading Replicating McLean
A potential AGW buster, attributing decadal temperature variation largely to internal oceanic effects, ENSO and over the longer term the 1976 Great Pacific Climate Shift, as we did here, is a new paper by Australian John McLean, with New Zealander Chris de Freitas, and
Australian ex-pat Kiwi Bob Carter.
That mean global tropospheric temperature has for the last 50 years fallen and risen in close accord with the SOI of 5â€“7 months earlier shows the potential of natural forcing mechanisms to account for most of the temperature variation.
While the bottom line of this paper is that the change in SOI accounts for 72% of the variance in global temperature for the 29-year-long MSU record and 68% of the variance in global temperature for the longer 50-year RATPAC record, I think the claim of a longer term temperature effect could have been better supported. They stated:
Lean and Rind  stated that anthropogenic warming is more pronounced between 45Â°S and 50Â°N and that no natural process can account for the overall warming trend in global surface temperature. We have shown here that ENSO and the 1976 Great Pacific Climate Shift can account for a large part of the overall warming and the temperature variation in tropical regions.
However, the assertion comes down to Figure 4 where they identify that the mean of the SOI (and temperature) seems to change at 1976. This model is not identified rigorously with any analysis, but is stated as an observation in the text.
Continue reading Influence of the Southern Oscillation on tropospheric temperature
A new page in the “abouts” section lists my non-self-published contributions to discrediting AGW since my transmogrification in 2004 to a skeptic remarkably similar to the one described by LuboÅ¡ Motl in his review of Ralph Alexander’s new book.
Just like a majority of books on the subject, Dr Alexander makes the readers understand that the global warming alarm is almost completely an artifact of manipulation with the human psychology and with the data. But unlike the case of many other books, you will see that Dr Alexander is actually a mainstream scientist (and an applied scientist in the environmental sector) who cares about the good name and functioning of science. Years ago, he was inclined to believe the “general wisdom” about the problem. His diametrically opposite conclusions are a result of his long research of the problem. And his pride of a scientist has been hurt. Climatology has become an ugly example of a scientific discipline that has largely ceased to be scientific.
Also listed are vindications of my POV — bound to provoke some discussion.
The Hon Wilson “Ironbar” Tuckey MP on the ETS. Worth a read. ETS doesn’t have the numbers in the Senate — via Crikey.
Sent: Tue Jul 21 12:58:50 2009
Subject: Emissions Trading Scheme – Confidential
The issue of the arrogance and inexperience of our Leader on the issue of the Emission Trading Scheme has to be addressed.
As a simple example of the negative politics of an ETS has anyone asked why Labor now titles itâ€™s legislation the â€˜Carbon Pollution Reduction Schemeâ€™.
As this note goes to all Members I insist that those who support the ETS should write me a detailed response as to how a Government process of selling certificates to pollute will guarantee that Australia will automatically reduce its emissions. One as versed in business as our Leader knows full well that judgements will be made on the commercial basis of â€œcan I pass this cost onto a captive marketâ€ or â€œshould I run down my existing investment and leave townâ€ for greener pastures such as China, where Government investment is going to achieve the emissions reductions for me, or the USA where the science could be disproved* before their Claytons ETS is implemented and thatâ€™s assuming it can pass the Senate, considering 44 Democrats in the House of Representatives voted against even this Claytons Bill.
Just in case you didnâ€™t know or donâ€™t care, the total vote in the Congress was 431 with the numbers being 219 for and 212 against, so the Bill only passed by 7 votes with 44 Democrats crossing the floor. If the same pattern of voting is followed in the Senate, where the Bill needs 60 votes to advance, and the Democrats have 58 votes, the Bill will be defeated or further diluted.
Another myth is the proposed massive job creation arising from a Derivates Trading Scheme not a Renewable Energy Scheme*. What is more every Green Energy job that cannot reduce the cost of energy is just a further burden to the economy.
There are no amendments to the ETS that will make it work. By its nature, it is either a simple job destroyer or must be so generous as to fail in its purpose.
I can think of no better issue upon which to fight an election be it early or on time.
All that is needed is to differentiate the ETS from the Climate Change response.
I talk to many people and get stopped in the street and in the airport by people who recognise me. Not one has directly raised Climate Change nor do they do so when they are asked to independently list the areas of their concern.
An ETS is a job destroyer and they are worried about that, hence the ACTU 1 million jobs campaign which even Sharryn Burrows canâ€™t make sound convincing.
HON WILSON TUCKEY
The revision of the Copenhagen Synthesis Report was advertised at the ANU Climate Change Institute, directed by Prof. Will Steffen. But they just can’t seem to get it right. The ANU web site refers to Stefan Rahmstorf as Stefan Rahmonstorf.
Ian Castles on the July 5th, 2009 compiled the list of amendments of errors. Below is an update of the current situation.
Continue reading Comedy Synthesis Report
Swanson’s projection for future temperature using presumed regime shifts can be compared with our projection.
The above figure was posted at RealClimate (note this figure is not contained in their paper) with flat temperature intersecting with an extrapolated underlying rate of around 1C/Century seen between 1950 and 1998 at around 2020.
Our projection for temperature, from figure 3 of our paper archived at arXiv and submitted to IJF, Structural break models of climatic regime-shifts: claims and forecasts is based on the current flat rate intersecting with an extrapolated underlying rate of around 0.5C/Century between 1910 and 1976, at around 2050.
Continue reading Swanson's PC Projection
The replication of the highly influential Rahmstorf 2007 A Semi-Empirical Approach to Sea Level Rise, one of the main sources of projected sea level rise, was reported in the previous post.
In a now discredited (and disowned) Rahmstorf et al 2007 publication, Steve McIntyre showed that Rahmstorf had pulled an elaborate stunt on the community by dressing up a simple triangular filter with “singular spectrum analysis” with “embedding dimensions”, I can now report another, perhaps even more spectacular stunt.
His Figure 2 is crucial, as it is where the correlation between the rate of sea level increase, deltaSL, and the global temperature, Temp, is established. If these were not correlated, then there would be no basis for his claims of a significant “acceleration” in the increase in sea level when temperature increases, and his estimates of sea level rise by 2100 would not be nearly so high.
It is well known that smoothing introduces spurious autocorrelations into data that can artificially inflate correlations, and one of the comments on his paper (attached to the first link above) picked up on this. Rahmstorf’s procedure introduces no less than 5 different types of smoothing to produce his Figure 2:
1. singular spectrum analysis – the first EOF
2. he then pads the end of the series with a linear extrapolation of 15 points
3. convolution, (or 15 point filtering)
4. calculates the linear trend from 15 points (on the sea level data only)
5. binning of size 5
I replicated his procedure in the previous post in the series. Here, the entire procedure is substituted with a single binning (averaging each successive M data points). The figure below compares the Rahmstorf procedure at parameters m=13:16 (red line), and the result of binning the same data into bins of size m=13:16 (black line). The sea level data is differenced after binning to get a delta SL.
Continue reading Smooth Operator
RealClimate was so concerned with our paper Structural break models of climatic regime-shifts that they felt compelled to post a paper by Swanson and Tsonis in response ;-), see Warming, interrupted: Much ado about natural variability.
There are a number of similarities and differences. Firstly, ST09 uses a very different method, fitting periodic fluctuations in ocean temperature to spatially distributed data. Regime-shifts are recognized with a measure of coherence between areas, and their theory is that shifts are more likely when synchronized. With this approach, they arrive at major shifts in 1976 as we do, and in 2002, after the big 1998 El Nino.
Using a simple Chow test for structural breaks, we get a break in 1978 and also in 1997, just before the big El Nino. These dates are within bounds of error, and differences in the method, so one might as well say they are consistent.
Continue reading Swanson and Tsonis 2009 on Regime-shifts
Renewable energy is a nice idea, but Peter Lang crunches the numbers and finds solar and wind power are crushingly expensive, do little for greenhouse gas reduction, and are ecologically dangerous. Cap and trade is actually a giant scheme to tax and redistribute, for the benefit of political insiders.
A letter submitted by Peter Lang argues that the numbers prove nuclear power is the only way.
Solar realities: Solar power is uneconomic. The capital cost of solar power would be 25 times more than nuclear power to provide for demand. The minimum power output, not peak or average, is the main factor governing solar power’s economic viability. The least cost solar option would emit 20 times more CO2 (over the full life cycle) and use at least 400 times more land area compared with nuclear Government mandates and subsidies hide the true cost of renewable energy.
Wind realities: Wind power does not avoid significant amounts of greenhouse gas emissions. Wind power is very high cost way to avoid greenhouse gas emissions. Wind power, even with high capacity penetration, can not make a significant contribution to reducing greenhouse gas emissions.
Nuclear power is the least-cost, low-emission electricity generation technology that can provide the large amounts of electricity needed to power modern economies.
Continue reading Renewable Energy Uneconomic and Ecologically Dangerous
Published in Science, this Rahmstorf 2007 article provides a high-end estimate of sea level rise of over a meter by the end of the century (rate of 10mm/yr). Linear extrapolation puts the rate of increase at only 1.4mm and 1.7mm per year depending on start date (1860 or 1950).
The paper was followed by two critical comments, both bashing the statistics, and these are attached to the link above. Rahmstorf replied to those comments. The issues raised are familiar to readers of this, CA, Lucia, and other statistical blogs: significance, autocorrelation, etc. and worth a read.
Worthwhile as the comments are, they do not look into the problem of the end-treatment used by Rahmstorf, and I look at that here.
All of the papers projecting these high end rates, and they all depend on the assumption of recent ‘acceleration’ in sea levels. That is, seem to depend on the rate of increase getting faster and faster.
Rahmstorf 2007 paper uses the smoothing method most recently savaged at CA here, where it was shown despite all the high-falutin’ language to be equivalent to a simple triangular filter of length 2M, padded with M points of slope equal to the last M points. My main concern is that at this crucial end-section, the data has been duplicated by the padding, effectively increasing the number of data points of very high slope.
The figure below shows a replication of the Rahmstorf smoothing with and without padding (moved down for clarity) (code below). Two sea level data sets are shown, one by Church “A 20th century acceleration in global sea level rise” (used in Rahmstorf, data available from CSIRO here) another by Jevrejeva “Recent global sea level acceleration started over 200 years ago?” (data here)
It should be noted this data ends in 2001-2, a truncation bound to maximize recent temperature increases.
Continue reading A semi-empirical approach to sea level rise
Download: Structural break models of climatic regime-shifts: claims and forecasts
Anthony asked if it would be difficult to statistically justify the breaks in temperature between 1976 and 1979 proposed by Quirk (2009) for Australian temperature. He has an interest in oceanographic regime-shifts and climate change. Sure, I said, a simple Chow test.
We ended up rebutting the Easterling & Wehner (2009) claim that describing temperatures since 1998 as declining is ‘cherry picking’, finding a major regime shift occurred in 1997, statistically justifying the use of 1997 as a starting point for temperature trends.
A regime-shift based temperature forecast follows logically from identification of significant breaks. Our paper, “Structural break models of climatic regime-shifts: claims and forecasts“, has been submitted to the International Journal of Forecasting, and is downloadable from arXiv.
Continue reading Preprint on climatic regime shifts
Just for clarity, the influential Rahmstorf 2007 paper that is contradicted by published evidence here, was irrevocably discredited by his own admission here, that apparent increased climate sensitivity was only due to ‘weather’.
In hindsight, the averaging period of 11 years that we used in the 2007 Science paper was too short to determine a robust climate trend. The 2-sigma error of an 11-year trend is about +/- 0.2 ÂºC, i.e. as large as the trend itself. Therefore, an 11-year trend is still strongly affected by interannual variability (i.e. weather).
Its not discredited by the smoothing method necessarily, that involves padding the data series, although padding data series is problematic in a number of ways.
Questions about the validity of the smoothing in Rahmstorf et al 2007 (see CA here for a belly-laugh) invariably turn into questions about how to smooth in general. With so many ways to do it, what is the right or best way?
One aspect of the question is illustrated in the figure below, which is a replication of Rahmstorf 2007 done a few different ways. The blue lines, are the trends using singular spectrum analysis (SSA) with embedding periods of m=11 (dashed) and m=14 (solid) respectively, and the minimum roughness criterion (MRC). Embedding period makes some difference. The red lines, however, are the result of applying ssa without MRC. This makes a bigger difference. (The smooths are translated for readability).
Continue reading Rahmstorf 2007 Discredited