An objective analysis of the evidence for global warming suggests little if any anthropogenic effect, consistent with a direct radiative effect from increased CO2. It is also obvious that global temperature and ocean heat content should be related, so it's somewhat surprising to see OHC rising so fast around 2002-3 when ocean temperature is relatively stable (upper line below).
Also given the known issues with this data set, it's bizarre to see top bureaucrats and scientists like Wong/Steffen Read more [...] 17 com
Here, out-of-sample tests are used to test the robustness of the linear regression models of natural variation in global temperature. Previous models were developed on the whole data set. Here we develop them on partial data sets and examine how well they predict temperatures on the other part. These are also called independent tests.
The models that do well on the unseen data are in some sense more robust, reliable, and it gives you a feel for the constraints the data are placing on the models. Read more [...] 11 com
To continue our excursion into natural variation models of global temperature: What do they predict?
Here are a couple of different models fit with data up to the year 1990. This was in order to compare their projections with out-of-sample reality after 1990. The year 1990 is also the start of the major IPCC projections from the TAR WG1 available here.
The upper panel shows the entire HadCRUT global temperature in black up to 1990, the linear models are in red, while the IPCC projections Read more [...] 19 com
One simple way to separate the influence of humans from natural variation is to fit a simple linear regression containing sinusoidal terms, as shown in previous posts.
The figure below shows the result: linear (dotted red), periodic (dashed red) and their sum (solid red) applied to global temperature data sets (A) GISS and (B) HadCRUT and (C) to a selection of simulation models.
Two sinusoidals of period 21 and 63 years were used, but the phase, or start and end points, were not determined. Read more [...] 44 com
Below is quick review of some of the evidence and consequences of a 60 year climate cycle. According to Roy Spencer, the argument that increasing carbon dioxide concentrations alone are sufficient to explain global warming is reasoning in a circle. By ignoring natural variability, they end up claiming that natural variability is insufficient.
However, the recent paper by Craig Loehle finds only a very small linear warming trend is left (potentially attributable to AGW) after subtracting the 60â€“70 Read more [...] 12 com
In tests of the rigor of the Steffen/Wong statement that "not only is the OHC increasing, it is increasing faster", we previously used a linear regression model including natural cycles. The question was raised about the confounding of an upward trend with part of the quadratic terms representing 'acceleration'. This risk is increased by the short run of data (only 54 years) and also because the phase of the periodic terms is a free variable. The periodic is free because both sin() and cos() Read more [...] 29 com
Code and figures to quantify the answer to the question "Is ocean heat content is accelerating?" are below. The idea is that 'acceleration' is synonymous with the significance of a quadratic term in a regression:
1. Annual OHC data from NODC.
2. Fit a regression model (M1) incorporating linear and periodic terms of period 60 years (to account for Pacific Decadal Oscillation):
M1 = lm(OHC~x+sin(f)+cos(f))
3. Fit another regression model with the addition of a quadratic Read more [...] 81 com
Innovation is not dead as Dyson eliminates the fan (maybe there is one inside though), showing the power of careful attention to shape.
Rational policy analysis is not an oxymoron, as Peter Gallagher deconstructs the emissions trading scheme (ETS).
John Robb suggests we are living in Extremistan:
That's Nassim Taleb's term to describe areas of our experience that defy statistical analysis, modeling and thereby prediction. Essentially, he makes the persuasive case that all of the topics covered Read more [...] one
We'll be watching the drop in ocean heat content (OHC) raised by the brilliant Bob Tisdale for a potential follow-up to the Recent Climate Observations: Disagreement With Projections paper, where observations disproved speculations.
To some, the OHC represents a change in alarmist direction that became evident at as a result of due diligence activities of Senator Fielding and the Minister for the Climate Change and Water, Penny Wong. According to Penny Nova,
the alarmists have abandoned air temperatures Read more [...] 40 com
My comments on the topical 'Yamal' issue:
My AIG article demonstrating reconstruction of a hockey stick with red noise, neatly illustrated the possibility of circular reasoning in screening trees by their response to temperature. Around 20% of random series (or 40% if you count the inverted ones) correlate significantly with the temperature instrument record of the last 150 years, and when averaged back beyond the present create the straight handle of the stick.
While this was obvious to many, Read more [...] none
This numeracy exercise for schools can be adapted to grades pre-up. You need:
1. A number of strong magnets, at least two per group
2. Iron filings
3. Selection of nuts of various metals: iron, copper, brass, some lead sinkers.
The hour long exercise is presented as an introduction to scientific thinking in the higher grades. I don't worry about this for lower grades.
I usually choose an assistant to help handing out magnets, though this changes throughout.
1. Discovery - I introduce the magnets Read more [...] one