Tag Archives : Rahmstorf

Errors of Global Warming Effects Modeling 32

Since 2006, in between promoting numeracy in education, and examples of simple statistics using topical issues from the theory of Anthropogenic Global Warming (AGW) to illustrate points, I asked the question “Have these models been validated?”, in blog posts and occasionally submissions to journals. This post summarizes these efforts. Species Extinctions Predictions of massive species […]

Jan Pompe Science Project 37

Some time ago I had a brief discussion with Leif Svalgaard on ClimateAudit blog inspired by an exchange between Leif and David Archibald when the latter complained that Leif’s TSI reconstruction was “too flat”. The sunspots exhibited cyclic variability in terms of the frequency of the cycles and that most thermostats work by pulse width […]

Nir Shaviv 40

The theory of this Israeli astrophysicist has gained traction as the great white hope of climate skeptics. Below are some sources of background reading. Shaviv champions the solar-wind modulated cosmic ray flux (CRF) hypothesis, which was suggested by Ney, discussed by Dickenson, and furthered by Svensmark (see CO2 Science). Evidence consistes of correlations between CRF […]

Climate Flagship Response 3

A number of familiar tests, often used to evaluate the performance of models: R2 correlation, Nash-Sutcliffe efficiency and similarity of trends and return period, were reported here, noting not much evidence of skill in the DECR models compared with observations at any of these. I also said what a better treatment might entail but left […]

Assumptions for linear regression 10

One of the main assumptions of linear regression is, ahem, linearity. Here is an example drawn from dendroclimatology, the reconstruction of past climates using tree rings, of the trouble one can get into by blindly assuming linearity. This subject was dealt with some time ago at ClimateAudit Upside-Down Quadratic Proxy Response. From the Summary of […]

Rahmstorf Revisited 7

The sharp-eyed UC who keeps a good technical blog on signal theory alerted me to this intelligent reference in the Finnish media to Rahmstorf et al. 2007. This is a paper I have reviewed previously and had words with Stefan at RealClimate demonstrating they had grossly underestimated the uncertainty at the end points. This flawed […]

Rahmstorf 7 Finale 32

“According to a new U.N. report, the global warming outlook is much worse than originally predicted. Which is pretty bad when they originally predicted it would destroy the planet.” –Jay Leno If ever there was a good example of alarmists views being given a free ride by a major journal, then the publication in Science […]

Examples of simple smoothers

How much error is there in smoothed climatic and financial series? How much does variability at the ends of the series affect the trend as a result? Here we showed that certain ways of treating the end points introduce a lot of variability. Here we show in certain smoothers variability at the ends can affect […]

Rahmstorf et al. 2007 Update 8

Well it is almost 24 hours since I posted the comment below to RealClimate at the post by Stefan Rahmstorf, about the inconsistency in the methodology used in their Science Brevia article to show that climate is trending higher than IPCC models. As yet the post has not appeared. I can’t see how it breeches […]

Confidence Limits of Minimum Roughness Criterion 17

Here I show more humorous effects of smoothed trend lines with the ‘minimum roughness condition’ (MRC). The confidence limits blow out. Fitting a straight line to data such as global temperature data is a common linear regression example problem. Linear regression of stock prices tells you your rate of appreciation. Smoothing, (or filtering) is used […]

Rahmstorf et al. 2007 IPCC Error? 52

There appears to be an error in the influential paper by Rahmstorf et al. (2007). Rahmstorf et.al. (Science Brevia, 4 May 2007, p709 [1]) reports that the trend of the global mean of surface temperature and sea level raise concerns that the climate system “may be responding more quickly to climate change than our current […]