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 extinctions due to AGW came into prominence with a January 2004 paper in Nature called Extinction Risk from Climate Read more [...] 25 com
The rumbling Alaskan volcano Redoubt has exploded producing a stratosphere-reaching plume in excess of 60,000 ft (17 km). An eruption is termed 'ultraplinian' if its ejecta reaches the stratosphere, about 10km in height. Dust and gases in the stratosphere are known to depress the global temperature for up to a few years after the eruption. The extent of cooling depends on the amount and type of material, the size and duration of ultraplinian eruption, and the latitude (high latitude eruptions Read more [...] 6 com
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 that for another time: The percentage of droughted area appears to be a ’bounded extreme value, peaks over threshold’ or bounded POT statistic. The Read more [...] one
Steve McIntyre, always gracious in his acknowledgments, mentioned my note in the Australian Institute of Geologists newsletter (AIG News No 83 Mar 2006 pp14) in a post yesterday "The Full Network". We've discussed on many occasions that you can "get" a HS merely from picking upward-trending series from networks of red noise (David Stockwell had a good note on this phenomenon on his blog a couple of years ago. My first experiments of this type were on the cherry picks in the original Jacoby network.) Read more [...] 65 com
How many narcissists does it take to change a light bulb? Just one -- but he has to wait for the whole world to revolve around him. Blog watchers would have noticed a post at ClimateAudit where Steve has reprinted a comment by Ian Jolliffe on the form of PCA (decentered) used way back in 1998 by Mann et al. in the original hockey stick papers. (If you don't understand all that you have some background reading at CA for homework.) In a numerate science, statistical methods are standard, commonly Read more [...] 14 com
Here is a summary of the chapters in my upcoming book Niche Modeling to be published by CRC Press. Many of the topics have been introduced as posts on the blog. My deepest thanks to everyone who has commented and so helped in the refinement of ideas, and particularly in providing motivation and focus. Writing a book is a huge task, much of it a slog, and its not over yet. But I hope to get it to the publishers so it will be available at the end of this year. Here is the dustjacket blurb: Through Read more [...] 4 com
Finally, one journalist has the message right: Duane Freese in his article -- “Hockey Stick Shortened?” -- at TechCentralStation reports on the National Academy of Sciences report "Surface Temperature Reconstructions for the Last 2,000 Years". Repetition of the consensus view of strong evidence of recent global warming is not newsworthy. Increase in the uncertainty of the Millennial temperature record is. He says: The most gratifying thing about the National Academy of Science panel Read more [...] 14 com
Mathematical shapes can affect our lives and the decisions we make. The hockey stick graph describing the earths average temperature over the last millennia has been the subject of a controversial debate over reliability of methods of statistical analysis. From this to this ... The long tail is another new icon, described in a new book, developed in the Blogosphere, by Chris Anderson called "The Long Tail": Forget squeezing millions from a few megahits at the top of the charts. The future Read more [...] 11 com
The Australian Institute of Geoscientists News has published online my article "Reconstruction of past climate using series with red noise" on page 14. Many thanks to Louis Hissink the editor for the rapidity of this publication. It is actually a very interesting newsletter with articles on the IPCC, and a summary of the state of the hockey stick (or hokey stick). There are articles on the K-T boundary controversy and how to set up an exploration company. Reconstructing the hokey stick with random Read more [...] 6 com
In honor of the National Research Council of the National Academies committee to study "Surface Temperature Reconstructions for the Past 1,000-2,000 Years" meeting at this moment, I offer my own climate reconstruction based on the methods blessed by dendroclimatology. The graph below shows reconstructed temperature anomolies over 2000 years, with the surface temperature measurements from 1850 from CRU as black dots, the individual series in blue and the climate reconstruction in black. I think Read more [...] 53 com
The major scientific journals are often regarded as the touchstones of scientific truth. However, their reputation has been tarnished with yet another major scientific fraud unfolding over South Korean researcher Hwang Woo-suk's peer-reviewed and published Stem Cell research. Should the publication of these results be viewed as simple 'mistakes', a crime by a deviant individual, or a broader conspiracy aided by lax reviewing and journal oversight? Blogs were apparently instrumental in uncovering Read more [...] 9 com

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