During June 2014 oldbrew published “Explaining(?) abrupt climate change” based on an article published by Judith Curry. The author noticed Antarctica Taylor Dome is mentioned, an interest of the author because of long known highly suspect features of the data for this core and realised the implications of cross checking Antarctica ice cores to a common major event history, in this case with a profound change in timescale. Assuming the high resolution ion data and the low resolution gas data share time, reworking ion data also reworks gas data. The effect of doing this moves CO2 more recent and produces a good CO2 modulation match for the Medeaval Warm Period and Little Ice Age . The IPCC use Taylor Dome as part of the CO2 story. A lot of information has been omitted from the below such as the history over Taylor Dome dating conflicts. The original draft was written a year ago, now been shortened.
The paper behind the above is published Nature Climate Change, “Insights from Antarctica on volcanic forcing during the Common Era” doi:10.1038/nclimate2293. A supplementary file is available containing sufficient information for a reproduction of the critical part.
Figure T1, final result, reproduced with comment later.
Whether this is valid is a matter for discussion.
Figure T2, Reworked data showing the old and new timescales.
Ice cores are infamously a mess on dating regardless of claims by many to the contrary. This certainly applies to Antarctica. The paper is attempting to produce a consistent timeline between all the Antarctica cores, maybe 10 based on common volcanic event markers. This is done in hindsight with access to multiple datasets rather than an attempt to put a timeline on a new data.
One of the cores brought into line is Taylor Dome which is at an unusual location rather close to the ocean (see fig Tx).
The above is a large adjustment and means the ice is much newer than stated in the original publications.
I set about reproducing their result, at least near enough as a confidence check.
Figure T2 is the result, near enough for my purposes and included resampling to regular.
This is the scheme I used, crude but works. No attempt was made to handle curvature, which seems minimal over the period of interest.
Figure T4, annual data plot
There is another ion data concurrent with the Sulphur used for the volcanic eruption work. Figure T4 includes Na. Sodium. I was surprised to see a major peak very close to AD1540. This is a curiosity at a near ocean Antarctica site.
Any connection with a European event seems far fetched but if any readers have information on a global event this would be novel. It also presupposes remarkable timing accuracy which I rather doubt.
The matter of Taylor Dome carbon dioxide proxy as used by IPCC justification of human influence
Taylor Dome is also critical to IPCC assertions
The above remarkably vague plot is of a critical claim about history. The new work on an allied data shows the timeline in error. I think major timing error was at least suspected when the ice core original work was done, moreover other works shortly afterwards all point to error. This does not seem to have been addressed.
Also available as a PDF (2.5MB) and PDF are often as vector plots, indeed so, therefore…
Overlay plot showing the author has accurately identified the dataset used for the IPCC plot.
Figure T7, showing the substantial timing error between IPCC claim and the ion based retiming
Now I overlay this new result on a widely shown plot of estimated temperature.
From PennState archive
Medieval Climatic Optimum
Michael E Mann
Volume 1, The Earth system: physical and chemical dimensions of global environmental change,
Dr Michael C MacCracken and Dr John S Perry
Encyclopedia of Global Environmental Change
(c) John Wiley & Sons, Ltd, Chichester, 2002
A timeline correction places the CO2 trace sensibly aligned with H. H. Lamb’s MWP and LIA, however, I believe little evidence has appeared showing either to be global or affecting Antarctica although recent works suggest there was an LIA effect in Antarctica. However, the absence of a temperature effect at Taylor Dome is unrelated to recording gas values with causal elsewhere, gas being fairly well mixed in the atmosphere.
Paul Homewood has in this December 9, 2014 article saved me the trouble of digging out references. See this blog article.
The Antarctica circumpolar currents tends to equalise coastal climate.
Figure T9 from http://cdiac.ornl.gov/trends/co2/ice_core_co2.html
Figure T9 Courtesy of Warwick University “Antarctic surface currents and surface wind patterns. The surface winds drive the currents (modified from Sugden, 1982).”
Turning to CO2 data for Taylor Dome
First I point out my long familiarity with Taylor Dome data, originally brought by seeing dubious features of the data, improbable.
Ice cores are dubious things especially where structures move/flow as is likely here.
Snow accumulation and compaction follows a power law but this seems to vary with overburden. There is supposed to be a gas pore closeoff point when gas interchange with the atmosphere ceases but this and the effect of gas forming other phases leads to very questionable data as a proxy. I don’t want to get into that argument here.
This law has long struck me as peculiar, a ridiculously close to square law large section of the core. This does tend though to confirm the pore shutoff depth claim of 70 metres. (fit r2 = 0.9995)
Figure T12, as figure T11 but for Ion data, note very extended deep core but also the commonality of shape but also a subtle difference in depth axis. Maybe my mistake.
Figure T13, very top of ion core is peculiarly linear given snow compaction, Sorge’s law. This may be helpful, Bader has many papers
Figure T14, all recent samples on large step, two methods shown, one trivial, the other suppresses noise, same result
Post by Tim