Global Warming - Icecore Data
non-Ice Boreholes

With all the hype, you would think that ice cores and tree rings are the only temperature proxies. Well, NOAA provides borehole data from non-ice sources. There is a great interactive map - just click on the indicated site and then you can see a plot of the data (or download it, your choice). The plots show very clearly that the 1600's were warmer than today in some areas and colder than today in others.

If you want to see the coral data, you will have to plot it yourself. (Excel will do it - copy, past, break data into columns, plot.)

Looking at various data, some of it supports my point of view .. and some dose not. None of it (in the small sample I have looked at) supports the climate change activists. In all cases, the borehole data I have seen disagrees with the tree ring data used to support the IPCC consensus.

Some plots

20,000 Year Borehole Surface Temperature Reconstructions (HPS08) is one of the first non-ice core plots that I made - it absolutely supports the global extent of the Little Ice Age. (Other borehole reconstructions do not.) The data indicates 3 different values of steady state heat flux and 3 different values of thermal diffusivity. Each series (there are nine) is the result of one of the possible combinations.

I like this data set for a number of reasons

20,000 Year Borehole Surface Temperature Reconstructions
Delta Temperature wrt 1961-1990 AD mean of the instrumental record (K)

That said, I have some serious problems with this data


The dataset was created by piecing together 3 separate datasets. This explains why details before the 1500's, like the Younger Dryas and the Roman Warm Period, are not resolved. It also brings into question the calibration of the three datasets with respect to one another. (Yes, I can see the "overlap", and calibration gets almost a full paragraph in the main paper, but I want more!) It is unfortunate that they do not use actual temperature measurements from the surface to the full depth.

To quote a quote

If this is true, then the entire reconstruction is completely bogus. Basically, if the top 100 meters of the column does not represent the climate, then NONE of the column represents the climate. Where do these people think that the temperature anomalies at 200 meters come from? Were these changes able to magically appear without propagating down from the surface? Based on this "quote of a quote", I now want to see the data they have omitted. I suspect that it does not agree with the "official" story about the climate and current temperatures. But, without actually seeing what they are (so obviously) hiding, it is hard to know for sure.

In addition, there is no discussion on how heat flows differently in different rock types. There is no way that granite, limestone, and shale will produce the same diffusion profiles. Yet .. this is not even mentioned.

However, these questions are covered in Climate Reconstruction from Subsurface Temperatures (2000). Basically, the high frequency signal (seen near the surface) encodes data from many sources, but the low frequency signal that finally propagates through the surface layer contains only the long term climate signal. (At least, that is the theory.) This paper is an excellent introduction to the issues.

In summary, I consider the provided data to be interesting, but in serious need of additional review. (This would make a great school project.)


In the papers, and, in fact, anytime borehole temperature reconstructions are discussed, you will see the term inversion. This refers to the mathematical technique used to solve certain matrix equations. Example, from HPS08

Author: Robert Clemenzi
URL: http:// / Global_Warming / Icecore_Data / non-Ice_Boreholes.html