Slashdot Mirror

The glaciation records have been published often and openly, and regardless of the level of detail, the only accurate description of the graphs is "chaotic". There was a bit of a fuss a while back about the detection of a regular "signal" with a 30-million-year wavelength, but that took some sophisticated statistical work to ferret out, and is still considered somewhat hypothetical.

You're off by about 3 orders of magnitude. You're confusing putative periodicity of geologic ice ages (maybe every 30-100ma) with glacial oscillations.

We have been in a geologic ice age for about 15 million years. We have had glacial oscillations for the past 3 million years (confusingly also referred to as "ice ages"). The 100ka periodicity is crystal clear. See one of the most highly cited papers in climatology, "Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica", JR Petit, et al., Nature, 1999, figure here.

What's especially funny about this is the claim that the glacial record shows "regular as clockwork" variations. But I suppose this sort of claim is one simple test for whether a writer knows anything at all about the topic. In discussions with scientific quacks,

Your sort of ignorance and arrogance would be laughable if the subject weren't so serious and if you kind of addled thinking wasn't so widespread.

Are you talking about: J R Petit, J Jouzel, D Raynaud, N I Barkov, et al. (1999). Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica. Nature, 399(6735), 429-436. Retrieved April 7, 2009, from ProQuest Medical Library database. (Document ID: 42351682)? Because the phrase is not in there. The paper reads like the researchers were involved in the drilling.

Yeah, that's the paper I originally linked, but you're right- the phrase isn't there. I was at work (with access to the journals) when I wrote that, and had 4-5 of the older Vostok papers open at once. That particular phrase is probably in one of those papers, but I don't have journal access at home (and my cache is empty) so I can't verify that right now. The phrase you're looking for in the paper I did link is below the references, in the Acknowledgements section: "We thank the drillers from the St. Petersburg Mining Institute; the Russian, French and US participants for field work and ice sampling..."

Sorry about the confusion; I was juggling too many papers to keep them all straight on my desktop. But you can also verify that J. Jouzel is referenced many times, with reference 6 being published in 1987 (several years after the section from 950-2083m was extracted in 1982-83), and 12,13 published in 1993 and 1996. C. Genthon is reference 14, published in 1987.

I must humbly disagree that the paper "read like the researchers were involved in the drilling." They've certainly tried to describe the drilling process in a brief manner for the benefit of the reader, but acknowledged the hard work of their fellow scientists, thanked them for their contributions, and provided citations to their original work in extracting and sampling the ice core. It all seems perfectly civilized.

They limited the ice core due to volcanic activity without discussing the impact. None of my editors would allow me to get away with that.

That limitation has exactly the same impact as stopping the drilling above Lake Vostok. It merely truncates the time series, preventing the reconstruction of data earlier than 423,000 years ago. You're probably thinking about studies which fail to sample the population in a uniform or unbiased manner, and thus alter the resulting statistics because they're using a skewed sample. This is a serious problem in many sociological studies, but it's not a relevant concern here. An ice core taken from a shallower hole (like the 3310m core in the paper) has precisely one impact: it provides data back to 423,000 years before the present instead of even further back in time.

The section is clumsily written, almost like they are trying to shove two thesis statements into the same flow. It goes warrant one, warrant two, evidence one, evidence two, synthesis two, synthesis one, closure. Since it is hard to track its flow, the section is a difficult read, which causes the warrant to come across badly, removing support from the general thesis. ... If you want someone to research something, you state 'This study raises these questions for further research' or something similar. Another method is to state 'We suggest... but it would require further research'.

Oh. I thought you were trying to make some kind of point regarding the science. Instead, you were talking about their need for better editing. Heck, you're probably even right. Their writing style probably isn't the same as the articles in your field, and your articles are undoubtedly better written. I concede this point.

That is data analysis and synthesis. I am asking about the appropriateness and validity of the approach, not the data. If a research does not discuss the appropriateness of their approach, then it is impossible to validate the reasons for the approach.

You said "There is no discussion on

What are the problems with the Vostok data?

Diffusion of isotopes over time leads to large horizontal error bars (i.e. it's uncertain when particular temperature/co2 measurements occurred, especially relative to each other). Accumulation rate uncertainty makes these horizontal uncertainties larger at deeper depths (older ages). But vertical uncertainty is smaller (i.e. the absolute maximum of CO2 is less uncertain). Furthermore, the correlation of those values to the global paleoclimate is still a matter of debate, but other ice cores (as well as borehole measurements and coral growth rates) provide measurements that aren't qualitatively different.

What are the bias in the sources you used for the Vostok data interpretation?

That was just a source for the graph, which was produced by Petit et. al. in this article. It's been cited by over 1300 authors according to Google Scholar, so you won't have to look hard to find someone disagreeing with him.

You cover it in a haphazard method. What might be a better strategy is to cover it in clear sections.

Excellent advice... for someone writing a formal research paper. Did I mention I was jotting down a quick Slashdot post instead?

When discussing your expertise, which you brought to the forefront by stating that you are a climate scientist, it might be better stating that you are a grad student working on theoretical and computational physics with work in using gravitational analysis on glaciers.

Brevity is often a virtue. More nuanced explanations such as the one you've proposed ignore the fact that in my previous messages I was only discussing my current project. In earlier years I used other datasets to help correct water storage models such as GLDAS. Glaciers also aren't the main thrust of my research, which is better constraining ocean tide models using satellite gravimetry. It's just that the gravitational signals from the melting glaciers are so large that I have to correct for them otherwise they'd screw up my models. Plus, the quote on the "about me" page was actually "studying physics" that rather than "studing computational and theoretical physics." I think this entire tirade started when you mistook the statement of my interests with my professional field of study, which is more technically a subfield of computational geophysics.

See how annoyingly long and involved that was? I decided to sum those experiences up with the phrase "climate scientist," and I only did it to provide a first hand eyewitness account that the AC had used a "gross generalization" that wasn't true of me or 9/10 of the climate scientists I know. Then I immediately disowned the AC's idea that people should make decisions based on someone's qualifications, and tried desperately to steer the conversation towards the actual science in question. Degrees and titles are irrelevant. All that matters is the quality of the evidence, and the rigor of the analysis behind it.

Negative! There's an alternative building process called cobbing that allows for free-form walls. A group called Cobworks is currently building a cob house in Mexico that's got a number of curved walls.

Curved walls are nowhere near impossible. And placing windows in them is nowhere near impossible either. Furniture and home decoration obviously also has to be bought to fit or placed properly in rooms (i.e. no six foot long paintings hung on a curved wall).

Cordwood is much like the game GO, in that you can learn to do it in a short period of time, but it can take a lifetime to master! Seriously, we are currently designing a home with those thoughts in mind, durability, cost effective, mostly enviromentally friendly.

Cordwood, also known as stackwood, stovewood,etc, is simply softwood (cedar, pine) "fence" posts that are cut to 8" - 16" lengths and laid into a bed of mortar lengthwise. Thus if your logs are 16" inches long, your walls are 16" + thick. This is a highly effective wall adding both thermal mass and good insulation. There are reported cordwood-type structures still standing after 1000 years, and there are many examples in the US that are over 100 years old.

For a pretty geeky look into a cordwood home being built, check out
daycreek.com (2,000 sq Ft, solar collection, doublewalls).

Cordwood houses are unlikely to last as long as stone ones (usually > 500 years) but they rival brick for longevity and cost a fraction of what it costs to build with stone or even brick.

here are some links:

Daycreek Home Page

Cordwood Masonry

Green Home Building...chniques: Cordwood

CORDWOOD - NEWBEE S...pages.com/cordwood

PPR Cordwood - Home