View Full Version : The story of the ice cores
2008-Jan-13, 09:50 PM
One of the main incentives to the global warming hype was the analysis of the ice cores of Greenland in which 'water' isotope variation (dD, d18O) is interpreted as temperature variation for instance Alley 2000 (http://www.ncdc.noaa.gov/paleo/pubs/alley2000/alley2000.html) because if the temperature changes the isotope ratios change. This line of reasoning is an affirming the consequent fallacy, A -> B hence B -> A which fails if also C -> A.
I became sceptical of this interpretation with the discovery of several Mammoth mummies far in North Siberia who had lived there on a productive grassy steppe in the alleged coldest periods i.c. Younger Dryas, suggesting that it warmer than today. This just could not be.
I have worked for several years on this but I think I have solid evidence that the ice core interpretation is wrong. They do not tell about temperature exclusively but also about aridity and you can't use evidence twice. If a spike is all about moisture change, it can't be about temperature change simultaneously.
The Younger Dryas was not notably colder than the preceding or successing period but it was hyper arid. That explains the isotope spike, wrongly interpreted as temperature change.
hypothesis first or evidence first?
I'm really no expert on this (or anything else for that matter), but I think it would be a good thing if some more skeptical people looked at the original assumptions, for a start. Any subsequent interpretation depends on those assumptions being reasonably valid.
How are we so sure that the ice core air bubbles have been truly closed with respect to CO2 content over geological time? OK this is a bit of a separate issue to the one you mentioned, but it all feeds in.
As to the D/P isotope ratio and temperature versus aridity issue. As I understand it, the ratio depends on the temperature of evaporation from the oceans. It should not matter what the precipitation rate at a particular location is. That precipitation, of however much or little, should carry the D/P signature of the temperature at which it evaporated.
I guess there would be a second fractionation opportunity when the vapour condenses to form precipitation. I don't know if they account for this in the calculations.
2008-Jan-14, 01:35 PM
Of course this is a rather complex matter, balancing between basic physics, empirical findings and geologic/hydrologic evidence. We would be talking about dD d18O, deuterium excess, meteoric water lines on one hand, see chap-1 (http://www.science.uottawa.ca/~eih/ch1/ch1.htm), chap-2 (http://www.science.uottawa.ca/~eih/ch1/ch2.htm), chap-3 (http://www.science.uottawa.ca/~eih/ch1/ch3.htm),
An important element is:
Vapour generated under low humidity conditions has a high deuterium excess
On the other side of the equation, empiric evidence, we find this very interesting publication: Anomalously mild Younger Dryas summer conditions in southern Greenland. (http://www.geol.lu.se/personal/seb/Geology.pdf.pdf) versus
this fundamental study. (http://www.ipsl.jussieu.fr/GLACIO/hoffmann/Texts/jouzelJGR1997.pdf). Pay especially attention to para 4.3:
next we put the pieces together.
Reading the "fundamental study", it seems the temperature of precipitation is given the most importance.
All I can say is, I have for several years trying to find literature on H2O and THO fractionation on distillation at sub-boiling temperatures. Good grief what a complicated topic.
Yes I have papers in which vapour has been instantaneously removed from liquid containers by a dry gas stream and analysed, hence giving the evaporation ratio at that temperature.
However in the real world there is water vapour in the atmosphere, and of course if you are doing a distillation there is vapour in the vessel, so it kind of re-equilibrates.
In the end, the only way of getting this information for your own lab set up is to do the experiments yourself, so it's a kind of empirical fudge factor.
2008-Jan-15, 03:30 PM
There is one essential thing overlooked in all those publications. hint: try finding the term "dew point" or perhaps "dewpoint". And think what the relation is between relative humidity and dew point.
Sorry outmaxed right now, getting back later.
2008-Jan-23, 11:40 PM
I did some amazing discovering pertaining to the first carbon dates during the last glacial transition in the time of the roller coaster ride of the ice core isotopes. The transition from the Bolling Allerod period to the Younger Dryas is thought to have been a time of intense cooling. But there is a definite mismatch between paleo botany and isotopes. if we unexplain the cold warm explanation of the isotopes, not only in the ice cores but wide spread around the Atlantic and we substitute wet - arid then all of a sudden everything makes sense.
So I decided to go and prioritize on writing the paper.
1.Establishing the BA - YD transition robustly on 12,660 Calendar years BP (NOT 12,900) based on five independently counted high resolution records (GRIP, NGRIP ice cores, Meerfelder maar, Ammersee and lake Gosziac (Poland)continuous varves counts, all agreeing very closely. I may find more.
2. Testing the carbon dated paleo botanic record against this boundary and make a major discovery, the mismatch started already in 1950 with Libby et al.
3. discuss that this disqualifies the temperature interpetation of the isotopes in the ice cores
4. Explain why the moist arid transition is consistent with the isotope depletion.
Pre peer reviewers are highly desired.
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