With the smoothing hypothesis there is no way to know if spikes with a duration of a few hundred years or less (like the current spike) can occur naturally by simply looking at the ice core readings.

BCE is before common era and CE is common era. I assume to render the current dating system non christian. “”"

Total political BS; what is “common” about the CE; and just when is To on the CE time scale ?

BP serves the purpose of establishing a time, and a time that is independent of when mohammad fell into a well or whatever.

The Chinese get along just fine without using our calendar or raising a stink about it. This CE/BCE silliness is just a creation of the loony left who want to eliminate human beings and their foibles from the account of history.

BCE is before common era and CE is common era. I assume to render the current dating system non christian.
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Yes. While the terms might sound stilted to those accustomed to BC and AD, I think BCE and CE are specified in most style guides for scientific discussion.

Comparing ice cores with instrument measurements makes no sense. If you smooth the instrument measurements with a 1000+ year running average, then it could begin to make sense. Why, in the ftp link I posted above, is the CO2 in 4050 year old ice only 1700 years old???
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We seem to be looking at different data sets. From the Vostok home page, http://www.ncdc.noaa.gov/paleo/icecore/antarctica/vostok/vostok_data.html, If you go to the CO2 page http://www.ncdc.noaa.gov/paleo/icecore/antarctica/vostok/vostok_co2.html, your data set seems to be the second one listed, referenced to 1987. I used the first data set, referenced to 1999, that seems to be more extensive. All the temperature data I used is from the isotope/temperature page, http://www.ncdc.noaa.gov/paleo/icecore/antarctica/vostok/vostok_isotope.html.

Get it published, excellent stuff. I think many here have long been aware that outgassing of Co2 is a natural process following a rise in T and this supports that position.

I understand the Vostock ice core came from the Antarctic, I would imagine this part of the globe would not show the MWP or LIA due to the large ocean cover in the southern hemisphere and the antarctics self sustaining climate.

I would excercise care though when comparing modern Mauna Loa values with Vostock values, as they cannot be compared. One value is from a cold environment where levels are low due to absorbtion and the other is in an area where the sea would be outgassing Co2 due to warmer SST.

Hence they cannot be compared (though they often are to suggest current Co2 levels are unsual). However, excellent work!
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Thanks. Modern CO2 measurements in Antarctica (http://cdiac.ornl.gov/trends/co2/csiro/csiro-spo.html) do seem comparable to those at Mauna Loa.

“The most recent CO2 determination from the ice-core has a date of about 340 BCE. We can add an early-industrial-era value of 290 ppm at 1800 CE ”

So the line you drew from 340 BCE to 1800 CE was determined by what? It could have been much flatter and then turned up suddenly as in a logarithmic display. Then there is no need to find out why CO2 was so high 5000 years ago, but why it may have accelerated around 1800 CE, which conveniently matches with the industrial revolution.
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The equilibrium model indicates that about 8000 years are required for CO2 to decline in response to a drop in temperature. There might have been a trivial decline in temperature between 340 BC and 1800 AD, so there is no reason to think that temperature caused a significant decline in CO2 during that interval. Between those dates, however, the Romans paved and cemented their way through much of Europe and the middle-East, the Silk Road was established to China, where the Hans were building a very long wall, Islam spread from Spain to Indonesia, Russia emerged as an organized state, the Incas, Mayas and Aztecs built empires, global trade commenced and intensive agriculture spread to the Americas. All of these things might have shaken a little more CO2 loose from the soil.

I understand the Vostock ice core came from the Antarctic, I would imagine this part of the globe would not show the MWP or LIA due to the large ocean cover in the southern hemisphere and the antarctics self sustaining climate.

I would excercise care though when comparing modern Mauna Loa values with Vostock values, as they cannot be compared. One value is from a cold environment where levels are low due to absorbtion and the other is in an area where the sea would be outgassing Co2 due to warmer SST.

Hence they cannot be compared (though they often are to suggest current Co2 levels are unsual). However, excellent work!

So the line you drew from 340 BCE to 1800 CE was determined by what? It could have been much flatter and then turned up suddenly as in a logarithmic display. Then there is no need to find out why CO2 was so high 5000 years ago, but why it may have accelerated around 1800 CE, which conveniently matches with the industrial revolution.