Excellent read. This continues and references the Vostok paper mentioned in the NASA reference earlier and extends it another 400,000 years. It shows historical changes in CO2 that range about 120 p.p.m.v from 180 to 300 as normal in the historical record. It shows temperature changes that vary from -9 to +4 C, or a range of 13 C. It attributes these changes to "
. . . hence are a manifestation of the bipolar seesaw19–21 with oceanic and terrestrial processes likely contributing to the reconstructed CO2 variations."
Note that these are not CO2 measurements, they are "
reconstructed CO2 variations" according the scientists involved. Now if you look at the most recent data, the far left of Figure 2, you will see that there are no upward hockey stick graphs. The most recent data is within the normal variation, albeit, at the top of an oscillation. There is absolutely nothing in this paper that indicates anything about man made Climate Change and it shows that both the temperature and CO2 levels have been higher in the past than they are right now, or as close to right now as this research technique allows.
Note that the reconstructed CO2 levels are calculated on a 500 year resolution. This means statistically, that the current real atmospheric CO2 and temperature readings, if they could accurately be compared with this historical record, would have to exists for a significant part of 500 years to show up in this research and if shorter could be missed all together.
We also know from this paper that the research has speculated about 100,000 year and 1,000,000 year natural cycles in CO2 variation, and the paper presents no theory that explains these cycles. We don't know if the chart in Figure 2 for CO2 is a single natural occurring CO2 cycle, the sum of two naturally occurring CO2 cycles (possibility raised in the paper), or the result of the combination of several natural CO2 cycles. Even 800,000 years and the 8 cycles presented are two few cycles to apply wave theory to answer these questions. But, speculating now, it is entirely possible that if CO2 is driven by 3 or 4 independent CO2 processes that cycle at different frequencies, that a 380 or higher CO2 reading could be explained as a perfectly natural variation.
So what is the result. We have something interesting to monitor and research. The smart people should keep studying it, but we need to wait and see because our knowledge is not good enough about global earth process to assume this is the end of the world.
We can't even figure out a way to keep a city from being destroyed by a hurricane or tornado, what makes people think we are destroying the world with our puny little civilizations.