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AG, it does NOT confirm anything regarding global climate trends at this temporal resolution! The Vostok ice core is in Antarctica; it is not a global temperature record. The only way that you can have a global temperature record from regional proxy data is to create a combined/merged data set. That's the issue with these various analyses. If you look at the figure I posted, you can see that the Esper curve, which is only for tree-ring data in the Northern Hemisphere, is much noisier than the merged datasets from the other groups. Furthermore, continental Antarctica is actually cooling, whilst the Antarctic Peninsula, the coast, and the adjacent ocean waters are warming. That in part explains why the rise at the end of the Vostok record is not as dramatic as the instrumental surface data which appears at the end of the figure above. Finally, Vostok ice core proxy temperatures are based on the 18O/16O ratio in precipitation, which does not respond immediately to global temperature changes (the effect on the ratio has to propagate through the atmosphere and ultimately effect the isotopic composition of the water vapor that becomes rain, snow, and ice).

This mistake is made over and over and over again, and it's one of the ways that the "hockey stick" critics have tried to assess his data. Regional temperature variability is always going to be greater than a merged data set, because the peaks in one region may be partially or completely canceled by troughs in another region.

However, note something: the location of the warm and cold periods still generally coincides with the other records. The only point of dispute regards the magnitude of the warmest peaks around 400 and 900-1000 AD compared to the end of the ice core record.

By the way, at what year exactly is the Vostok ice core temperature record considered to end?

"The second graph (Data 3) is for the past 200 years. This time period includes all of the Industrial Revolution which began in the mid-1800s. The start of the Industrial Revolution marked the beginning of the large-scale exploitation of fossil fuels. The small dip in temperature in the early 1800s was caused by volcanic eruptions which reduced the amount of sunlight reaching the Earth's surface. CO2 inflection points are visible at around 1860, 1950 and 1975. After 1958, the data are from annual air measurements, not ice core proxies, and are therefore of higher quality."

So if this is correct, then in your plot the temperature data only goes to 1958. In which case the temperature rise over the last 40 years, which would increase the endpoint of your graph by at least 0.25 C, isn't shown.

It's useful to look at Vostok data over 400,000+ years, because on that scale what happens in 500-1000 years is integrated by the climate system into the precipitation signal. But in the modern timeframe, the Antarctic is partially decoupled from processes happening in the rest of the world.

As a final aside, Mann's multi-proxy data record includes six ice-core records, but does not include the Vostok ice core data. I have no idea if Vostok was excluded because of what I said above, or for other reasons.