I found an article that leads the reader to believe that the Earth is currently warmer than it has been at any time in past 600,000 years. The basis for that is a link to the Vostok ice core and a link to some general data sets. The data they are referencing certainly doesn’t support that statement. Here is what the Vostok ice core shows for the past 350,000 years.
The current interglacial has the lowest temperature of the past three. Some of them were shorter, but they were all warmer. The statement that we are warmer now than compared to the other interglacial periods is simply wrong. That doesn’t even include the biggest of the interglacial periods which was finishing up 400,000 years ago. It is normally called the Hoxnian Interglacial. The Vostok ice core does not fully cover that one so I will leave that for another day. To say that the Earth is warmer now than the Hoxnian is absurd.
As for the Holocene Interglacial. I still haven’t put together the new article on the new chart, but I will get to that soon. Since I did have the Vostok data up I put together a quick 12,000 year chart of the Vostok ice core.
This is the raw data (with moving average). By the nature of the Vostok ice core, each data point represents about 20 years of temperature data (by isotope proxy). To me it appears that there is some very natural variation in the data. For the past 10,000 years the standard deviation of the data is 0.67 °C. As there is no real trend in the data over the last 10,000 year period that seems like a reasonable value. The average temperature for the same period is -0.37 °C. So anything within the window of -0.37 +/- 1.34 °C is within two standard deviations of the normal temperature for the past 10,000 years.
Since the average temperature from 1990-2010 is 0.26 °C, that means the average is well within a single standard deviation when compared to the natural variability of the Vostok ice core data for the past 10,000 years. Where does that leave the statement that we are warmer than anytime within the past 600,000 years? I will leave that for you to decide.