It is a concise and very useful compilation of the data, but on one point they have taken a very conservative stand. One of the most reported findings in both the mass and social media was that the carbon dioxide (CO2) concentration of the atmosphere had risen to around 390 parts per million in 2011, a level unprecedented in the past 800,000 years. Given the new available evidence, that should be 15 million years.

That's right, CO levels have not been as high today in the last 15 million years!!

The report is right in saying that DIRECT evidence (from analysing atmospheric bubbles trapped in Antarctic ice cores, drilled down to ice 800,000 year old) only goes back that far. But new research from the paleoclimate record using proxy data allow estimation back much further.

The evidence is presented in a research paper in 'Science' in October 2009 by Aradhna Tripati at UCLA and colleagues, entitled  Coupling of CO2 and Ice Sheet Stability Over Major Climate Transitions of the Last 20 Million Years.

Here is the article incorrectly saying CO2 levels are the highest in 800,000 years rather than correctly saying the highest in 15 million years.

Atmospheric CO2 levels hit 800,000-year high: CSIRO