The Real History of Carbon Dioxide Levels

Greenie Watch ^ | March 23, 2007 | Dr. John Ray

[aruanan]

The older CO2 measurements are thought to be inaccurate due to the scientific instruments used, improper procedures etc.

This is not true. The chemical measurements of atmospheric CO₂ are accurate and they are extremely abundant. The problem is that they gave an unwanted baseline. This is why one of the global warming enthusiasts cherry-picked amongst those numbers to yield a 19th century CO₂ baseline of 280ppm when it was actually much higher. This is also why folks like Jones and Mann in building their chart used ice core CO₂ for preceding centuries and then grafted that (with some hacking to get things lined up) onto Hawaiian CO₂ readings to get a dramatic increase. It's already been demonstrated that ice cores lose a considerable amount of trapped CO₂. This is evident just in comparing 19th and 20th century ice core CO₂ measurements with measurements of atmospheric CO₂ measurements over the same period. The general contours are parallel but the ice-derived measurements are always considerably lower.