[Moseley]

But the claim that CO2 is increasing in the atmosphere can only date from 1930.

The machine for measuring CO2 in the air was not perfected and put into service until 1930.

So if you claim an increase in CO2 from 1930 to 2019, how meaningful is that?

[palmer]

There are other proxies they don't mention showing thousands of years of lower CO2. Those are inexact just like the ice cores. But they aren't the wrong sign. Another flaw in their argument is that chrmical analysis has been used since 1812: https://journals.sagepub.com/doi/abs/10.1260/095830507780682147?journalCode=eaea

The increase from 1930 to today is more accurate than any of those but is much larger than any increase measured by the old methods. Stomata records have shown up to 60 ppm per century (IIRC) and we will soon have a rate of increase of 60 ppm per 20 years. Also the rise from 1930 must be explained. Can't simply say because prior knowledge is imperfect the current rise could be natural. It requires a explanation. There's a well-supported manmade explanation, and no natural explanation that I have read about.