[Ouderkirk]

Presently it’s 414 PPM. which translates to 0.04%.

That assumes that NOAA isn’t cooking the books (unlikely) and the real level is likely closer to 300 PPM

[TigersEye]

You're probably right that the NOAA doesn't cook the books on the atmospheric content of CO2 but only because it would be easy for others to check. If they could I think they would.

NOAA Temperature Adjustments Correlate Exactly with the Rise in CO2 - Big Surprise

Thermometers show the US cooling since about 1920, but NOAA massively cools the past to create the appearance of a warming trend. These adjustments make a spectacular hockey stick of data tampering. When plotted against atmospheric CO2, the correlation is almost perfect. NOAA is tampering with the data exactly to match their theory.

NOAA Radiosonde Data Shows No Warming For 58 Years March 7, 2016

NOAA Fiddles With Climate Data To Erase The 15-Year Global Warming ‘Hiatus’ 6/4/2015

National Oceanic and Atmospheric Administration scientists have found a solution to the 15-year “pause” in global warming: They “adjusted” the hiatus in warming out of the temperature record. New climate data by NOAA scientists doubles the warming trend since the late 1990s by adjusting pre-hiatus temperatures downward and inflating temperatures in more recent years.

GISS US tampering.

NOAA = Fake Science!