[central_va]

Before fossil fuels:

Ahh. But are CO₂ from natural sources not taken into account? The explosion of Java and Pinatubo did not contribute to the increase

[palmer]

No the lowball figure comes from comparing natural biological CO2 sources with manmade sources. In that case the biological sources are about 20 times manmade. But the biosphere is also a sink and, not coincidentally about the same as the bio source. IOW, man's is all source, very little sink, biological is 50 50. The net annual rise therefore is 100% manmade.

Volcanoes are an asterisk. Pinatubo was equal to a day or two of manmade CO2.