/sci/ - Science & Math

Another fact:
The increase in CO2 coincides with a reduction of the ratio of C-13 to C-12 in the atmosphere.
The ratio of C-13 to C-12 in fossil fuels is lower than in the atmosphere. Burning fossil fuels creates CO2 that has less C-13 than the atmosphere.
Any explanation that the increase is not caused by humans burning fossil fuels would need to explain that observation.

>>14670761
Confirmation that rising carbon dioxide levels are due to human activity comes from analysing the types of carbon found in the air. The carbon atom has several different isotopes (eg - different number of neutrons). Carbon 12 has 6 neutrons, carbon 13 has 7 neutrons. Plants have a lower C13/C12 ratio than in the atmosphere. If rising atmospheric CO2 comes fossil fuels, the C13/C12 should be falling. Indeed this is what is occuring (Ghosh & Brand 2003) and the trend correlates with the trend in global emissions.
Picrel: Annual global CO2 emissions from fossil fuel burning and cement manufacture in GtC yr–1 (black), annual averages of the 13C/12C ratio measured in atmospheric CO2 at Mauna Loa from 1981 to 2002 (red)

Causation is causation.

>>6457734
http://www.bgc.mpg.de/service/iso_gas_lab/publications/PG_WB_IJMS.pdf

Additional confirmation that rising CO2 levels are due to human activity comes from examining the ratio of carbon isotopes found in the atmosphere. Carbon 12 has 6 neutrons, carbon 13 has 7 neutrons. Plants have a lower C13/C12 ratio than in the atmosphere. If rising atmospheric CO2 comes from fossil fuels, the C13/C12 should be falling. Indeed this is what is occurring . The C13/C12 ratio correlates with the trend in global emissions.