¹⁴C/¹²C -How have scientists used isotopic analysis to determine that the rise of atmospheric CO 2 is mostly from the burning of fossil fuels? A)¹⁴C concentrations are much higher in urban areas than in rural areas,indicating fossil fuels must have a higher ¹⁴C/¹²C ratio than carbon from other sources. B)The decrease in ratios of atmospheric ¹³C and ¹⁴C to ¹²C indicates that the source is fossil fuel carbon. C)Both coal and oil contain a high proportion of ¹⁴C.By analyzing ¹⁴C/¹²C ratios,scientists have been able to determine the source based on this fact. D)Since ¹⁴C is an unstable isotope,scientists have dated the atmospheric carbon to the period since the Industrial Revolution.

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Isotopic analysis has shown that the ratios of atmospheric 13C and 14C to 12C have decreased, indicating that the source of the increase in atmospheric CO2 is from fossil fuels. Fossil fuels are depleted in 13C and have no 14C, which results in a decrease in these ratios in the atmosphere. As fossil fuels are burned, the isotopic signature is transferred to the atmosphere, providing evidence for the anthropogenic contribution to climate change.

14C/12C -How Have Scientists Used Isotopic Analysis to Determine That the That

¹⁴C/¹²C -How Have Scientists Used Isotopic Analysis to Determine That the That