it’s usually taken to be the fact that as carbon dioxide concentrations in the atmosphere increase, the 1 per cent of co2 that’s the heavier carbon isotope ratio c13 declines in proportion.
it’s usually taken to be the fact that as carbon dioxide concentrations in the atmosphere increase, the 1 per cent of co2 that’s the heavier carbon isotope ratio c13 declines in proportion.
carbon dioxide in earth's atmosphere:18
the global mean co 2 concentration is currently rising at a rate of approximately 2 ppm/year and accelerating.