Suess effect

The Suess effect, also referred to as the ¹³C Suess effect, is a change in the ratio of the atmospheric concentrations of heavy isotopes of carbon (¹³C and ¹⁴C) by the admixture of large amounts of fossil-fuel derived CO₂, which is depleted in ¹³CO₂ and contains no ¹⁴CO₂. It is named for the Austrian chemist Hans Suess, who noted the influence of this effect on the accuracy of radiocarbon dating. More recently, the Suess effect has been used in studies of climate change. The term originally referred only to dilution of atmospheric ¹⁴CO₂. The concept was later extended to dilution of ¹³CO₂ and to other reservoirs of carbon such as the oceans and soils.

The Suess effect is responsible for the dilution of atmospheric ¹⁴CO₂ created during the Bomb pulse to levels similar to those in the early 1950s. This creates problems of dating of recent organic material, which has now radiocarbon levels similar to those present in the pre-industrial atmosphere.