The evolution of large-scale variations in globally averaged atmospheric CO2 concentrations since 1830

Abstract

The analyses of the cumulative sums of the observed yearly averaged atmospheric CO2 concentrations revealed unambiguously two change points during 0–2021. The first abrupt change that occurred during 1830 delineated the starting epoch of the pre-industrial era, which is marked by a linear increase in concentrations (0.24 ± 0.01 ppm/yr.) as described by the IPCC being driven by economic and population growth. Another notable change occurred during 1943 with the start of a uniform acceleration (0.028 ± 0.000 ppm/yr2) since then. These findings bring not only clarity and precision into the IPCC’s vague statement on the topic but also alleviates the bias introduced in estimating the trend (constant velocity) of the atmospheric concentrations, which is three times larger in magnitude (0.78 ± 0.01 ppm/yr.) for the period 1830–2021 if the uniform acceleration since 1943 is not accounted for. If the increased concentrations of CO2 before 1943 are predominantly caused by the climate system, i.e. of non-anthropogenic origin, then the concentrations will continue to increase with the constant velocity estimated in this study despite the efforts to limit the anthropogenic contributions that are the source of the uniform acceleration since 1943.

Keywords

• Climate change
• historical atmospheric CO2 concentrations
• uniform atmospheric CO2 acceleration