The ice-core record shows a stabilisation of atmospheric CO2
in the 1940s, despite continued emissions from fossil fuel burning and land-use change (LUC). We use up-to-date reconstructions of the CO2
sources and sinks over the 20th century to evaluate whether these capture the CO2
plateau and to test the previously proposed hypothesis. Both strong terrestrial sink, possibly due to LUC not fully accounted for in the records, and enhanced oceanic uptake are necessary to explain this stall.