Interannual atmospheric {{CO}}₂ growth rate (CGR), mostly resulting from fluctuating carbon uptake in terrestrial biosphere, is a key determinant of atmospheric {{CO}}₂ concentration. However, CGR observations are merely available in recent decades, which are unable to fully reveal its natural variability and interactions with terrestrial ecosystems and climatic drivers. Here we present a reconstruction of interannual CGR over the past nine centuries (1100-2006) based on a globally distributed temperature-sensitive proxy network. The reconstruction is validated by the comparison with dynamic global vegetation model simulations and the El Niño-Southern Oscillation. Our data reveal a close association of CGR variability with atmospheric {{CO}}₂ concentration and tropical climate. Present CGR variability is unprecedentedly high over the past nine centuries, suggestive of the instability of present carbon cycle and the reducing resilience of atmospheric carbon balance under intensifying anthropogenic forcing. Our record provides a pre-industrial constraint for perceiving the climate-carbon coupling under historical climate forcings. The atmospheric carbon growth rate is poorly constrained beyond the modern era. This study presents a reconstruction of the interannual atmospheric carbon growth rate over the past nine centuries, revealing long-term carbon-climate interactions and variability.
Zhang et al. (Mon,) studied this question.