Historically inconsistent productivity and respiration fluxes in the global terrestrial carbon cycle

摘要: The terrestrial carbon cycle is a major source of uncertainty in climate projections. Its dominant fluxes, gross primary productivity (GPP), and respiration (in particular soil respiration, RS), are typically estimated from independent satellite-driven models and upscaled in situ measurements, respectively. We combine carbon-cycle flux estimates and partitioning coefficients to show that historical estimates of global GPP and RS are irreconcilable. When we estimate GPP based on RS measurements and some assumptions about RS:GPP ratios, we found the resulted global GPP values (bootstrap mean Pg C yr−1) are significantly higher than most GPP estimates reported in the literature ( Pg C yr−1). Similarly, historical GPP estimates imply a soil respiration flux (RsGPP, bootstrap mean of Pg C yr−1) statistically inconsistent with most published RS values ( Pg C yr−1), although recent, higher, GPP …