Unusual characteristics of the carbon cycle during the 2015−2016 El Niño

The 2015−2016 El Niño was one of the strongest on record, but its influence carbon balance is less clear. Using Northern Hemisphere atmospheric CO2 observations, we found both detrended growth rate (CGR) and seasonal-cycle amplitude (SCA) were much higher than that other events. simultaneous high CGR SCA unusual, because our analysis long-term observations at Mauna Loa revealed a significantly negative correlation between SCA. Atmospheric inversions terrestrial ecosystem models indicate strong northern land uptake during spring substantially reduced (or emissions) early autumn, which amplified also resulted in small anomaly annual ecosystems 2015−2016. This autumn primarily due to soil water deficits more litter decomposition caused by enhanced productivity. Our study demonstrates decoupling seasonality cycle over 2015−2016, unprecedented past five decades