A study published in Nature in 2008 reveals that northern ecosystems experience net carbon dioxide losses in response to autumn warming. The research, led by Shilong Piao and colleagues, analyzed atmospheric CO₂ concentration data and ecosystem CO₂ fluxes to assess the impact of autumn warming on carbon balance. The findings indicate that autumn warming leads to earlier carbon dioxide build-up, shortening the net carbon uptake period. This trend is not explained by atmospheric transport alone but is supported by ecosystem flux data, suggesting increased carbon losses in autumn. The study used a process-based terrestrial biosphere model (ORCHIDEE) and satellite vegetation greenness index observations to investigate the seasonal response of northern ecosystems to autumnal warming. Results show that both photosynthesis and respiration increase during autumn warming, but respiration increases more significantly. In contrast, spring warming increases photosynthesis more than respiration. Simulations and observations indicate that northern terrestrial ecosystems may currently lose carbon dioxide in response to autumn warming, with a sensitivity of about 0.2 PgC°C⁻¹, offsetting 90% of the increased carbon dioxide uptake during spring. The study also found that autumn warming has a greater impact on carbon balance than spring warming, with the duration of the net carbon uptake period (CUP) decreasing at nearly all Northern Hemisphere atmospheric CO₂ stations. Eddy-covariance data from 24 northern ecosystem sites confirmed that warmer autumn temperatures lead to earlier CUP ending dates and increased carbon losses. The study highlights that the observed carbon losses in autumn may be offset by increased carbon uptake in spring, but if autumn warming occurs at a faster rate than spring, the ability of northern ecosystems to sequester carbon may be diminished earlier than previously suggested. The study also found that the spatial distribution of the response of carbon flux to temperature, as projected by the ORCHIDEE model, shows that warmer autumns coincide with greater than normal GPP, but due to concurrent stimulation of plant respiration, the geographical area where autumn NPP increases with temperature is much less extensive than the area where GPP increases. The study concludes that the observed carbon losses in autumn may be offset by increased carbon uptake in spring, but if autumn warming occurs at a faster rate than spring, the ability of northern ecosystems to sequester carbon may be diminished earlier than previously suggested. The study emphasizes the need for further research to understand the processes and mechanisms controlling the response of northern ecosystems to climate change.A study published in Nature in 2008 reveals that northern ecosystems experience net carbon dioxide losses in response to autumn warming. The research, led by Shilong Piao and colleagues, analyzed atmospheric CO₂ concentration data and ecosystem CO₂ fluxes to assess the impact of autumn warming on carbon balance. The findings indicate that autumn warming leads to earlier carbon dioxide build-up, shortening the net carbon uptake period. This trend is not explained by atmospheric transport alone but is supported by ecosystem flux data, suggesting increased carbon losses in autumn. The study used a process-based terrestrial biosphere model (ORCHIDEE) and satellite vegetation greenness index observations to investigate the seasonal response of northern ecosystems to autumnal warming. Results show that both photosynthesis and respiration increase during autumn warming, but respiration increases more significantly. In contrast, spring warming increases photosynthesis more than respiration. Simulations and observations indicate that northern terrestrial ecosystems may currently lose carbon dioxide in response to autumn warming, with a sensitivity of about 0.2 PgC°C⁻¹, offsetting 90% of the increased carbon dioxide uptake during spring. The study also found that autumn warming has a greater impact on carbon balance than spring warming, with the duration of the net carbon uptake period (CUP) decreasing at nearly all Northern Hemisphere atmospheric CO₂ stations. Eddy-covariance data from 24 northern ecosystem sites confirmed that warmer autumn temperatures lead to earlier CUP ending dates and increased carbon losses. The study highlights that the observed carbon losses in autumn may be offset by increased carbon uptake in spring, but if autumn warming occurs at a faster rate than spring, the ability of northern ecosystems to sequester carbon may be diminished earlier than previously suggested. The study also found that the spatial distribution of the response of carbon flux to temperature, as projected by the ORCHIDEE model, shows that warmer autumns coincide with greater than normal GPP, but due to concurrent stimulation of plant respiration, the geographical area where autumn NPP increases with temperature is much less extensive than the area where GPP increases. The study concludes that the observed carbon losses in autumn may be offset by increased carbon uptake in spring, but if autumn warming occurs at a faster rate than spring, the ability of northern ecosystems to sequester carbon may be diminished earlier than previously suggested. The study emphasizes the need for further research to understand the processes and mechanisms controlling the response of northern ecosystems to climate change.