This article summarizes recent patterns and mechanisms of carbon exchange by terrestrial ecosystems. It highlights that terrestrial ecosystems have been absorbing a significant portion of the carbon dioxide emitted by fossil fuel combustion, with the terrestrial biosphere being largely neutral in the 1980s but becoming a net carbon sink in the 1990s, primarily in northern extratropical regions. The sink is roughly split between North America and Eurasia, while tropical land areas were approximately in balance, implying a carbon sink that offset emissions due to tropical deforestation. The evolution of the terrestrial carbon sink is influenced by changes in land use, such as regrowth on abandoned agricultural land and fire prevention, as well as responses to environmental changes like longer growing seasons and fertilization by carbon dioxide and nitrogen. However, uncertainties remain regarding the magnitude of the sink in different regions and the contribution of different processes. Atmospheric observations of CO₂ and O₂ concentrations allow for the partitioning of atmospheric CO₂ uptake between land and ocean. Global carbon budgets, updated in the most recent IPCC assessment, show a net terrestrial biospheric flux of about -0.2 Gt C yr⁻¹ in the 1980s and -1.4 Gt C yr⁻¹ in the 1990s. Land-use change estimates suggest emissions in the range of +0.6 to +2.5 Gt C yr⁻¹ for the 1980s, largely from deforestation in the tropics. Spatial patterns show that extratropical Northern Hemisphere land areas contribute significantly to the global uptake of anthropogenic CO₂. Inverse model results indicate a range of estimates for the northern extratropical net land sink from -0.6 to -2.3 Gt C yr⁻¹ in the 1980s. The partitioning of fluxes between North America and Eurasia remains uncertain, but the mean estimated uptake rates are broadly similar on a per unit land area basis. In the tropics, atmospheric inverse model calculations do not detect the large CO₂ source expected from deforestation alone, but show variable results clustering around zero, implying a sink that balances the deforestation source. However, results are poorly constrained by sparse measurements in the tropics. Interannual variability in the average annual growth in atmospheric CO₂ concentrations is high. Terrestrial metabolism shows large year-to-year variability, influenced by climate factors such as photosynthesis, respiration, nutrient cycling, and fire. The net terrestrial sink appears to have increased from the 1980s to the 1990s, with the unusually large sink in the early 1990s attributed to climate variability rather than a systematic trend. Controls over terrestrial carbon exchange include factors like nitrogen deposition, land management practices, and climate changes. The similarity of fluxes per unit land area or bioclimatic index between North America and Eurasia suggests no asymmetry in uptake processesThis article summarizes recent patterns and mechanisms of carbon exchange by terrestrial ecosystems. It highlights that terrestrial ecosystems have been absorbing a significant portion of the carbon dioxide emitted by fossil fuel combustion, with the terrestrial biosphere being largely neutral in the 1980s but becoming a net carbon sink in the 1990s, primarily in northern extratropical regions. The sink is roughly split between North America and Eurasia, while tropical land areas were approximately in balance, implying a carbon sink that offset emissions due to tropical deforestation. The evolution of the terrestrial carbon sink is influenced by changes in land use, such as regrowth on abandoned agricultural land and fire prevention, as well as responses to environmental changes like longer growing seasons and fertilization by carbon dioxide and nitrogen. However, uncertainties remain regarding the magnitude of the sink in different regions and the contribution of different processes. Atmospheric observations of CO₂ and O₂ concentrations allow for the partitioning of atmospheric CO₂ uptake between land and ocean. Global carbon budgets, updated in the most recent IPCC assessment, show a net terrestrial biospheric flux of about -0.2 Gt C yr⁻¹ in the 1980s and -1.4 Gt C yr⁻¹ in the 1990s. Land-use change estimates suggest emissions in the range of +0.6 to +2.5 Gt C yr⁻¹ for the 1980s, largely from deforestation in the tropics. Spatial patterns show that extratropical Northern Hemisphere land areas contribute significantly to the global uptake of anthropogenic CO₂. Inverse model results indicate a range of estimates for the northern extratropical net land sink from -0.6 to -2.3 Gt C yr⁻¹ in the 1980s. The partitioning of fluxes between North America and Eurasia remains uncertain, but the mean estimated uptake rates are broadly similar on a per unit land area basis. In the tropics, atmospheric inverse model calculations do not detect the large CO₂ source expected from deforestation alone, but show variable results clustering around zero, implying a sink that balances the deforestation source. However, results are poorly constrained by sparse measurements in the tropics. Interannual variability in the average annual growth in atmospheric CO₂ concentrations is high. Terrestrial metabolism shows large year-to-year variability, influenced by climate factors such as photosynthesis, respiration, nutrient cycling, and fire. The net terrestrial sink appears to have increased from the 1980s to the 1990s, with the unusually large sink in the early 1990s attributed to climate variability rather than a systematic trend. Controls over terrestrial carbon exchange include factors like nitrogen deposition, land management practices, and climate changes. The similarity of fluxes per unit land area or bioclimatic index between North America and Eurasia suggests no asymmetry in uptake processes