The article "Recent patterns and mechanisms of carbon exchange by terrestrial ecosystems" by David S. Schimel and colleagues provides an overview of the current understanding of global and regional carbon exchange by terrestrial ecosystems. The terrestrial biosphere was largely neutral with respect to net carbon exchange during the 1980s but became a net carbon sink in the 1990s, primarily due to northern extratropical areas, with North America and Eurasia contributing significantly. Tropical land areas were approximately balanced, offsetting emissions from deforestation. The evolution of the terrestrial carbon sink is attributed to 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, there are significant uncertainties in the magnitude of the sink in different regions and the contribution of various processes. The article also discusses the spatial patterns of carbon uptake, interannual variability, and controls over terrestrial carbon exchange, highlighting the need for improved regional observing systems and data on land-use change and ecosystem processes.The article "Recent patterns and mechanisms of carbon exchange by terrestrial ecosystems" by David S. Schimel and colleagues provides an overview of the current understanding of global and regional carbon exchange by terrestrial ecosystems. The terrestrial biosphere was largely neutral with respect to net carbon exchange during the 1980s but became a net carbon sink in the 1990s, primarily due to northern extratropical areas, with North America and Eurasia contributing significantly. Tropical land areas were approximately balanced, offsetting emissions from deforestation. The evolution of the terrestrial carbon sink is attributed to 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, there are significant uncertainties in the magnitude of the sink in different regions and the contribution of various processes. The article also discusses the spatial patterns of carbon uptake, interannual variability, and controls over terrestrial carbon exchange, highlighting the need for improved regional observing systems and data on land-use change and ecosystem processes.