Trend Land carbon sink weakening and stagnating

Summary

Since the Industrial Revolution, land and ocean carbon sinks have absorbed about half of human carbon dioxide emissions, greatly slowing warming. Recent carbon-budget assessments, however, show that land uptake excluding direct land-use change has barely grown since around 2000. Carbon fertilization, longer growing seasons and forest regrowth add uptake, while heat, drought, fire, pests, tree mortality, ecosystem degradation and human appropriation of plant productivity erode it. The report judges that although land remains a net sink, it now buffers climate change less reliably than before. It also observes that the more carbon past fertilization has stored, the more could be released later through drought or fire. It therefore cautions that the persistence of a net sink should not be taken as evidence of a healthy and resilient biosphere.