Environmental precursors to rapid light carbon injection at the Palaeocene/Eocene boundary

The Palaeocene/Eocene thermal maximum — a period of intense global warming about 55 million years ago — was associated with a massive release of isotopically distinctive greenhouse gases into the ocean-atmosphere system. It remains unclear, however, whether this input caused or resulted from the global warming and environmental change that characterize the event. Sluijs et al. use high-resolution records of environmental change across the Palaeocene/Eocene boundary from two sediment sections in New Jersey to shed light on this question. They find that the onset of environmental change and surface-ocean warming preceded the input of greenhouse gases by several thousand years at this location. This sequence of events is consistent with the proposal that deep-ocean warming caused the dissociation of submarine gas hydrates, releasing massive amounts of the greenhouse gas methane. But the cause of the early warming remains uncertain.