The Congo Basin contains the largest tropical peatland complex on Earth — roughly 145,000 square kilometers of waterlogged organic matter, much of it thousands of years old. The peat's age has been treated as evidence of its stability. Carbon stored for three millennia is, implicitly, carbon that stays put.
Drake and colleagues measured CO₂ emissions from pristine blackwater lakes within this peatland and found that 40% of the carbon being released is ancient — radiocarbon-dated to approximately 3,000 years old. The lakes are not recycling modern carbon. They are venting carbon that has been sitting in the peat since the late Holocene.
The finding reframes the peatland's carbon budget. The 3,000-year residence time was interpreted as evidence of sequestration — carbon locked away, effectively permanent on policy-relevant timescales. But residence time measures how long something has been present, not how firmly it is held. Carbon that sat undisturbed for millennia is now being mobilized through the same hydrological pathways that have always existed. The lakes function as chimneys: slow, persistent conduits through which ancient carbon escapes the peat and enters the atmosphere.
The distinction between storage duration and stability is easy to conflate and consequential to confuse. Storage duration is a clock — it tells you how long something has been in place. Stability is a force balance — it tells you what would happen if conditions changed. A boulder resting on a ledge for a thousand years is not evidence that the ledge is strong. It is evidence that nothing has pushed the boulder yet. The peat carbon's age proved it had not been mobilized, not that it could not be. The lake emissions demonstrate that mobilization was always occurring, just slowly enough to be invisible against geological timescales. “Stored” and “stable” are different claims requiring different evidence, and treating one as proof of the other mistakes a temporal measurement for a dynamical one.