Unprecedented decline in modern coral reef communities could indicate the onset of the Anthropocene

Coral reefs have experienced widespread and accelerated decline, driven by a combination of global and local anthropogenic stressors. To contextualize these changes, we compared the composition of coral reef communities on Curaçao between 1973 and 2023 with that of corals preserved in fossil reefs from the Last Interglacial period (128–116 ka). These fossil reefs, exposed along the island’s leeward coast, provide a multi-millennial baseline of ecological variability. Here we show that the ecological transformation observed on modern reefs over the past five decades is unmatched when compared to the relatively stable community structure maintained for more than 12,000 years during the Last Interglacial. We propose that the global, rapid, and well-documented collapse of tropical coral reef ecosystems since the mid-20th century represents a stratigraphically relevant signal of anthropogenic change. We surmise that a well-characterized reef site—such as Curaçao—could, in principle, serve as the Global Boundary Stratotype Section and Point (GSSP) marking the onset of the Anthropocene.