Coral reefs, which sustain roughly a quarter of all marine (0) BIODIVERSITY (DIVERSE), are among the most imperilled ecosystems on the planet. Ocean 1ACID, driven by rising atmospheric carbon dioxide, is steadily weakening the calcium carbonate skeletons on which reef structures depend, while mass 2BLEACH events triggered by marine heatwaves have become alarmingly frequent. Scientists describe the cumulative impact as 3CATASTROPHE, warning that without rapid intervention the damage may become 4REVERSE within a generation. Some species of coral have shown unexpected 5RESILIENT, recovering from bleaching when temperatures subside, yet most 6CONSERVE argue that natural recovery alone cannot keep pace with current losses. Active reef 7RESTORE, including coral gardening and assisted evolution, is gathering momentum, though its proponents readily acknowledge the 8URGE of tackling the underlying climate drivers.