Key Points

• Multiple pieces point to the same finding: reef extent helps determine whether carbon is buried in shallow waters or shifted to the deep ocean.
• The main development is a deep-time reconstruction of carbon-cycle behavior across roughly 250 million years using geological and climate models.
• Reef expansion tends to slow climate recovery after CO2 injections by limiting deep-ocean exchange, while reef collapse tends to speed recovery.
• Modern reef decline from warming and acidification is a recurring concern, but its net effect on future carbon cycling remains uncertain.
• The topic is scientifically coherent and tightly focused, with little evidence of fragmentation beyond differences in phrasing and emphasis.
• This is a structural climate-science theme rather than a short-lived event, because it concerns Earth-system feedbacks operating over geologic time.