Scientists report that coral reefs have crossed a climate-change threshold, turning into bleached “skeletons,” and warn that further warming will drive widespread extinction.
Critical Points of Climate Change
Scientists have long warned that certain “critical points” in climate change could trigger irreversible damage. A new report concludes that one such point—regarding coral reef bleaching—has already been crossed as global temperatures rise.
Coral Reefs Face Extinction
Coral reefs, built from temperature‑sensitive organisms, cannot escape warming by moving. A 2 °C rise is predicted to endanger most reefs in warm waters, and the latest data suggest the threshold is closer, perhaps already passed, at about 1.2 °C of warming.
Earth has warmed roughly 1.4 °C in under 200 years; continued emissions will almost certainly push temperatures beyond the reef‑critical limit. Within a decade, many reefs will bleach, losing their symbiotic algae and becoming white skeletons, leading to mass local extinctions.
Economic and Ecological Stakes
Reefs support up to a quarter of marine life, including 4,000 fish species, and provide food, jobs, and shoreline protection worth $10 billion annually. Losing them would devastate fisheries, tourism—especially in places like Egypt—and biodiversity.
Potential for Rescue
The report warns that saving segments of reefs requires stopping global warming and, ideally, reversing it to 1.2–1 °C. It also stresses reducing other threats such as ocean acidification, pollution, and overfishing. Some researchers suggest reefs could adapt better than expected, but this depends on halting temperature rise and protecting local sites.
Other Thresholds Loom
The coral loss is just the first of several critical points. Scientists warn that glaciers in the North Pole could melt, Atlantic ocean currents could fail, and Amazon rainforests could die at temperatures as low as 1.5 °C. Each of these events carries catastrophic consequences that scientists urge we prevent.
