The Great Barrier Reef located in Australia is home to over a thousand marine life species, ranging from fish, coral, turtles, sharks and marine mammals. It harbors an immense ecosystem which many species rely on. Scientists have continuously warned of the harmful impact global warming has on the Great Barrier Reef, the world’s largest reef system and the only living organism that can be seen from space. A new study released on Apr. 3 examined the number of adult corals that survived large-scale “bleaching” events in the last two decades, including back to back occurrences in 2016 and 2017, and also the number of new corals created to replenish the reef in 2018. The results found that this “bleaching,” also known as successive ocean heat waves, are compromising the reef’s ability to recover.
According to CNN, the 2,300-kilometer-long (1,500 miles) reef has suffered a major loss in adult corals. This bleaching has caused a “crash in coral replenishment” on the reef as heat stresses brought about by warming ocean temperatures impacted the ability of the coral to heal. “The number of new corals settling on the Great Barrier Reef declined by 89% following the unprecedented loss of adult corals from global warming in 2016 and 2017,” said Hughes, one of the authors of the report. Within the introduction of the report, scientists note that the environmental changes caused by climate change are affecting the capability of the ecosystem to bounce back from damage, escalating the risk of widespread ecological collapse. Major species of coral such as Acropora have shown a 93% decrease in replenishment following the bleaching events in 2016 and 2017.
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Scientists working on this report believe that coral replenishment can occur within the next five to ten years as more corals reach maturity, but only in the absence of another bleaching, which many of them are concerned will not happen with the increasing ocean water temperatures. “Reef resilience is now severely compromised by global warming,” said Baird. With the past sever heat extremes in 2016 and 2017 spreading over nearly 1500 km, the damage affected major sections of the system. Hughes says that “there’s only one way to fix this problem, and that’s to tackle the root cause of global heating by reducing net greenhouse gas emissions to zero as quickly as possible.”
Scientists warn that if this depletion continues, we could be facing an epic “ecological collapse.” According to John Veron, a renowned reef expert widely known as the “Godfather of Coral” stated that “Between a quarter and a third of all marine species across the ocean have some part of their life cycle in coral reefs. So, you take out coral reefs and a third to a quarter of all marine species gets wiped out. Now that is ecological chaos, it is ecological collapse … It’s the beginning of a planetary catastrophe.” Environmentalists and scientists stress the importance of recognizing these massive bleaching events and heat surges as a wake-up call for the world in the battle against climate change. “It’s more than an alarm bell,” said Veron. “It’s an air raid siren.”