Budget Indian Travelers The Great Barrier Reef is one of the planet’s most extraordinary natural wonders, its largest coral reef system and the only living organism that can be spotted from space.Half of the Great Barrier Reef has been bleached to death since 2016. Mass coral bleaching, a global problem triggered by climate change, occurs when unnaturally hot ocean water destroys a reef’s colorful algae, leaving the coral to starve. The Great Barrier Reef illustrates how extensive the damage can be: Thirty percent of the coral perished in 2016, another 20 percent in 2017. The effect is akin to a forest after a devastating fire. Much of the marine ecosystem along the reef’s north coast has become barren and skeletal with little hope of recovery.

Global Warming has caused such extensive damage to the Great Barrier Reef that scientists say its coral may never recover. According to a study published Wednesday in the journal Nature, baby coral in Australia’s Great Barrier Reef have declined by 89% due to mass bleaching in 2016 and 2017.

The study measured the number of surviving adult corals in the Great Barrier Reef — the world’s largest reef system — following extreme heat stress, as well as how many new corals it was able to replenish in 2018. Deadly back-to-back bleaching events devastated the reef, and now its ecosystem is struggling to recover. Not only have ocean heat waves led to a dramatic decrease in new coral, but also a change in the types of coral species being produced.

Researchers studied adult and baby coral from 47 locations in various years from 1996 to 2016, then returned to the reef in 2018 to collect the same data. They found that a majority of the northern region’s coral has not been able to recover following mass bleaching events, leading to a decline in new coral as well.

According to the study, the biggest decline in replenishment came from the reef’s dominant species of adult coral, called Acropora, which supports thousands of other species. It experienced a 93% drop compared to previous years. The change is likely to reduce the reef’s overall diversity, which will make it even less resilient to future bleaching events. “Our study shows that reef resilience is now severely compromised by global warming,” said co-author Professor Andrew Baird.

Scientists expect the coral may recover over the next five to ten years — but only if another mass bleaching event doesn’t occur during that time. That’s unlikely given the current trajectory of climate change. The researchers said southern reefs that did not suffer bleaching are still in good condition, they are not close enough to replenish the damaged reefs that are further north.

Bleaching occurs when corals are stressed by unusual environmental changes, such as increased sea temperature. They respond by expelling the symbiotic algae living in their tissues, causing the coral to turn white. Without the algae, the coral loses its major source of food and often can’t survive. Widespread coral bleaching during back-to-back summers was particularly toxic, as it did not leave enough time for the corals to fully recover.

The Great Barrier Reef — which stretches for more than 1,400 miles off the coast of Australia — has gone through four mass bleaching events due to above-average sea temperatures in 1998, 2002, 2016 and 2017. Time periods between future bleaching events are expected to continue to shrink as global warming intensifies. To tackle the root cause of global heating by reducing net greenhouse gas emissions to zero as quickly as possible.