February was an unusually hot month in the Great Barrier Reef. The situation caused the most widespread coral bleaching this World Heritage-listed colorful coral network has ever endured. The coming weeks are, therefore, a critical period of heat stress that will dictate how the reef recovers. An Australian Research Council Centre for Excellence in Coral Reef Studies scientist Ove Hoegh-Guldberg, said: “We’re right at the fork in the road.”
A Great Barrier Reef Marine Park Authority chief scientist, David Wachenfeld, said in a weekly update on the reef’s health:
The forecasts … indicate that we can expect ongoing levels of thermal stress for at least the next two weeks and maybe three or four weeks. So, this still is a critical time for the reef and it is the weather conditions over the next two to four weeks that will determine the final outcome.
Across most of the reefs, the ocean temperatures were 0.5 to 1.5C higher than what they usually are in March. Meanwhile, in the southern parts of the marine park close to shore, ocean temperatures were 2 to 3C above average. Those regions had avoided the ravages of the previous bleaching, but this time doesn’t look good.
So far, the Great Barrier Reef Marine Park Authority, the government agency that manages the coral expanse off northeast Australia, has received 250 reports of bleached coral sightings. Last year, the authority downgraded its outlook for the corals’ condition from “poor” to “very poor” because of warming oceans.
Since 1998, the 133,360-square mile natural wonder has been devastated by four coral bleaching events. The summers of 2016 and 2017 saw the deadliest ones. This one now could match those events.
A US National Oceanographic and Atmospheric Administration Coral Reef Watch scientist, William Skirving, said:
At the moment, it’s definitely the most extensive bleaching event we’ve ever had. It’s certainly an end-to-end bleaching event with severe bits at each end and it’s not looking good for the southern end, but it really depends on the weather in the next two weeks.
Mr. Hoegh-Guldberg added:
I’m very worried about the situation given how warm the temperatures are on the Great Barrier Reef and what the projections are. If it cools down a bit, they’ll recover or, if not, we may head off into something not too different from 2016 and 2017.
In the authority’s most recent report, it writes that the greatest threat to the reef is still climate change. Other risks include land-based water runoff, human activity such as illegal fishing, and coastal development. Coral across the planet have shown signs that they are preparing for a mass extinction event, and scientists predict that by 2100 there will no longer be coral reefs on Earth.
