The only way to save the Great Barrier Reef is to reverse climate change, according to a recent study published in Nature. This might seem like the obvious answer, as the warming oceans cause the corals to bleach, but it is an important fact to settle. Now the question remains: Is there time to save it?

It was previously suggested that while climate change did pose a major threat to the reef, this could be mitigated by cleaning up the water and preventing overfishing. The theory was that pollution and fishing stressed the coral to such a degree that when the waters start to warm, it's much more likely the reef will die when a bleaching event occurs. It seems, however, that this idea has finally been put to rest.

By studying the three major bleaching events that have occurred on the Great Barrier Reef over the last 20 years, the researchers found that both the temperature of the sea surface and the duration at which it stayed above average were the primary agents driving the bleaching and, in some cases, eventual death of the coral.

This raises significant questions about how the reef is now managed. Australia has spent a lot of time and money on improving the health of the reef by, for example, preventing agricultural runoff from the coast into the shallow seas off Queensland, as well as protecting large parts of it from fishing. As a result, it is considered one of the best managed reefs in the world. But this may all mean nothing if, as this latest study suggests, the real threat is actually coming from man-made climate change.

^{During last year's bleaching event, most of the southern reef, seen here, managed to escape damage. Tane Sinclair-Taylor}

During the 2016 bleaching event, for example, the corals in the northernmost part of the reef were the hardest hit. To many, this was a serious worry considering that these parts are the least accessible and so least visited, making them some of the most pristine areas along the entire reef. But it is precisely because they are so far north that they were so badly affected. This is because the waters there are on average warmer and so any rise in sea surface temperature impacts them far worse than those further south. It now looks likely, however, that even the southern reef will get hit, as the reef is on the brink of an unprecedented second bleaching in two years.  

Yet it is not only the coral and all the thousands of species that will suffer. The Great Barrier Reef is thought to support about 70,000 jobs and bring in an astonishing $7 billion of tourist revenue. If the reefs die, many will suffer.

Unfortunately, the Australian government isn’t exactly known for its strident stance against climate change. Despite the fact that the reef sits off the coast of Queensland, the state has recently approved the establishment of Australia’s largest coal mine, and with most of the fossil fuel being shipped to China, the expansion of a coal port will be built near the reef itself.

The point of the study is that the reef can be saved. If greenhouse gas emissions are dramatically slashed and renewables embraced, global temperatures can be slowed and, in time, stabilized. This would prevent the oceans from warming too much, and hopefully the corals could then have time to adapt. However, it requires the political will to do so. 

^{The Abbot Point port is being expanded so that more coal can be shipped through the reef. Greenpeace/Tom Jefferson}