AN Irish scientist who is the world’s leading authority on coral reefs has warned that the chances of the natural wonders surviving in a changing climate are diminishing.

Professor Terry Hughes, marine biologist at James Cook University in Queensland, Australia, told an online seminar hosted in Dublin of his despair at witnessing the loss of half the Great Barrier Reef in five years.

He said it would not be possible to reconstruct lost reef and the only hope was that global greenhouse gas emissions dropped and temperature stabilised.

“I am the scientist at the start the disaster movie,” he told the Dublin Institute of Advanced Studies event, referring to the trope whereby almost every plot begins with an expert being ignored.

Professor Hughes is interviewed in David Attenborough’s new Netflix documentary ‘Breaking Boundaries’, in which he fights tears describing the impact of climate change on the natural world.

He told Friday’s webinar that scientists were hugely frustrated by the lack of global action on the climate crisis.

Over-fishing and pollution also damaged coral reefs but temperature rise was having the most dramatic effect.

The Inchicore native said when he was a student at Trinty College, he had never heard of coral bleaching outside of laboratory experiments.

“You knew that if you took coral into a lab and tortured it – made it too hot, too cold, exposed it to pollutants - it would get stressed and bleached,” he said.

He had since witnessed the five major bleaching events suffered by the Great Barrier Reef, the largest living organism on Earth.

“The first was in 1998 which was the hottest year on record. The next was in 2002 which was hotter. Then another in 2016 which was hotter again and that was repeated in 2017.

“The most recent was in 2020. February that year we had the hottest sea temperatures on record.

“Temperatures are getting hotter, the bleaching is escalating and the gap between one event and the next is shrinking. That’s very concerning,” he said.

Coral get their colours from microscopic algae that live within them and on which they depend for vital functions.

When stressed, they expel the algae and turn white. If they are not recolonised by algae, they die.

Fish disappear and coastal communities, particularly in developing countries, who rely on the reefs for fishing and tourism are devastated.

Professor Hughes said coral could be supported to regrow but at a prohibitive cost of several million dollars per hectare.

“The challenge is not to grow new reef artificially but to look after the survivors,” he said. “You have to deal with the root causes of the decline.”

He said he could only give “a cautious yes” when if asked if there would be any coral reefs in 100 years’ time.

“What we need is for global emissions to drop to zero and temperatures to stabilise, and there is no time to lose to achieve that.”