The Great Barrier Reef will be irreversibly damaged by climate change in just 16 years, according to leading reef researcher Ove Hoegh-Guldberg.

The reef has lost about half its coral coverage since the mid-1980s, with increased carbon dioxide concentrations contributing about 10 per cent alongside damage from other sources such as invasive species and farm nutrient run-off, Professor Hoegh-Guldberg, a professor of marine science at the University of Queensland, said.

Environment: Irreversible damage to the Great Barrier Reef can be the result of climate change in just 16 years. Credit:Bloomberg

Climate change, though, is fast taking over as the main threat to the world's reefs as warmer waters increase the frequency of coral bleaching, while acidifying oceans weaken or erode coral structures.

The reef's plight will be a focus of this year's Earth Hour, expected to be observed in 152 nations around the world.