Yes, the reef is being destroyed due to ocean warming and acidification, but this is very much partly the fault of Australia.

They're the #2 coal exporter in the world, about three times as much as the US for example. They consume massive amounts of CO2 per person and have made no efforts to decrease this while the rest of the world has. They burn massive amounts of coal and have no interest in changing this; investment in alternative forms of energy actually went down in recent years. This is despite having tons of space for wind turbines and literally perfect conditions for solar.

Australia also destroys its local environment with overfishing, introducing invasive species, clearing vegetation, and polluting the coasts.

If they want to pretend they're a first world country, they need to act like one.

They’re actually one of the biggest contributors to CO2 emissions. I must confess my country, South Africa is one too.