Great Barrier Reef damage not nearly as great as that casued by natural processes

The Chinese coal carrier Shen Neng 1 gouged a huge scar in the Great Barrier reef:

It could take 20 years or more for the Great Barrier Reef to recover from three kilometres of destruction caused by the grounding of a Chinese coal ship, authorities have revealed.

The Great Barrier Reef Marine Park Authority says the damage to the reef is significant, with large parts of Douglas Shoal "completely flattened" and marine life "pulverised".

The damage is nowhere near as great as that caused by the 100% natural crown of thorns starfish, however:

AIMS [Australian Institute of Marine Science] has implemented the most comprehensive [crown of thorns starfish] monitoring program in the world across the GBR. This long-term program, combined with genetic studies, has shown that COTS outbreaks begin in the north and migrate southward on ocean currents over about a 15 year period. These surveys also show that healthy reefs generally recover between outbreaks, taking 10-20 years to do so.

So human activity (in the form of the Shen Neng 1) has damaged a tiny segment of the reef whereas natural processes destroy huge areas of coral on an ongoing basis. Ain't Mother Nature a bitch.