"Our reefs could look like this in specific areas that are hit by massive typhoon" would have been more accurate. Ships/dredging would have a totally different damage profile.
Actually, the statement is fairly accurate. Imagine this scenario: the effects of dredging (resuspension of sediments) results in reduced settlement rates of branching Acropora, but sub-lethal levels of stress mean that the adult populations survive. A category 2-3 cyclone come by and flattens the branching Acropora leaving a scenario that looks much like that photograph - except at Apo Island, there are no chronic stressors and larval recruitment ends up in rapid recovery 5-10 years after the cyclone. With impaired rates of larval recruitment, the section of reef impacted by dredging won't show signs of recruitment. Coral reefs recover fairly well after acute disturbance (e.g. cyclones), but reefs that are impacted by chronic disturbance often fail to recover from acute disturbances. Considering that branching Acropora (much like in that photograph) on the inshore reefs showed signs of reduced recruitment rates back in the early 80's, any additional chronic stress is likely to further impact on the inshore GBR. Granted, photos of inshore reefs wouldn't look anywhere near as blue or clear as that photograph, which is probably why they used the Apo example.
Because they don't have actual photos of a reef damaged by shipping and dredging... care to guess why? Because Shipping damage to reef in Australia is so fucking insignificant that it's actually hard to find anywhere that has actually been significantly damaged by shipping.
Actually, just typing "shenzen great barrier reef" into google images gets a few good photos of the impacts of shipping damage on the Great Barrier Reef, like this, this. I actually don't disagree with you that the risk of ship grounding is very minor (and the impacts highly localised), but there are images out there. The reason they don't have photos of the reef damaged by dredging is probably look more like this.
The area's that have suffered this kind of damage would pale in comparison to the damage in the misleading photo, which is exactly why they consciously chose to use it.
To be honest, they look pretty similar.
As for Dredging, that's definitely a serious concern. Far far behind fertiliser run off, but still a concern. Again, though, totally different damage profile and nothing to do with what was pictured.
Actually, I entirely agree with you with the relative importance of the impacts, and I also agree with you that Greenpeace probably should have done their homework and not left themselves open to such criticism, but I do disagree with your statements on the "damage profile".
