Thankfully, just around Christmas time the active monsoon trough started and that persisted for just about most of the summer, says Ray Berkelmans from the Australian Institute of Marine Science. So together with high cloud cover and strong winds, that kept us from getting warm conditions for most of the summers.

2009 may have been the second warmest year on record, ending the hottest decade in a century, but that heat didn't translate to ocean temperatures, with a trough delivering last minute respite for much of Australia's oceans.

Those cooler conditions chilled the ocean, protecting much of the Great Barrier Reef. There was some mild bleaching recorded in the southern region but the worst was further north.

On northern Australia, in the Torres Strait region, there was extremely warm weather for a very long period of time; that pushed sea temperatures above the long term summer maximum by several degrees, and of course that's what drove bleaching, says Ove Hoegh-Guldberg from the University of Queensland.

You can never say from one season to the next that the next year is going to be a mass bleaching event, but what we're seeing is that that overall risk is increasing over time as the temperature goes up.

1-2% of reefs are lost each year
A recent study by John Bruno from the University of North Carolina now shows between one and two per cent of the world's tropical corals are being lost each year.

And that translates to a grim outlook for unique places like the Great Barrier Reef, according to Ove Hoegh-Guldberg. You don't have to be a mathematical genius to work out that, you know, 30 to 40 years from now we've lost most of the coral that we have here today, and that's why a lot of us are very concerned.

We don't have a lot of data from the late 60s and the early 70s, but we're quite sure things started really taking off in the early to mid 80s. So our best guess is that we've lost about half of the world's living coral cover over the last three or four decades.