16 March 2009

Stifling heat, heavy rainfall causing significant flooding, and destructive winds from cyclone Hamish, have all compounded to have a hard hitting impact on the Great Barrier Reef.

Great Barrier Reef Marine Park Authority (GBRMPA) Chairman, Dr Russell Reichelt, said a summer of extreme weather brought a triple whammy of pressures to the Great Barrier Reef.

“Sea temperatures across most of the Reef rose a massive 2-3 degrees above average in December which meant this summer was shaping up to be one of the worst years on record for coral bleaching due to the extreme heat.

“Above average sea temperatures are very stressful to corals and prolonged heat causes bleaching and ultimately coral death, so we were very concerned about the outlook for the Reef.

“In January, we got a reprieve from the risk of heat induced bleaching as wind and cloud cover from the monsoon cooled temperatures. But this was a mixed blessing for the Reef because storms in January and February caused record levels of rain and extreme flooding.

“This was a one in a hundred year flood event, where, in a rare consequence, we are seeing plumes covering very large areas of the Marine Park.

“Flood plumes are also extremely stressful to corals and we’ve had reports of severe bleaching and coral death on reefs between Cairns and the Whitsundays.

“To make matters worse, destructive wind gusts from Severe Tropical Cyclone Hamish affected more than 50 per cent of coral reefs in the Marine Park.  

“Although we have yet to survey the effected areas, we expect the storm may have caused severe reef and island damage.

All of these things individually cause stress to the Reef but Dr Reichelt said it was their combined impact that was most worrying.

“Historically the Reef has been resilient to events like this, but it is rare; possibly unprecedented; to have three such events in such a short period of time.

“It’s been a summer of hard knocks for the Reef and given the slow recovery of corals, we are likely to see the impacts of this summer for years to come.

“In fact, some reefs were still recovering from damage caused by the 1998 and 2002 mass bleaching events and other localised disturbances like cyclone Larry and a series of flood plumes over the past decade.

“Because it can take reefs up to 20 years to fully recover, these recent events are a real set back for reef recovery in some areas.”

The GBRMPA is working with the Australian Institute of Marine Science and the Environmental Protection Agency to assess the damage at inshore and mid-shelf reefs between Townsville and Lizard Island.

Dr Ian Poiner, CEO of the Australian Institute of Marine Science, said that extreme weather was likely to become commonplace.

“We’ve been tracking the health of the Reef over decades and we have seen an overall decline in coral growth on the Reef.

“Decreased growth and increased disturbance are a worrying combination.”

Of all developed countries, Australia is likely to be most impacted by climate change and the Reef is already seeing signs of the changes to come.

Dr Reichelt said it was important to buy time for the Reef from the worst effects of climate change and extreme weather by bolstering its overall health.

“While the Great Barrier Reef is recognised internationally as being the healthiest and best managed reef system in the world, we can’t afford to be complacent.

“There is much work still to be done and with extreme weather events becoming more frequent, now more than ever we need to remain vigilant.”

Dr Reichelt said that keeping the Reef as healthy as possible required a two pronged approach, mitigating the impacts of climate change and working to improving its resilience.

While the Reef has experienced setbacks this summer, it is still faring better than most of the world’s reefs and remains a fantastic destination for tourists.

For more information on reef-friendly practices visit www.gbrmpa.gov.au