Climate Change

Coral bleaching occurs as a result of a rise on ocean temperatures. Ocean heatwaves are more common because of global warming and this causes stress for coral. Even a rise of just one degree celsius for only four weeks can trigger bleaching in a coral, and higher temperatures can cook it. If ocean temperatures stay high for eight weeks or longer, the coral cannot recover – and begins to die.

Mining and burning coal and other fossil fuels causes global warming. To stop coral bleaching we must stop the carbon pollution that is heating our planet and cooking our oceans. We must quit dirty coal – and switch to clean renewables now.

Mangroves are critical to marine ecosystems and our climate. They act as crucial nurseries for marine life like fish and turtles, which find shelter and food among the mangrove roots. They also act as critical carbon sinks, absorbing 50 times more carbon than tropical forests by area, according to Professor Norm Duke, a mangrove expert from James Cook University.

Recently around 10,000 hectares of mangrove forests died in the Gulf of Carpentaria, in an area that covered 700km of coastline. The dieback was unprecedented and followed an un-seasonally low Monsoon rainfall, followed by extreme warming with sustained high ocean temperatures.

Kelp forests are the ‘biological engine’ of our Great Southern Reef, which stretches around the southern half of Australia. Great swathes of kelp forests in Australia’s temperate south west have disappeared, and their demise is probably permanent. The Indian Ocean off the mid-Western Australian coast is warming twice as fast as the global average.

The findings come from a 15-year survey of reefs in Western Australia stretching 2000km from Cape Leeuwin in the south to Ningaloo in the north. Over that time nearly 1000 square kilometres of kelp forest have vanished.

With climate change driving warmer waters and more heatwaves, we can expect more of these dramatic changes in the future.