Heavy rainfall, cyclones, droughts and marine heatwaves have damaged 45 per cent of Australia’s fragile coastal marine ecosystems, with some of the damage potentially irreversible, says a new CSIRO study.
More than 8000km of Australia’s coast has been affected by extreme climate events in the last decade.
That’s almost “four times the length of coastline impacted by the Gulf of Mexico oil spill”, said lead author of the study Dr Russ Babcock.
Coastline ecosystems provide habitat and food for thousands of different species of marine life, and contribute to the economies of towns and cities through tourism.
But due to human-induced climate change, extreme events like cyclones, floods, droughts and heatwaves are happening more often, which leaves ecosystems, that often sustain human life, extremely vulnerable.
“Our modelling indicates that the average recovery time for major species groups [from extreme climate events] is around 10 to 15 years. If they happen more often than this, then ecosystems may never fully recover,” said co-author of the study Dr Beth Fulton.
The team who conducted the research studied events like the 2011 Western Australian marine heatwave, the 2016 and 2017 coral bleaching events, and major cyclones.
As an example of how extreme climate events can have roll-on effects even after the event is over, Dr Babcock pointed to Cyclone Yasi in 2011.
“Yasi destroyed swathes of seagrass meadows along the north Queensland coast. When the associated flooding reached the sea the turbid and nutrient-rich waters blocked sunlight, preventing growth of any remaining seagrasses,” he said.
The results of the study paint a worrying picture for the future of Australia’s marine life, as the country sees an increase in the frequency and intensity of extreme climate events.
Outside of the study, Dr Babcock has been investigating short-term strategies that could help marine ecosystems adapt quickly to the effects of climate change.
“We have developed industrial-scale methods to harvest coral spawn, grow it out in at-sea aquaculture systems and redistribute across damaged reefs,” he said.
But to prevent long-term damage these strategies have to be coupled with “efforts to reduce atmospheric greenhouse gases that drive climate change,” said Dr Babcock.