THE recent run of destructive bushfires, record monthly maximum temperatures, climate-related protests – plus the controversial approval for a Central Queensland thermal coal mine – have sparked plenty of debates about whether global warming really is an existential threat to the whole country.

While evidence about the consequences of climate change continues to mount, there are still many in the community who remain to be convinced – either that it’s real or whether they, personally, do anything to arrest it.

“Sea surface temperature (SST) has increased significantly across the globe over recent decades. Increases in SST pose a significant threat to the marine environment through biological changes in marine species, including in local abundance, community structure, and enhanced coral-bleaching risk”
Australian Government website Climage Change in Australia

Bureau of Meteorology climate researcher Dr Scott Power said Australia had undoubtedly been experiencing rising temperatures because of the release of greenhouse gases.

Dr Power said the earth’s levels of carbon dioxide, a key greenhouse gas, are now “higher than they have been at for at least 800,000 years”.

CSIRO scientists acknowledge that more than 90 per cent of the energy arising from increased concentrations of greenhouse gas concentrations ends up being absorbed the earth’s oceans.

Warming also causes land ice to melt, further contributing to sea level rise.

In addition, Dr Power said, ocean acidity – as measured by pH levels – had markedly increased, which was likely to cause harm to underwater eco systems as well as beachside environments.

The degradation of the natural environment as well as large variations in weather systems, he said, were likely to ultimately impact not only waterfront residents but also the nation’s tourism economy.

“Unprecedented conditions are difficult to manage,” Dr Power said.

“In some instances, they can push ecosystems and others beyond their ability to cope.”

However, he said, that could be avoided if remedial action is taken.

“What (the Bureau of Meteorology has found) is, by reducing global greenhouse gas emissions, you can reduce the rate of experiencing those unprecedented conditions,” he said, “but it takes about 20 years to kick in.”

That delay was not good news, Dr Power added.

“It doesn’t matter what we do,” he observed. “It’s likely that we’re going to (continue to) experience these unprecedented conditions (more frequent bushfires, droughts, ocean warming and loss of ecosystems).”

“Changes in sea level are caused primarily by changes in ocean density (‘thermal expansion’) and changes in ocean mass due to the exchange of water with the terrestrial environment, including from glaciers and ice sheets.”
Climate Change in Australia

Warming ocean temperatures and an increase in the frequency and intensity of marine heatwaves pose a major threat to the long-term health and resilience of coral reef ecosystems. Globally, large-scale mass coral bleaching events have occurred with increasing frequency and extent since the latter decades of the 20th Century. Bleaching is a stress response of corals, as the water warms the symbiotic relationship between the coral and its zooxanthellae breaks down, turning corals pale. Without these zooxanthellae, most corals struggle to survive, and can ultimately die if the thermal stress is too severe or prolonged. Bleaching on the Great Barrier Reef has occurred in the past, but with increased frequency and extent in recent decades. Widespread bleaching was observed in 1998, driven by higher summer temperatures associated with a strong El Niño combined with long-term warming trends. The last two years (2016 and 2017) have seen mass bleaching over parts of the Reef in consecutive years for the first time, with the northern Great Barrier Reef experiencing bleaching in both summers. In February to May 2016, the bleaching was associated with some of the warmest sea surface temperatures ever recorded, with temperatures well above the long-term monthly averages in February, March and April. As a result, 30 per cent of all coral cover across the entire Great Barrier Reef was lost, and 50 per cent in the northern third was lost between March and November 2016. This was four times greater than previous mass-bleaching events in 2002 and 1998. A second mass bleaching occurred in 2017 linked to another marine heatwave, with temperatures again well above the long-term mean.
Australian Bureau of Meteorology

Australia’s population of 25 million people is largely concentrated along its coastline, so sea level rises are something that already has local and state governments planning for likely adaptations.

Senior CSIRO research scientist Dr Xuebin Zhang said global level sea rises averaged 1.7mm a year over the period from 1900 to 2010, but since 1993, they have averaged 3.2mm a year.

Dr Zhang and his CISRO team use data and projections to visualise what impact persistent sea level rises will have on Australia.

“Since 1993, the global mean sea level rise has increased about 7-8cm. That’s quite large.”

“There’s $200 billion worth of infrastructure that’s is going to be at risk,” Dr Zhang said.

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Worried about where you live in Australia?
Check out the predicted coastal flooding to result from climate change.

Suspect your area is susceptible to storm surge?
Tips from the Bureau of Meteorology

What to know more about climate change in Australia?
Check out this handy government website

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Words: Kahlin van der Borgh
Images: Supplied

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Want to read more?
The original version of this story is one of 30 in a special online Climate Change edition of The Argus that was compiled by Queensland College of Art students from a final-year course called Transmedia Storytelling.