Last updated September 30, 2019 at 10:49 am
Sea levels are continuing to rise with some of the impacts coming hard and fast, and our coastal communities are on the front line.
Sunset at Surfers Paradise, with tall buildings in the background, Gold Coast, Queensland, Australia
Why This Matters: Without further action, our coastal communities are at risk.
Sea levels could rise by as much as one metre by the end of the century if we do nothing to combat climate change, according to the lastest IPCC Special Report on the Ocean and Cryosphere in a Changing Climate.
IPCC report author Nerilie Abram from the Australian National University says the report shows “the ocean is suffering from the effects of climate change that are playing out here and in the farthest reaches of our planet”.
Sea level rise is getting faster, and according to the report, the acceleration is largely driven by increasing rates of ice loss from the Greenland and Antarctic ice sheets.
It is a finding John Church from the University of New South Wales agreed with, adding that “the dominant cause of sea level rise since 1970 is our release of greenhouse gases”.
Deeper: Sea level rise is accelerating
On top of rising sea levels, the report says that predicted increases in extreme waves, tropical cyclones and rainfall could combine to create a recipe for far more extreme sea level events and coastal hazards.
Coastal communities will experience once-in-a-century extreme flooding
According to Abram, if we do not act to limit further climate change, Australia’s coastal cities and communities can expect to experience what was previously a once-in-a-century extreme coastal flooding event at least once every year by the middle of this century – in many cases much more frequently.
“In Australia, adapting coastal communities to unavoidable sea level rise is likely a priority,” she says.
“There are a range of possible options, from building barriers to planned relocation, to protecting the coral reefs and mangroves that provide natural coastal defenses.”
Something else that is particularly relevant to Australia is the note in this report that the Southern Ocean is sucking up heat. Since the 1970s it has stored 35-43 per cent of the total heat in the upper ocean, and that share is increasing.
Deeper: Things are heating up in the oceans
Overall, the report says the rate of ocean warming has doubled since 1993 and global oceans take up more than 90 per cent of the excess heat in the climate system.
It is also now very likely that between 84 and 90 per cent of marine heatwaves that occurred between 2006 and 2015 are attributable to man-made global warming.
Climate change impacts are coming faster than we thought
Chapter author Nathan Bindoff from the University of Tasmania says that marine heatwaves have doubled since 1982 and “amazingly the intensity of those heatwaves and the duration of those heatwaves is tending to increase as well”.
But he warned it is not just the physical ocean properties that are changing rapidly. The report also covers the impacts on ecosystems and impacts on the services that the environment provides for humans.
“These things, when you line them up and connect them up there’s a lot of evidence already that the climate system has impacted on those services,” says Bindoff.
His co-author, Jess Melbourne-Thomas from CSIRO, says these services ranged from food supply and cultural values, through to tourism and coastal carbon sequestration.
But as report after report is published by the IPCC showing a consistent picture of climate change, the clear message, according to Pep Canadell from CSIRO, is that above all, greenhouse gas emissions need to peak immediately and come down at a rapid pace if we are to avoid the worse impacts of climate change.
“Some of the impacts are as expected and previously projected. For others, they are coming faster and punching harder than we had anticipated,” he says.
You can read the full expert reaction here.
