More than 12,000 kilometres of Australia's sandy beaches are threatened by coastal erosion by the end of the century, with greater losses predicted if greenhouse gas emissions remain high.
The projections, made by European researchers and published in Nature Climate Change on Tuesday, used satellite data that tracked shoreline change from 1984 to 2015. They found a "substantial proportion" of the world's sandy coastline is already eroded, a trend that could worsen as climate change pushes up sea levels.
 |
| Australia's coastline has already seen significant areas of retreat in recent years, such as at Inverloch, in Victoria. Credit: Google News Lab |
Should greenhouse gas emissions continue to rise through the century - the so-called 8.5 Representative Concentration Pathway - Australia's sandy coastline at risk increases to 15,439 kilometres, the paper said.
"You have a long coastline and part of the coast is very mildly sloping" and is therefore susceptible to erosion, said Michalis Vousdoukas, a coastal oceanographer at the European Commission and the paper's lead author.
"Melbourne is worse than Sydney," Dr Vousdoukas told the Herald and The Age, adding Brisbane and Adelaide's beaches fell between the two in terms of vulnerability to erosion.
The researchers said global sea levels had been increasing "at an accelerated rate during the past 25 years and will continue to do so with climate change".
So far, most of the increase had come from the thermal expansion of warmer water but, by mid-century or so, the increase in sea levels would likely come more from melting ice sheets, Dr Vousdoukas said.
Following the lower emissions pathway would prevent about 22 per cent of the projected coastal retreat by 2050 and 40 per cent of it by 2100. "This corresponds to a global average of around 42 metres of preserved sandy beach width by the end of the century," the paper said.
After the Sydney area experienced its wettest weekend in more than 20 years, beach erosion and massive amounts of sea foam can be seen at Collaroy on the Northern Beaches.
Some nations would be harder hit on a relative basis than Australia, with Suriname, Pakistan, El Salvador and Guinea-Bissau among those countries facing the loss of more than 80 per cent of their sandy coasts.
 |
| Stockton, near Newcastle on the NSW coast, is another area where the beach is in retreat. Credit: Google News Lab |
Carribean states, for instance, could see beach retreats of more than 300 metres, with "substantial implications" for economies dependent on tourism, the paper found.
Kathleen McInnes, head of CSIRO's coastal extremes group, said the paper was "useful at a macro level", and noted its own limitations such as an exclusion of "backshore" infrastructure such as sea walls that would limit beach retreat in built-up areas.
The paper's assessment, though, that the impacts of big storms would tend to be a "second-order effect" compared with the background effect of remorselessly rising sea levels "was a very plausible finding" and in line with CSIRO's own research, Dr McInnes said.
Still, major storms - which climate scientists predict will become more intense as the atmosphere warms - can be important.
 |
Narrabeen on Sydney's northern beaches is among the most vulnerable near the Harbour City.
LEFT September 2003 RIGHT April 2019
Credit: Google News Lab
|
Links
- The new dread of Australia's once-loved long, hot summer
- Summers are starting earlier, finishing later and winter is in retreat
- The early warning system being developed to shore up Australia's beache
- Sandy coastlines under threat of erosion
- Sea level rise will see 40pc of Australia's beaches lost, predicts new study
- Half of world’s sandy beaches could disappear due to sea level rise by 2100
- Rising Sea Levels, Coastal Erosion: New Report Says Half the World's Sandy Beaches at Risk From Climate Change By 2100
No comments :
Post a Comment