Climate change to put dunes on the move

June 20, 2014
Climate change to put dunes on the move
Dunes on SA’s West Coast. Credit: AD Short.

(Phys.org) —The instability of coastal sand dunes – already an issue for Adelaide's suburban beaches – is likely to worsen as sea levels rise with global warming, according to Flinders University Professor Patrick Hesp.

And deprived by human activity of the space to retreat from higher sea levels, Professor Hesp says urban seaside may eventually be lost to erosion.

Professor Hesp, Strategic Professor of Coastal Studies in the School of the Environment at Flinders, said that globally sea levels are currently increasing by 3.2 millimetres each year.

"While this may not seem much, projections for the year 2100 show an increase at a lowest estimate of 20 to 30 centimetres, ranging up to 190 centimetres for the highest estimates," he said.

Professor Hesp said that the fore dune – the first dune at the back of the beach – has the capacity to move upwards and backwards with rise, if it has the space.

"The central problem is that the Adelaide coast no longer has that space, because we've built right up to the beach," Professor Hesp said.

"The dunes will be looking to translate landwards, but if you have a seawall at the back of the beach, they have nowhere to go and will erode."

Professor Hesp said some Sydney councils are attempting to forestall the problem by buying up seafront properties to convert them into coastal reserves.

South Australia's coastal dune systems are among the most extensive in the world, Professor Hesp said.

In unpopulated areas, most dunes will gradually move backwards as the sea level rises, mimicking the action of the dunes ahead of the historic following the last Ice Age which brought the shoreline up from 130 metres below its current level.

But a crisis for beaches in coastal towns could come quite quickly, Professor Hesp said.

He said that if rising sea levels are accompanied by the blend of hotter, drier and windier conditions that are predicted as part of climate change, vegetation that helps to stabilise dunes will potentially die off or the vegetation cover will be reduced.

"Sea level rise will destabilise the dunes on the front, which will probably create greater activity, but if, on top of that, there is a few per cent change in rainfall, wind or evapo-transpiration, those things will all lead to greater dune instability."

Because of the number of variables, it is very difficult to predict the degree of severity or the speed of climate change-related effects.

"But we are likely to see more active dune fields than we did, and potentially the breakdown of some currently stabilised dune fields," he said.

Explore further: Scientist finds alternate explanation for dune formation on Titan

Related Stories

Image: Great Sandy Desert, Australia

April 9, 2013

(Phys.org) —In northwest Australia, the Great Sandy Desert holds great geological interest as a zone of active sand dune movement. While a variety of dune forms appear across the region, this astronaut photograph features ...

Researchers bulldoze desert to learn how sand dunes form

January 13, 2014

(Phys.org) —A team made up of members from research facilities in France and China has found that theoretical models built to describe sand dune formation align very closely with how they actually form in nature. In their ...

Image: Martian sand dunes in spring

March 7, 2014

(Phys.org) —Mars' northern-most sand dunes are beginning to emerge from their winter cover of seasonal carbon dioxide (dry) ice. Dark, bare south-facing slopes are soaking up the warmth of the sun.

Recommended for you

Study calculates the speed of ice formation

August 3, 2015

Researchers at Princeton University have for the first time directly calculated the rate at which water crystallizes into ice in a realistic computer model of water molecules. The simulations, which were carried out on supercomputers, ...

'Snowball earth' might be slushy

August 3, 2015

Imagine a world without liquid water—just solid ice in all directions. It would certainly not be a place that most life forms would like to live.

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

TegiriNenashi
3 / 5 (2) Jun 20, 2014
Couple alternative headings:
"Dunes habitat threatened by climate change"
"Dunes climate refuges demand global dismantling of sea walls"
collette_johanssen
not rated yet Jun 21, 2014
Climate change may harm you and your family.. You should have to be very careful, because weather are very unpredictable..First thing in the morning you wake up with the sunny weather, and then later in the afternoon or evening?? it could rain or snow..So, you should be ready at all times and Subscribe to Safekidzone, to have you and your family's Panic Button.. In time's of Emergency Situation? You could easily connect or escalate to the 911..Regarding this article check out this link: http://safekidzon...91a0b72c

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.