Skip to main content
News_

Shore break

22 September 2015
Coastal erosion of Australia's beaches could be worse than previously predicted.

The projected upsurge of El Niño and La Niña events will lead to extreme flooding and erosion in populated regions across the Pacific including Australia, according to a new study.

Increased El Niño and La Niña events are likely to cause more erosion in the southern corners at beaches like Narrabeen.

The impact of these storms is not presently included in most studies on future coastal vulnerability, which look primarily at sea level rise. New research data, from 48 beaches across three continents and five countries bordering the Pacific Ocean, suggest the predicted increase will exacerbate coastal erosion irrespective of sea level rise affecting the region.

Researchers from 13 different institutions, including the University of Sydney, analysed coastal data from across the Pacific Ocean basin from 1979 to 2012. The scientists sought to determine if patterns in coastal change could be connected to major climate cycles. Data came from beaches in the mainland United States and Canada, Japan, Australia, New Zealand and Hawaii.

The research was published in Nature Geoscience today.

Although previous studies have analyzed coastal impacts at local and regional levels, this is the first to pull together data from across the Pacific to determine basin-wide patterns. The research group determined all Pacific Ocean regions investigated were affected during either an El Niño or La Niña year. When the west coast of the U.S. mainland and Canada, Hawaii, and northern Japan felt the coastal impacts of El Niño, characterized by bigger waves, different wave direction, higher water levels and/or erosion, the opposite region in the Southern Hemisphere of New Zealand and Australia experienced “suppression,” such as smaller waves and less erosion. The pattern then generally flips: during La Niña, the Southern Hemisphere experienced more severe conditions.

Co-author Professor Andrew Short from the School of Geosciences says forecast increases in the strength of El Niño and La Niña weather events driven by global climate change means coastal erosion on many Australian beaches could be worse than currently predicted based on sea level rise alone.

“During enhanced La Niñas we can expect more tropical cyclones and east coast lows off the coast, leading to damaging cyclones and storm surges along the Queensland coast and severe beach erosion along the New South Wales coast. The more benign El Niños will bring fewer cyclones and long periods of lower southerly waves. These will rotate the beaches to the north, building out the northern ends, while severely eroding the southern corners of the beaches, where most development usually occurs. These impacts will take place irrespective of the amount of sea level rise.

“This study significantly advances the scientific knowledge of the impacts of El Niño and La Niña,” said Patrick Barnard, USGS coastal geologist and the lead author of the study. “Understanding the effects of severe storms fuelled by El Niño or La Niña helps coastal managers prepare communities for the expected erosion and flooding associated with this climate cycle.”

We can expect more tropical cyclones and more East Coast lows off the coast.
Professor Andrew Short, School of Geosciences

The study also investigated the coastal response of other climate cycles, such as the Southern Annular Mode, which has impacts at the same time in both hemispheres of the Pacific. The data revealed that when the Southern Annular Mode trended towards Antarctica, culminating in more powerful storms in the Southern Ocean, wave energy and coastal erosion in New Zealand and Australia increased, as did the wave energy along the west coast of North America. Other modes of climate variability, such as the Pacific North American pattern, which relates to atmospheric circulation in the North Pacific, are linked to coastal impacts that are more tightly restricted to the northern hemisphere.

Linking coastal erosion to natural climate patterns, such as El Niño/Southern Oscillation and the Southern Annular Mode, can be challenging.

“Shoreline behavior can be controlled by so many different factors, both locally and regionally, that it’s been difficult to isolate the signal until now. However, utilizing the many years of data we were able pull together in this study enabled us to definitively identify how the major climate drivers affect coastal hazards across the Pacific,” said Patrick Barnard. “This will greatly enhance our ability to predict the broader impacts of climate change at the coast.”

“Coastlines of the Pacific are particularly dynamic as they are exposed to storm waves generated often thousands of miles away. This research is of particular importance as it can help Pacific coastal communities prepare for the effects of changing storm regimes driven by climate oscillations like El Niño and La Niña. To help us complete the puzzle, for the next step we would like to look at regions of the Pacific like South America and the Pacific Islands where very limited shoreline data currently exists,” said Mitchell Harley of UNSW Australia, and a coauthor of the paper.

“It's not just El Niño we should be concerned about," said Ian Walker, professor of Geography at the University of Victoria and coauthor of the study. “Our research shows that severe coastal erosion and flooding can occur along the British Columbia coast during both El Niño and La Niña storm seasons unlike further south in California. We need to prepare not only for this winter, but also what could follow when La Niña comes.”

The published paper, “Coastal vulnerability across the Pacific dominated by El Niño/Southern Oscillation” is available online

Jocelyn Prasad

Media and Public Relations Advisor
Phone
  • + 61 434 605018
Mobile
Email
Address
  • Level 2 Services Building G12

Related articles

17 June 2016

Satellite testing launches

Three small Australian cube-sized satellites will be launched from the International Space Station to research new regions that could impact technology used on Earth, with the University of Sydney leading development of one of the CubeSats, undergoing testing in Canberra this week. 

23 June 2016

New insights into the causes of sudden cardiac death in the young revealed

Sudden cardiac death claims the lives of 2-3 young Australians every week. 

23 June 2016

Researchers help Qantas fly cleaner and cheaper

Unveiled this week, the new flight planning system is the result of a world-first, four-year project conducted at the University’s Australian Centre for Field Robotics (ACFR). The team comprising four aeronautical research fellows, 3 PhD candidates and 10 software engineers worked on designing new system models.

21 June 2016

University welcomes new Sydney School of Entrepreneurship

The University of Sydney has welcomed the NSW Government's $25 million pledge to create the Sydney School of Entrepreneurship as a new collaborative venture in the higher education sector. 

15 June 2016

Robotics for farms of the future

With Australia’s farming future looking increasingly reliant on automated technologies, such as low-cost robotics, the industry’s vision should include more support for agri-technology start-ups, retraining growers and agronomists for a digital age, and introducing rural kids to hands-on robotics.   

02 June 2016

Why $1 a litre milk won’t take Australia from the mining to the dining boom

Despite demand from overseas markets such as China, Australia’s milk wars illustrate the difficulty of taking a low-cost commodity approach to competition. Farmers need to embrace digital disruption, promoting our renowned clean, green produce by using tools that are increasingly available to detail the journey from behind the farm gate to the consumer.

16 June 2016

MadMaker tours rural NSW

MadMaker is the brainchild of electrical and information technologies engineer Dr Abelardo Pardo, a specialist in technology-based learning. It was designed to inspire students who may not have previously considered a future career in engineering, technology or science-related fields.

13 December 2016

Confidence boost linked to weight loss in smartphone trial

Confidence is key when motivating young people to change their diet and exercise habits, new research from the University of Sydney shows.

13 December 2016

New diamond harder than ring bling

An international team has created a harder-than-diamond Lonsdaleite diamond – usually found at the site of meteoric impacts. Unlike cubic diamonds, the hexagonal creation is more likely to be used in manufacturing.

13 December 2016

Sydney alum off to Stanford as Monash scholar

University of Sydney alumnus Dr Martin Seneviratne has been named the 2017 Roden Cutler NSW John Monash Scholar. The award will see Dr Seneviratne head to Stanford University to continue his ground-breaking work into clinical informatics.