Coastal infrastructure in urgent need of rethink: Aussie scientists

Source: Xinhua| 2019-09-05 11:40:07|Editor: Yamei
Video PlayerClose

SYDNEY, Sept. 5 (Xinhua) -- Australian researchers have called for an urgent rethink of coastal infrastructure, issuing a world-first global framework to guide policy makers in designing resilient coastal ecosystems.

The report released on Thursday by the University of New South Wales (UNSW) suggests that to cope with climate change, policy makers and scientists take a much more active role in shaping natural coastal environments beyond purely defensive or damage-mitigating measures.

One of the suggested methods, they refer to as "ocean gardening" represents a far more hands on approach than has ever been seen as necessary.

"Coastal defences are now being designed to mitigate climate threats to infrastructure, but they may be causing more damage than good," lead author Mariana Mayer Pinto said.

"Furthermore, 'holding back the sea' using built infrastructure isn't necessarily cost-effective; approaches focusing on the conservation or restoration of natural ecosystems that buffer the impact of storms, such as coral reefs, oyster reefs, and salt marshes have, in many instances, proven cheaper and more effective than artificial defence structures," Pinto said.

Where building physical infrastructure is unavoidable the researchers modify their advice depending on latitudinal location.

At lower, more tropical latitudes, organisms are more likely to be affected by thermal stresses such as warmer waters - therefore their advice is to create environments which are more accommodating and provide places to shelter from the heat.

"For example, standard seawalls are quite flat - so if you retrofit them by adding shaded and well-flushed rock pools, you get water-retaining features that may serve as climate refuge for intertidal organisms, and you can create crevices and ledges that also provide shade," Pinto said.

In more temperate, higher latitude areas, the researchers said that a significant environmental pressure is the global redistribution of organisms, whereby as a result of climate change, tropical species are invading temperate zones and temperate species are moving further towards polar waters.

In this case, they recommend undertaking a more radical approach of biological intervention - or what they refer to as "ocean gardening."

"For example, if there's an invasive species we don't want in an environment, we try to 'harvest' or remove it, and if it's a species we'd like to see more of because it plays an important ecological role in the ecosystem, we seed or transplant it," Pinto said.

While this approach is extreme, and my result in unforeseen consequences such as the introduction of invasive species, according to the researchers, more passive conservation strategies are now insufficient to tackle the challenges.

"We're now at a point in global climate change where taking no action is potentially more harmful to coastal ecosystems than intervening based on the best available evidence," senior author, Professor Emma Johnston said.

"Unfortunately, we don't have time to research all the possible outcomes, as environments are changing at very high speed, but we can start with small-scale trials, and then use expert evidence and a risk-based approach to re-designing our coastal management and coastal construction," Johnston said.