“Water, water everywhere, nor any drop to drink”, wrote Samuel Taylor Coleridge in his poem The Rime of the Ancient Mariner.

Those words succinctly sum up humanity’s difficult relationship with the oceans – our fascination with their barely explored expanse and our fear of the harm they can do us, Mostly our battle with the waves occurs out to sea as we sail across them or dive through them, but there are times when they can intrude upon the dry land where we live.

In many coastal towns and cities around the world, people are fighting a losing war against the sea as it nibbles away at coastlines. On occasion the ocean can spill far into land with storm surges and tidal waves, leaving wreckage in its wake.

So to protect against this, many communities have built high walls and other ugly structures to help defend themselves against the waves.

Yet as we saw in the aftermath of Hurricane Katrina in New Orleans and in countless other smaller storms that lash coastlines around the world, these defences can be easily and catastrophically defeated by the sea.

Emma Johnston, a marine ecologist at the University of New South Wales in Sydney, Australia, believes it may be time to take a different approach.

She told BBC Future’s World-Changing Ideas Summit last month about the promise of ‘blue engineering’ to help us live more harmoniously alongside the sea.

Instead of man-made structures creating “dark zones” beneath the water where algae does not grow and invasive species can take root, she describes in the video above how sea walls can be designed to help marine life flourish instead.

This involves creating structures that mimic those found on natural rocky shores (such as the sandstone of Barangaroo in Sydney, pictured below), providing homes for seaweeds, shellfish and local fish species. Such structures could help to improve our relationship with the sea, Johnston believes, and ultimately make us less fearful of it too.

Source: BBC news webpage