“The Last Wild Places”: the show in Venice about the Earth’s escalating salt marsh crisis | Installation

En old novels, salt marshes are still seen as barren, desolate desert landscapes, but today they are still seen as flat, grey and inhospitable landscapes. Rainforests, grasslands, seas and even peat bogs have their prominent champions. But now there is someone championing the magnificence of tidal meadows: Sophie Hunter, theatre maker and opera director, hopes her new performance installation will make us care more about these important, carbon-sequestering coastguards.

A salt marsh doesn't stand out, perhaps because not much seems to happen in these expanses of grass and stream. “And then it disappears twice a day, which is extraordinary,” says Hunter, sitting miles from any marsh in a north London pub, visibly refreshed after returning from her traditional family holiday of swimming, sailing and enjoying the salt marshes of a place she asks me not to reveal with her husband Benedict Cumberbatch and their three sons. “Salt marshes are the last wild places in Britain. These liminal tidal spaces are often associated with outcasts, people living on the fringes of society. How can we change our perceptions and realise how valuable they are on so many levels?”

Hunter's interpretation of the story of an outcast – the biblical figure of Lot's wife, who was turned into a pillar of salt for daring to look back at the homeland she had been forced to flee – in a new performance installation, Salt of the Earth, is an urgent plea to save the salt marshes. Each square kilometre of them sequesters and stores far more carbon than the same area of ​​forest, in addition to providing natural flood protection and sanctuaries for threatened species. Yet more than half of the planet's salt marshes have already been degraded or destroyed. And every year more are lost to development, rising sea levels and, ironically, man-made flood defences.

The ingredients of Salt of the Earth, which premieres in a former salt warehouse in Venice to coincide with the 81st Venice International Film Festival, are undeniably fascinating. Audiences enter a landscape of salt – tons of it. Here, a monologue is delivered by Lot's wife (played by Olwen Fouéré), giving Hunter a name, Erith, and a new agency. Determined to bear witness to the marshes she loves, Hunter says, “she chooses to look, to stay, to pay attention, rather than to leave, to forget and to move on. That is the heart of the play – the potential sacrifice inherent in this act.”

The monologue was written by novelist Megan Hunter (Sophie's sister-in-law) and followed by an installation film and a choral climax composed by Isobel Waller-Bridge. The 45-minute installation asks: “What does it mean to bear witness? To pay attention?” says Hunter. “This is absolutely critical to saving the environment. As the poet Mary Oliver said, 'Attention is the beginning of devotion.' Pay attention, connect, and then there's something you want to fight for.”

Hunter's interest in salt marshes is rooted in childhood holidays on the estuaries of the Isle of Wight, where six generations of her mother's family grew up. When she visited Venice to explore the possibility of creating an environmental work, she was drawn to the part that most tourists overlook: the vast lagoon that surrounds the ancient city. The lagoon is the largest wetland in the Mediterranean, but more than three-quarters of the salt marshes have been destroyed in the last century, mainly due to development. The entire lagoon, including Venice, is increasingly at risk from rising sea levels and increased storms caused by the climate crisis.

Hunter, who speaks fluent Italian (a legacy of his language studies at Oxford), was guided through the lagoon by Andrea D'Alpaos, a leading expert on the ecology of the Venetian salt marshes. “He took me out on a really cold January morning in this open boat through the marshes. An hour-long trip. He told me a lot about them along the way, and the cumulative effect of these anecdotes and being in the marshes made the seemingly unremarkable tufts of grass – because it was January, there were no flowers in bloom – seem like the most precious, sacred ecosystem.”

Hunter's varied creative career, which includes experimental theatre, opera productions and a French-language album, is increasingly environmentally focused – although she is also currently developing an opera about 16 nuns executed during the French Revolution. She produced the film of Megan Hunter's climate dystopian novel The End We Start From, starring Jodie Comer and Cumberbatch, which was released earlier this year.

The challenge of the climate crisis, Hunter says, is that “the knowledge deficit model – the idea that if we know the facts, we will act” – does not correspond to reality. Hunter and her fellow scientists at Salt of the Earth are desperately looking for artistic interventions to motivate action. We need stories, she argues, to help people connect with nature. We can look at as much scientific data as we want, such as rising carbon dioxide emissions, rising global averages for heat or oceans, but we need to really experience how the crisis is changing people's lives. “Good storytelling connects people and creates empathy,” she says. “Only when you engage emotions can you move to something active.”

Is there a risk that fiction about the climate crisis will lose its impact because we are hammering a certain message into it? “Emphasis will definitely not help anyone, so I will not advocate for it. I don't think all art should be about the climate crisis, but I definitely advocate that the potential and power of storytelling, together with science, can inspire action. It is a very powerful tool.”

Skeptics may see the large-scale installations in Venice as a carbon-producing middle-class luxury. “Of course you question the money that's being spent on this,” Hunter says of the project. “The question has been asked, 'Why not just put the money into restoring the salt marshes?' But the scientists say, 'We need you as a voice to get people to make that connection.'” Hunter says she questions the emissions question “constantly,” offsetting but also trying to be “as carbon negative as possible.” The salt is recycled; the costumes are “archived.” “I've questioned greenwashing, and this is nothing,” she says firmly.

Criticising artistic appeals to save the salt marshes as the latest crusade of the luvvies (after the rainforest, saving the whales, etc.) is simply a waste of energy, argues Hunter. “I recognise privilege, but there is more to it than that. I will use a platform when it actually makes a difference. When the salt marshes are recognised, as I hope they will be, there will be tangible results and impacts on people's livelihoods.”

Hunter hopes the performance's collaboration with local activists in Venice will produce concrete results, including We Are Here Venice, which educates about the importance of the salt marshes, and The Tidal Garden, a research collective that works with chefs, scientists and farmers to develop new ways to produce salt marsh-friendly food in the lagoon. “We developed this piece with the criterion in mind: 'What are we doing for the community when we do it?'” Hunter says; the performance is even funding a PhD in salt marsh research at the University of Padua. Although the performance lasts only three days, Hunter plans to world tour the installation to sites near salt marshes around the world, including the UK, and collaborate with other local charities.

While Salt of the Earth focuses on heroines seeking to change our relationship with the overlooked salt marshes, Hunter was particularly inspired by female scientists and environmentalists: Rachel Carson, author of the groundbreaking novel Silent Spring; American marine biologist Sylvia Earle; and South American indigenous activist Nemonte Nenquimo, whose book she is currently reading.

Clearly her experience as a mother was also formative. One of Hunter's next projects is a television series about the life of Margaret Wise Brown, the American author of the classic children's books Goodnight Moon and The Runaway Bunny, which Hunter read to her boys. Wise Brown was a radical member of the “here and now” movement in children's literature and education, which had the foresight to look for the miraculous in the everyday and “take a cue from the children rather than imposing all this structure on them,” as Hunter puts it. “There's a sharp contrast between what we're dealing with today – the crisis of childhood, the atomization and disconnection and everything that's coming to light about social media and young children – and that urgent message from the 1940s and '50s, which is to connect with your child, to connect with each other.”

Hunter often returns to Carson, who once wrote that if she could give a gift to every newborn, it would be “a sense of wonder so indestructible that it lasts a lifetime.” Ultimately, Hunter wants to create works that help people rediscover the natural world, an act that is in itself wonderful and optimistic. “This idea of ​​connecting with the natural world from the beginning,” she says, “that's our hope.”