His 2004 novel The Hungry Tide is based in his beloved Sundarbans, a delicate eco­system of mangroves and mud in the Bay of Bengal that has already been severely altered by climatic disturbance. And his book of essays, The Great Derangement (2016), explores why we are unable to grasp the scale and violence of climate change.

Now, Ghosh has released his ninth novel, Gun Island, which could be des­cribed as fictionalised musings on climate change. But dry and depressing this novel is not – far from it, in fact; the book is as readable and enjoyable as his other works, and even more likely to surprise.

The novel reads as a detective story, although when I speak to him later on the phone from rural Goa, Ghosh insists this was not something he planned: “I just blunder along and I go where the story takes me. This means a lot of waste and unfollowed leads, but this is how I write.”

In the novel, Deen Datta, a dealer of rare books who is on the cusp of retirement, becomes something of a post-colonial Indiana Jones as he is drawn into the mysteries of an extraordinary legend. Inspired by two cryptic lines of almost-forgotten poetry and strange symbols etched onto the walls of an ancient temple guarded by a king cobra, Deen follows in the footsteps of the Bonduki Sadagar, or Gun Merchant, as he travels from the Sundarbans to Venice pursuing – or is he being pursued by? – an ancient goddess, Manasa Devi, the ruler of snakes.

Along the way, Deen meets love interest Piya, a fellow Bengali-American who has dedicated her life to studying the endanger­ed Irrawaddy dolphin. Then there is Tipu, a young man who forces Deen to confront the realities of life for young Indians, and his friend, Rafi, who pays a heavy price for an act of kindness. Cinta, an old friend of Deen’s and an expert on Venice, links these characters in a story that wraps India, Europe and America – and everywhere in between – in a tale of greed and grace, science and the supernatural, and man and the global machine.

The book has been described as the first literary novel about climate change, but Ghosh is quick to point out that it is no such thing – although considering the magni­tude of the issue, there is a shocking lack of imaginative literature on the subject.

The work is about acceleration – the result of our delusional quest for ‘progress’ – and the effects it has on people’s lives and the environment.

“More than 50 per cent of [the planet’s] greenhouse gases have been released into the atmosphere in the last 30 years – exactly the period of this incredible acceleration that we can see in every aspect of human activity,” Ghosh says.

“Goods are being moved and assembled around the world at lightning speed in the logistics revolution, made possible by the internet; news and information flows non-stop; people are moving in vast num­bers […] we can’t imagine it will leave lives unaffected,” he says.

Tipu and Rafi, fleeing trouble at home, become themselves goods shipped on trucks from illegal immigrant “warehouses” across the Middle East to Europe. But not all migration in the novel is to the West: within India and Bangladesh, following the devastating Cyclone Aila in 2009 – a real-life freak storm – desperate migrants flee to cities and are forced to become sex workers in their home nations.

“The great majority of migrants move within their own country,” says Ghosh. “In central India, we have examples of half a million people abandoning their homes every week [because of] drought and heatwaves. We see headlines of Indian fishermen being arrested in Iran and Pakistan as they are fishing out of their coastal waters. Fish stocks are so depleted they have to take their boats farther and farther afield.”

Like any novel, Gun Island is fiction, but “everything in it is based on some aspect of reality”, says Ghosh. Even the ending, which will come as a surprise to many (something truly unexpected, possibly impossible, occurs), is a reflection of reality.

“You can’t expect a novelist to explain away the ending of his book,” says Ghosh, with a chuckle. “But let’s just say we’re living in a time of all sorts of strange intersections of behaviour among human beings, and among animals. Nothing is implausible any more. Climate change is causing extreme occurrences, and all kinds of phenomena that are not always explain­able by the standards we once applied are revealing themselves.”

For Deen, whose Gun Merchant is revealed to be a man seeking meaning in his own time of climate upheaval – the Little Ice Age of the 1600s – liberation comes from looking back; “the possibility of our deliver­ance lies not in the future, but in the past, in a mystery beyond memory”.

“A standard trope when writing about the unknown we face today is to project into the future,” says Ghosh. “But we can’t see into the future, all we can look to is our human past, to earlier periods of catastro­phic change. If we’re going to pin all our hopes on the future, then we must also look to our past.”

Author Amitav Ghosh’s epic trilogy ends in Hong Kong

The novel also touches on a time when life moved much more slowly, and we com­mu­ni­­cated more widely, with gods and god­dess­­es, animals and plants, and ghosts of the past and the future. A time of folklore and the fantastic, before we looked at our natur­al environment through eyes that see only how we can package it for our own ends.

“I don’t consider myself an expert in solutions, nor do I think a novel is the place to discuss solutions. But if we think about why these things are happening in the world, it’s clear that we have become blind to our surroundings, that we are no longer able to understand the exterior world in the way that our ancestors did,” says Ghosh.

“We see everything around us as things to be used by us. Our ancestors didn’t see the world that way, and it’s clear that they were right and we are wrong. My novel is ultimately asking the question: how do we, once again, see and hear the world around us?”