KATHLEEN Jamie drags her finger in a jagged line along her red, V-necked sweater. "What I have is a mastectomy scar that runs from here to here," she says in the understated tone that characterises her speech and, very often, her writing.

Jamie is showing me the book she produced about her experience of cancer. As fans of her work will anticipate, Frissure is not a forum for personal revelations and private epiphanies, but an attempt at transfiguration which leads her from “fear and loss back into the beautiful world.”

Her response to her mother's death was to visit a pathology lab and direct her forensic, unremitting gaze at a tumour. So there's a symmetry in her decision to subject her own wound to the scrutiny of artist Brigid Collins, who turned it into the stem of a rose, the shoreline of an island, a river.

By the time Jamie sat for Collins, her body had already been objectified. "I don't know if you have experience of being under medical attention – but attention is the word," she says. "They don't half look at you, with this medical gaze. I was interested in that, the way the surgeons were looking. I admired it."

Jamie's ability to look and listen, and then to communicate what she sees and hears with clarity and beauty, are the hallmarks of her very particular genius. Though often referred to as a "nature writer", she defies categorisation. What she does in her essay collections – Findings, Sightlines and now Surfacing – is to bear witness; to notice things the less keen-eyed might miss, such as a ship reflected in a train window. And hopefully make us more observant.

Surfacing is about excavation, literal and metaphorical. The two longest essays describe sites in a Yup'ik village in Alaska and Links of Noltland, Orkney. She is both archivist and archaelogist, unearthing artefacts and memories, digging, as Seamus Heaney would have it, with her pen; but also scattering new fragments, like broken china, for future generations to sift through and interpret.

As in her earlier collections, the language in Surfacing corruscates. Images – of "villages like glowing gems spilling down barren mountainsides" and of an eagle moving like "a puck sliding over ice" – are treasures to be turned over in one's hand and held up to the light.

Yet there is a subdued tone to Surfacing; not jaded exactly, but weary; and a sense of being unmoored. At 57, Jamie's parents are dead and her children are moving on, prompting her to reflect on lost time. In From the Window, a piece about her daughter leaving home, she looks out at the near-white sky, and wonders: "What now?"

I meet Jamie in the flat in Edinburgh where she has been staying in the wake of her Book Festival appearance. She has told me she is dreading this interview, so I am uptight. The tourist-thronged streets through which I am walking are not helping.

Jamie seems similarly discombobulated. "I am at that stage where I am thinking: 'Ok, I could have another 30 years, what am I going to do with it?'" she says. "I thought it would be empty and easy, but it isnae; there's just more nonsense."

This "nonsense" refers, in part, to the turmoil in the world: Brexit, climate change. "It's so difficult to concentrate now. If the Amazon rainforests are burning we hear about it within minutes on Twitter. Do we have a duty to keep up with everything even if it damages our minds?"

Climate change looms large in Surfacing. Is Jamie not in a state of perpetual fury? "I rarely feel anger,” she says. “What I am is aghast. I mean, how did we get here?"

She agrees Surfacing lacks the joie de vivre of previous work. "I don't think I could write Findings now," she says. "Something has changed. Is it me or the world?" Then, conscious of how bleak she sounds, she gives herself a shake. "But that would be terrible. The world is full of joy, full of wonder. We mustn't lose that."

In the first half of the 20th Century, "nature" writing was seen as a refuge. "The last nature book that was universally popular was Ring of Bright Water. It represented a retreat and possibly a fantasy because we now know Gavin Maxwell was not a happy man," she says.

Around the time of the moon landings, it went into abeyance; when Jamie started writing – first poetry, then essays – it was still unfashionable. Now, nature writing is where it's at; but these days it is less pastoral, more political.

"I think if you are proper 'nature' writer, you can't not be political," Jamie says. "It would be derelict, which is not to say you can't enjoy half an hour watching butterflies and bring that to other people. But you have to have an awareness or you are kidding yourself."

What form protest should take is one of the questions Surfacing explores. In The Wind Horse, which reflects on the months Jamie spent in a Tibetan town in 1989, Chinese art students challenge the government with "beauty, not politics.” Marek, a Czech student, dismisses this. The Wind Horse finishes with Jamie imagining Marek in Prague's Wenceslas Square during the Velvet Revolution.

“The Chinese kids got murdered, the Czech students brought down the regime, but it's not given to us all to be activists, or to chain ourselves to railings,” she tells me now.

Jamie's writing is not polemical, but during her appearance at the Edinburgh International Book Festival she described noticing as "an act of resistance". "We are living through a time of grotesque inattention,” she said.” The very act of taking heed is political.” Is that how she sees her own work, as an act of resistance? "It's not why I do it, but I would be delighted if others thought so."

Jamie was out of step when it came to form, too. In the UK, the essay had fallen out of favour. Today, it is also experiencing a "moment". Authors including Kevin Breathnach, Sinead Gleeson and Emilie Pine are in the vanguard of a millennial movement. These essays, though, tend towards the personal; all their collections contain painful revelations.

Jamie on the other hand is intensely private. When I ask her about this, she insists she has no painful experiences to mine. But she has the deaths of her parents, cancer, an early failed marriage. These she drops in almost as asides and pared of emotion. “I am not an emotional person,” she says. “Sometimes I think there's something wrong with me."

Jamie puts her lack of emotion down to her Presbyterian upbringing; she grew up with two siblings in Currie, Edinburgh. Her parents were not churchgoing, but they were determined to stamp out perceived self-indulgence. "If I got into a tizzy, my mother would say: 'Who do you think you are, the Queen of Sheba?' If I came flouncing into a room, she would say: 'Here comes a galleon in full sail.' Maybe it was about the importance of thinking rather than feeling, but it's a bit hard on a six-year-old."

It has stayed with her, this wariness of emotion. "There is so much emotion about at the moment. Less rationality, and people thinking their 'feelings' matter. I was just reading an article about people not getting their kids vaccinated because they 'feel' something. I mean, f**k off, you know?"

Jamie can be tetchy. She will halt like a horse refusing a fence when asked a question she doesn't fancy. Describing herself as “sleekit”, she doesn't like to be pinned down. Yet she can be expansive too. She is open about not having written a poem in five years, blaming the background noise and there being no words appropriate for the circumstances.

Later this year, she will take on the role of Seamus Heaney International Visiting Poetry Fellow at Queen's University, Belfast. She plans to shut herself away and focus on half-written poems. And after that? She doesn't know. She toys with the idea of returning to Pakistan, the setting for Among Muslims, her book based on travelling there in the early 1990s, then remembers that climate change dictates she shouldn't fly.

The last essay in Surfacing sees Jamie losing her way in the woods while thinking about "the guns, the wars ... the chainsaws, the sea creatures tangled in plastic." When she stops and focuses on her surroundings "green ferns in the groin of an oak. Green moss cloaking a stone", she realises she has over-reacted. "The path is at your feet, see? Now carry on," she writes.

Having completed Surfacing, Jamie seems directionless. But there is hope in that sentence. Just think what great new works might emerge when she is able to cut through the din and start noticing again.

Surfacing, by Kathleen Jamie, is out on September 19 on Sort of Books, priced £12.99.