Kathleen Jamie’s latest collection, Cairn, is slender – a mix of short prose fragments and a handful of poems – but do not make the mistake of supposing it slight. This marvel of a book is a profound meditation on the precariousness of the planet, braided to a personal sense of impermanence, not least in those pieces written as she edged towards her 60th birthday: “I can imagine the world going on without me, which one doesn’t at 30. Or shouldn’t.” This is a book where you keep encountering perfectly judged images such as this one: “Suddenly a crowd of white butterflies was fluttering around me like a shredded contract” that make one sigh with pleasure. She is an unshowily inspired writer.

The book is titled Cairn because it is made up of discrete pieces piled up together to form a whole – a landmark. The tone is an unforced mixture of conscience, wryness and heart that comes across as unmistakably and triumphantly Scottish. This is underpinned by Jamie’s lifelong love of the Scottish landscape. Her opening piece, Northern Isles, is about how her way of seeing has changed and traces the slippage from innocence to experience (she takes an unreasonably dim view of the poetry of her youth, chastising herself for being a romantic). The book is part diary, part appreciation and, by implication, part SOS. She is vividly undeceived about where we are now, recognising, in The Bass Rock, that nature is no longer uncomplicatedly a poet’s best friend: “It’s a while since we could turn to the natural world for reassurance, since we could map our individual lives against the eternal cycle of the seasons, our griefs against the consolation of birds, the hills.”

These pieces kept bringing tears to my eyes, catching me off-guard. She skilfully shows us that everything is affected by our awareness of the fragility of our planet and the potential for doom. June, somewhere between prose and poetry – the form is perfectly suited to an in-between moment – is a description of clearing out her parents’ bungalow with her siblings after their deaths. They are lightly amused by souvenirs that have been slumbering in the attic – until the mood changes:

“…Doulton figurines! Lasses trigged out in velvet gowns, poke bonnets, ermine muffs and … Ermine muffs?! – which set us off again, giggling as we passed round ‘June’ with her lovely posy and the handle of her parasol snapped off, then, bonny in ruffles and pinks, out came ‘Summer’s Day’ herself, but wildfires were raging, incinerating birds’ nests, torching toads and snakes –

And suddenly it wasn’t funny any more. Suddenly we
were greetin’ for everything we’d known as bairns,
all of it, everyone,
dear god even our summer days.

It is the mix of the conversational – that “dear god” – along with the sure pacing that is moving. And as she is ambushed – engulfed by loss – we join her, feeling our version of the same. It is what art or, in this case, wonderful writing can do.

Jamie never strains for effect. The quieter her voice, the more penetratingly it reaches us. She is relaxedly conversational while, as a poet, she has perfect aim. This beautiful book is an accumulation of moments that includes the sighting of a whale in December, the painting of a yellow front door during the pandemic, an afternoon walk in which “the eastern sky looks smooth and pale as a well-sucked mint”. And she allows hope into her conversation with and about nature, wondering in The Summit: “How can we make a world? If it is ours to dismantle, it is ours to make.”

• Cairn by Kathleen Jamie is published by Sort of Books (£9.99). To support the Guardian and Observer order your copy at guardianbookshop.com. Delivery charges may apply