Riding through thevalleys, we are soon reminded of the historic industrial heritage of coal mining communities that only closed some 30 years past.

Bullough is convinced that adapting to the climate crisis depends not simply on technical fixes but on new stories and principles for how to live better with the natural world.The poetry of Bullough’s writing is ever present, mirroring rivers, rolling farmland and high, rocky ridges, ‘its stream weaves, tumbles over glistening falls, between broad pebble beaches and banks of red soil topped with clusters of yellow welsh poppies’. Transport to and from either end is made most simple by train, with stations in both Swansea and Conwy, although there is not a direct link between the two. He explains that in September 2020 he was arrested and charged for refusing to move on from Parliament Square during the Extinction Rebellion protest. My second day’s trek is a long one – I slog 18 miles across the Beacons to reach the town of Brecon. Age and experience come into it, no doubt, but the change I mean is a wider change, the (very slow) awakening of society at large to the single, central question: how do you make sense of yourself in the face of the Climate and Ecological Emergency (CEE)?

Perhaps because I am alone, with just mountains and slick cobbles for company, it’s easy to conjure up the platoons of Roman soldiers who tramped this way before me. Built by the Romans, it ran all the way up Wales, from Neath near the south coast to Caerhun in the north.The transformation of landscapes and our society “is a revolution beyond anything that anyone in this part of world has ever experienced,” he says. Photograph: Aled Llywelyn ‘We think this is nature, but it’s a skeletal landscape ultimately’… Tom Bullough. From here we have a stunning view of Bannau Brycheiniog (Brecon Beacons) with Penyfan standing proud and tall.

The route then passed through Dolwyddelan, running through the Cwm Penamnen valley and past the higher parts of Cwm Penmachno. Christianity took hold in Wales so strongly, he argues, because it fitted its values and places of worship into pre-existing religious systems. He discusses the environmental crisis which we are facing through his connection to the landscape; and in the process making the coming catastrophe much more relatable. You can take your bike on these trains, but do check if you need to make a reservation for your bike when you book your ticket.You’ll need a mountain bike with wide, grippy tyres and a good range of gears to navigate Wales’ steep hillsides and the many sections of technical trail that you’ll find along the route. Part of the narrow-gauge Corris Railway between Aberllefenni and Maespoeth Junction may run along the line of the Sarn. It describes the walk that Tom takes along Sarn Helen, the Roman road that runs from Neath in South Wales to Llandudno in the North. Also cuckoos are a brood parasite, meaning they hijack another bird’s nest by removing existing eggs and laying their own. The road gives its name to the annual Sarn Helen Hill Race that starts and finishes in Lampeter in mid-Wales.