Day Four begins unsteadily in Bordeaux, perched on a high chair like a stork wobbling over breakfast. From this precarious throne comes conversation -  Americans, Canadians, Scots, one Englishman. Politics rises, as politics does, and for once agreement is universal - America is in turmoil, the media is unreliable, and climate change is the storm that no one is preparing for. The North Americans boast their use of trains and buses to cut carbon, which makes my Audi Q5 feel a touch extravagant - though they did, of course, fly to Europe.

The road south is crowded and alive. The Garonne River still shows scars of recent floods, pillars marked with three metres of water. Lorries dominate the autoroute - Lithuanian, Belgian, Spanish, Portuguese, Ukrainian - a procession of freight that explains why transport guzzles a quarter of Europe’s emissions. The cars are mostly solitary drivers, the fields mainly maize and stubble. In Spain, the fields shrink, sunflowers blacken, and among the conifers brown patches spread - drought, disease, decline. Logging trucks trundle past with healthy trunks stacked like casualties. For me, chainsaws are the sound of sorrow.

Not all scars are natural. Banners of anti-tourism and anti-immigration hang from bridges, reminding me that travel is not only about distance and fuel but also about identity, politics, and belonging. The road is clean, tolled, well kept - so unlike Britain’s free but battered motorways. Basque hills roll green and layered with history, road signs shifting between Spanish, French, and Arabic script.

And then the Castilian plateau opens - vast, treeless, shimmering. Wind turbines turn, solar panels glitter, Spain quietly reminding the world that 57% of its power now comes from renewables. Yet the petrol stations tell a different truth - dozens of pumps, four lonely chargers, fossil fuel still king. Even the saplings wear plastic guards, a supposed promise of green growth that carries its own plastic curse.

By Burgos, the River Arlanzón runs swollen and brown. Plane trees along its banks wear a dusting of mildew, a symptom of hotter days and damp nights - exactly the pattern climate change encourages. Black poplars stand proud, willows lean gracefully, but the story is clear - disease, drought, and flood are the new rhythms of European riversides.

Burgos Cathedral rises, a stone testimony to another era of environmental impact -  medieval ambition stripping forests and quarries to erect a Gothic giant that still draws crowds. Beautiful, yes, but crowded, noisy, hard to find quiet in. The Museo de la Evolución Humana is closed - it is Monday - but its presence whispers the deeper story of Atapuerca, of how we have always been travellers, always migrants. The difference today is speed, scale, and consequence.

Why listen? Because this is no glossy road-trip podcast. It is a journey that notices the lorries, the brown trees, the mildew on plane leaves. It sees renewable triumphs and plastic failures, Gothic glory and environmental cost. It shows Europe not as a postcard, but as it is - fragile, contested, shifting under the weight of climate and change.

Why not listen? If you want escapism, this isn’t it. There are no smooth filters, no tidy endings. Instead, there are chainsaws, traffic, tolls, mildew, and awkward truths. This is travel seen through a field surgeon’s eye - unromantic, sometimes unsettling, but always real.

Day Four ends in Burgos. Tomorrow, the road pushes on towards Madrid. More lorries, more fields, more questions. And perhaps, a few more answers.