At the edge of the moor, there’s a knot of birch that over the years has become familiar to me – not for the trees themselves, but for the earth that nourishes them. Here the ground turns to a peaty gloop and the path braids as walkers explore different ways to keep their boots out of the mud. Not today, though. Today the ground is iron-hard and has been for a week, with daytime temperatures remaining at or below freezing. I can walk where I want.

Freezing soil has lots of benefits, some of them magical. For example, the earth beneath my feet has become a kind of time machine, preserving the foot and hoof prints of animals and people that came this way days ago. Among the prints are those of red deer; looking up, I see two hinds 50 metres away, breath condensing against the cold air. I’m tempted to ask: “Was this you?”

Yet it’s what freezing does to the soil itself that intrigues me most. Gardeners know that hard frosts can add structure and kill unwelcome pathogens, but that doesn’t come close to the complexity beneath my feet.

A handful of soil seems beyond comprehension, containing as it does multitudes – billions of single-cell organisms from tens of thousands of different species, strands of fungal mycelium that separated out would stretch for kilometres. If all this died, then we would follow in short order.

The problem being, of course, that “all this” is dying, and climate change is playing a role in that. When we see flowers blooming at the wrong time of year, the impact of the changing climate seems real. We cannot see how rising temperatures are reducing the diversity of bacteria in the soil, but it’s happening, and it’s even more ominous.

It says something about our species that we know a lot more about how freezing soil impacts engineering projects than we do about its role in the microbiome. So, I rejoice for today’s hard ground. We need the cold more than we know.