Otherworldly ... a Quiver tree forest (left) and Chelsia overlooking Fish River Canyon.

This is weird - it feels as though I have stepped onto a film set for some alien science fiction movie. The sense of the unreal starts at the border crossing between South Africa and Namibia. I hand the immigration officer the slip of paper the border police have given me. He reads it, then stares hard at me.

"This says one person," he says. "Yes," I say. "You travelling alone?" "Yes." "You are a woman?" "Yes." I would have hoped at least that much was obvious. He pushes back his chair, and scrutinises me again. My heart is pounding and my legs turn to jelly, and I feel guilty of every crime ever committed: here's where I get searched, detained, locked up for life. Is there a British High Commission in this deserted place? But he shakes his head, stamps my paper and sends me off to the customs, the police, the road tax charge office to get all the squares on my paper duly stamped - it would have been quicker playing Bingo. Then an hour later I'm on my way in Namibia, and the desolation starts immediately.

The landscape is surreal: huge boulders stack up into mountains and the black soil is littered with ghostly tufts of white grasses. Miles and miles stretch out flat and unvaried before me, with not the slightest sign that humans have ever passed this way, save the road I'm travelling on. A dried thorn bush mysteriously scurries across the road, and I'm not sure if I should break to let it pass.

Then the Fish River Canyon - huge, gouged out like an unhealed wound, and breathtakingly beautiful in its desolation; and the Devil's playground, where for several square miles the rocks are stacked up so precariously it seems like some immense child has had a tantrum in the toy cupboard; and the weird Quiver trees stretching for acres like the flailing arms of invading aliens, and throughout all this the sense of arid desolation. This is like no other place on earth.

I find I am learning new skills - like driving on a gravel road, where the least corrugated track is the one to take, regardless of which side of the road it is; like timing my activities to the hours of daylight. I have been staying in remote campsites, where the provision is basic, to say the least. Electricity is an unheard of commodity, and if my tent is not up before the sun sinks, I have a problem. Complete darkness arrives about half an hour after the sun sets, and my torch batteries have to be conserved for emergencies, as I'm not sure when I will reach civilisation again to replenish them. The hours of darkness are for sleeping only, and I have done so much of that lately I wish it were bankable against a hectic city life. I am also learning to discern night sounds - the barking is baboons around the campsite looking for food - I was grateful for the tip to leave all food locked in the car boot. The strange howling was a jackal, but he would be unlikely to come too near the camp. But the chomping right next to my ear was just a sheep munching at the thorn bush I had chosen to give me some shelter from the wind.

I am also learning to cope with the erratic temperature. The days are warm and dry, but the moment the sun dips the temperature drops dramatically and has been around zero every night. This morning I woke with wet hair - the condensation had been so great that it had seeped through the skin of my tent and soaked my head which was touching it. I have had to invest in a blanket - not what I had thought I would be doing in my desert trip!

There is a different sense of calm here - a tough calm, born from secure local knowledge and confident ability to cope with harsh conditions and survive. This is a very long way from the gentle blue and green calm of the Sarek. I am finding the contrasts I sought, and this is learning indeed.