Walk up a glacier in crampons, above where its ice ended thirty years ago

Sólheimajökull is an outlet glacier, a tongue of ice about eleven kilometers long running south-west off Mýrdalsjökull, the ice cap that sits on top of the Katla volcano. Up close it is not white. It is gray and black in bands, striped with old volcanic ash, and the surface is ridged and cracked rather than smooth.

Crampons go on at the edge, over boots, and the walking changes from the first step: the point of the spikes is that the ice can be trusted rather than tiptoed across. The route weaves between crevasses and past moulins, the round shafts where meltwater has drilled straight down through the glacier.

The part that stays with people is not the ice. It is the guide stopping partway up, pointing at a spot out on the moraine, and saying the glacier ended there thirty years ago. Everything between that point and the group used to be several stories of it.

The number behind that is roughly fifty to sixty meters a year. There is a lake in front of the glacier now that was not there in the nineteen nineties, and it grows by about fifty meters a year as the ice pulls back off it. Sólheimajökull is the only outlet of Mýrdalsjökull that ends in water, and it is the reason a walk on it is booked in the same tone as the ice cave: the thing is not going to be this shape for long.