Most of Britain’s landscape has been shaped in one way or another by ice.
During the past 2.5 million years our climate has fluctuated between cold glacial phases and warmer - interglacial - phases. Each cold and warm cycle lasts around 100,000 years.
During glacial phases, temperatures across Britain fell more than 8 degrees lower than present. Ice sheets and glaciers covered much of northern Britain and at their most extensive reached as far south as London and Bristol.
We are in the latest warm phase at the moment, a ‘phase’ that has so far lasted 10,000 years.
More than 25 of these cold to warm cycles have occurred, the trigger for them being very slight and regular changes in the Earth’s orbit around the sun.
This hummocky landscape, dusted with snow and crisscrossed by stone walls, is a reminder of Britain’s icy past. Unlike the deep valleys eroded by glaciers, such as in Glen Tilt, this landscape is made up of the debris dumped by glaciers and ice sheets as they repeatedly advanced and retreated across lowland areas.
Sometimes debris was left simply as an irregular hummocky mass. At other times it was shaped and moulded by the ice flowing over and around it into egg-shaped hills - called drumlins. Or it was piled up into ridges marking, for example, the former edge of the glacier. The Cumbria lowlands are a particularly good place to see such features.