The world’s glaciers and ice sheets are changing. Observations of glacier velocity (speed of ice flow), thickness, length and area alongside measurements of climate help us to understand this change. We can monitor these changes via remote sensing (using data from sensors mounted remotely, on things like UAVs and satellites), as well as from in situ measurements on the ice surface taken during fieldwork.

Remote sensing allows us to measure and monitor large areas all at once. It also allows us to undertake repeat measurements at different time scales. Alternatively, in situ measurements of glacier mass balance allow detailed observations and some have been repeated for decades. These long datasets provide rare glimpses into the long term behaviour of glaciers under a changing climate.