The stems of shrubs have given researchers a window into a glacier’s past, potentially allowing them to more accurately assess how they’re set to change in the future.

Their findings have been published today, 27 November, in IOP Publishing’s journal Environmental Research Letters, and show how a glacier’s history of melting can be extended way past the instrumental record.

Much like the rings on a tree stump indicate how old it is, measuring the width of rings on the stem of a shrub can give a good indication of how well it has grown year on year. Under extreme environmental conditions, such as those close to a glacier, a shrub’s growth relies heavily on summer temperatures, meaning the ring-width of a shrub can be used a proxy for glacial melting, which also relies heavily on summer temperatures.