Rapid change in East Antarctic terrestrial vegetation in response to regional drying

East Antarctica has shown little evidence of warming to date with no coherent picture of how climate change is affecting vegetation. In stark contrast, the Antarctic Peninsula experienced some of the most rapid warming on the planet at the end of the last century causing changes to the growth and distribution of plants. Here, we show that vegetation in the Windmill Islands, East Antarctica is changing rapidly in response to a drying climate. This drying trend is evident across the region, as demonstrated by changes in isotopic signatures measured along moss shoots, moss community composition and declining health, as well as long-term observations of lake salinity and weather. The regional drying is possibly due to the more positive Southern Annular Mode in recent decades. The more positive Southern Annular Mode is a consequence of Antarctic ozone depletion and increased greenhouse gases, and causes strong westerly winds to circulate closer to the continent, maintaining colder temperatures in East Antarctica despite the increasing global average. Colder summers in this region probably result in reduced snow melt and increased aridity. We demonstrate that rapid vegetation change is occurring in East Antarctica and that its mosses provide potentially important proxies for monitoring coastal climate change.