Greening rates are sensitive to methodology and biology; comment to Sustained greening of the Antarctic Peninsula observed from satellites

Roland et al. 1 claim to provide evidence for a ‘greening trend’ throughout the Antarctic Peninsula region over the last four decades, based on satellite remote sensing data. However, the early period vegetation cover estimates do not match with the likely extent of vegetated areas in this region at that time, raising doubts about the magnitude of any greening trend. Furthermore, growth rates of mosses and higher plants in Antarctica are insufficient to explain the 14-fold green cover expansion claimed, and neither have such changes been observed at long-term monitoring sites or from field warming studies. The reported satellite time series analyses of the presented trend seems biased by satellite image availability, lack of consistency in the areas covered by imagery and processing pitfalls. Antarctic terrestrial ecosystems are indeed predicted to become greener with climate change, but at much slower rates than reported by Roland et al. 1 .