It is not as lonely at the top as it used to be. At least not for plants which, due to global warming, are increasingly finding habitats on mountain tops that were formerly reserved for only the toughest and most hardy species. Over the past 10 years, the number of plant species on European mountain tops has increased by five times more than during the period 1957-66. Data on 302 European peaks covering 145 years shows that the acceleration in the number of mountain-top species is unequivocally linked to global warming.