You have to be pretty hardy to flourish in the Arctic, and those plants that do tend to live just a few centimetres above the ground. But the cold north in recent decades, has seen some of the fastest rates of warming on the planet and the flora have reacted accordingly.

It's not just that existing shrubs and grasses have increased their stature, although that is the case, but rather that taller species are now moving into areas they never used to grow in large numbers. This shift has repercussions, an international team reports in the journal Nature. Taller Arctic plants trap more snow around them, insulating the ground from cold air. And that'll speed up the thawing of permanently frozen soils, releasing their carbon into the atmosphere. It's a feedback that should further warm the climate.

Isla Myers-Smith from the University of Edinburgh says that on current trends, the centimetres-tall Arctic plants could double in size by the end of the century. What sets this study apart is its scale – more than 60,000 plant measurements all across northern latitudes. And that's just the modern data – the research also lent on decades of previous observations.