The high Himalayas are a forbidding place to eek out an existence. Only highly specialized organisms can adapt to the frigid conditions. So you can imagine the surprise when researchers ascended more than 20,000 feet and stumbled upon some greenery.

Mosses and algae are known to grow at altitudes this high, but this was something different: a vascular plant; a cushion plant, to be exact. In fact, there were six different species of them, all clinging to a small, gravelly, southwest-facing patch of land on Mount Shukule II, in the Ladakh region of India. The tiny community of vegetation now represents the highest plants ever discovered, surviving at an altitude over 20,175 feet, reports New Scientist.

Researchers learned that the plants had evolved features to survive in the cold, variable conditions that exist at that altitude. Each was no bigger than a coin, had leaves arranged to help them enfold warmer air, and possessed a high-sugar antifreeze. Even with these adaptations, however, it's unlikely they could have survived here without help from retreating glaciers and global warming.

According to researchers, the average temperature in the short growing season at this spot has already risen by around 6 degrees Celsius in a decade. As temperatures continue to climb, so will the plants. The only real limiting factor for them is the cold temperatures; plants need at least 40 days of frost-free soil each year in which to grow.

β€œIn the arid Himalayas β€” mostly Tibet β€” there are many mountains with vast unglaciated areas available,” explained Jiri Dolezal, team leader on the expedition.

That might sound like good news for plants, but as the tree line ascends, these specialized alpine species begin to run out of habitat. The mountains only go so high. So critical ecosystems are in peril, even as they climb ever higher.