Scientists have been watching 1,000 species of mountain animals and plants around the world to see how they react to a warming climate.

They’ve found that as annual temperatures climb, many species have climbed, too. On average, for every one-degree-Celsius increase, mountain-dwelling species shifted 100 meters upslope.

Because the mountains narrow as they go up, this means a shrinking habitat for those species, and often a dramatic drop in population.

For instance, butterflies in the French Pyrenees and gophers in Nevada’s Ruby Mountains have lost 70 to 80 percent of their range, as suitable habitat shifted up the slope.

Birds on one mountain in the Peruvian Andes moved 250 meters up over the past 30 years in response to a change of just one degree.

Some of the migrating species are soil microbes, which, as they move upslope, may allow tree species to move up with them. In these cases, the treeline could rise, supporting forest species on their upward climbs.

But as the climate continues to warm, earthbound species like trees, crawling insects, and mammals will eventually run out of mountain. If they can’t adapt to the warmer temperatures, they may die out.

Birds and flying insects would be able to fly to higher ridges and mountaintops—as long as there are higher ones in the region.

Regardless of cause, these are effects we can measure and observe today: plants and animals the world over are migrating to adjust to a warming climate.