There’s a cycle that starts when the snow melts and the earth thaws high in Colorado’s Rocky Mountains. It’s a seasonal cycle based on timing and temperature, two variables that climate change is pushing increasingly out of sync.
To the outsider, it can be hard to see: Plants still grow, flowers bud, bears awake, and marmots breed. Broad-tailed hummingbirds still trill around a landscape that evokes the opening scene of The Sound of Music, with flowery meadows and granite peaks.
But those who know this ecosystem will tell you something is a little off. The flowers are blooming earlier. The marmots are mating in early May. Spring is springing sooner across the Northern Hemisphere, changing natural cycles around the world.
In Alaska, brown bears are changing their feeding habits to eat elderberries that ripen earlier.
In California, birds are nesting and breeding a week earlier than they did a century ago.
“One of the consequences of climate change is that even though everything is happening earlier, they’re not changing at the same rate,” says David Inouye, an ecologist from the University of Maryland who has spent more than 40 years documenting the change in Colorado’s alpine meadows.
The results can be seen all around him. Flowers are blooming before there are bees to pollinate them. Hard frosts are still occurring long after winter’s snow melts away, decimating fruit orchards and budding plants. Allergy season is getting longer.
Inouye says that when he started spending his summers at the Rocky Mountain Biological Laboratory in Gothic, Colo., cataloging flowers in the thin mountain air, climate change wasn’t really a thing people were talking about. But as time went on, the evidence of it started to become unavoidable.
“Temperatures are getting warmer here,” he says. “The April low temperatures here are now about 6 degrees Fahrenheit warmer than they used to be.”
Some plants and wildlife, taking their thermal cue, have been able to adapt in kind. Some are thriving. Others are being left behind.