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
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