"Lyell Glacier has shrunk 62% over the past century and hasn't moved in years. It's a key source of water in the park, and scientists say it will be gone in 20 years."
"Climate change is taking a visible toll on Yosemite National Park, where the largest ice mass in the park is in a death spiral, geologists say.
During an annual trek to the glacier deep in Yosemite's backcountry last month, Greg Stock, the park's first full-time geologist, found that Lyell Glacier had shrunk visibly since his visit last year, continuing a trend that began more than a century ago.
Lyell has dropped 62% of its mass and lost 120 vertical feet of ice over the last 100 years. "We give it 20 years or so of existence — then it'll vanish, leaving behind rocky debris," Stock said."