Sierra Summit

Conversations and observations about California's mountains

October 1, 2008
Sierra Nevada glaciers - going, going, gone?
greg re-do.jpg
Recently, I spent a few days in the field with Greg Stock, geologist for Yosemite National Park, checking on the health of the Lyell glacier, the second largest permanent ice sheet in the Sierra. Greg (left) told me many things about the Sierra's 100 or so glaciers, but nothing struck me more than his grim prognosis for them. "Given the amount of change we've seen even over the past few decades, I think it's safe to say that those glaciers will be gone in 100 years. They may even be gone in 50 years and there's a chance that some of them will be gone in 20 years," Greg told me. The problem, in Greg's view, is global climate change - in particular rising CO2 levels caused by the worldwide burning of fossil fuels that are causing temperatures to climb. This is not the first time that Sierra glaciers  have receded.  But this retreat is different. "I think the fundamental thing that makes the melting of today different than the melting of the past is that almost certainly humans are causing it," Greg said. Watch for my upcoming report in the Bee about the Sierra's receding glaciers and what Greg Stock and other visitors to Yosemite's high country have to say about them. 

On October 14, The Sacramento Bee will temporarily remove commenting from While we design the upgrade, we encourage you to tell us what you like and don't like about commenting on and other websites. We've heard from hundreds of you already and we're listening. Please continue to add your thoughts and questions here. We also encourage you to write Letters to the Editor on this and other topics.

About Sierra Summit

The Author
Tom Knudson lives in the Sierra Nevada and travels widely throughout the range. His hobbies include fly-fishing, backpacking and cross-country skiing. He is the recipient of numerous journalistic awards, including two Pulitzer Prizes, one for a 1992 Sacramento Bee series "Sierra in Peril," a watershed work about environmental threats to the mountain range. E-mail Tom at

Visit's Sierra Warming section

October 2013

Sun Mon Tue Wed Thu Fri Sat
    1 2 3 4 5
6 7 8 9 10 11 12
13 14 15 16 17 18 19
20 21 22 23 24 25 26
27 28 29 30 31