Sierra Nevada glaciers - going, going, gone?

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.  Read Full Article