Sierra Summit

Conversations and observations about California's mountains

September 30, 2008
Climate Change bookshelf - recommended reading
Want to know more about climate change from someone who knows the subject inside out - and past and present?
Pick up the latest book by Wallace S. Broecker (co-authored by science writer Robert Kunzig) - Fixing Climate - What Past Climate Changes Reveal About the Current Threat - and How to Counter It.
Broecker is one of America's most highly-regarded climate scientists and the Newberry Professor of Earth and Environmental Sciences at Columbia University in New York City. What's intriguing is how much much of his interest in the subject stems from early field trips through California's eastern Sierra Nevada and parts of western Nevada. On those trips to Pyramid Lake north of Reno, Mono Lake near Lee Vining and elsewhere, Broecker began to realize how quickly past climate regimes changed - from ice age to warm spell, from periods of ample rain and snow to century-long "mega-droughts."  Such past turnabouts were brought about by natural causes. But with CO2 levels from fossil fuel burning now contributing to the warming the planet, Broecker says we are now changing the climate ourselves - and the results may be dramatic once more. 
"The message from the study of past climates is that the time for stopping the increase in atmospheric CO2 is now," Broecker and Kunzig write in the book. "Skeptics often find strange solace in the knowledge that climate varies naturally, as if that somehow disproves that fact that we are rapidly changing it ourselves, or as if it somehow implies that climate change is inevitably benign. 
"When you have explored the Ice Age ... and especially the wild swings that happened within the Ice Age, you don't think natural climate variability is benign."
Fixing Climate was published this year (2008) by Hill and Wang, a division of Farrar, Straus and Giroux. 

September 12, 2008
Journal of Forestry article now online
In a recent blog, I wrote about an important new article about climate change in the Journal of Forestry, the most widely circulated scholarly forestry journal in the world. 

But there was a problem - the article was available online to subscribers only.  

Now you can read it for yourself. 

My thanks to the Society of American Foresters ( which publishes the Journal, for making this happen. And without further adieu, here's the piece (remember to click on View Now - PDF tab once the page opens):

September 4, 2008
New Climate Study: Warmest in 1300 years
A new study published online by the Proceedings of the National Academy of Sciences provides more data indicating that temperatures across the northern hemisphere are now at a record high.

The authors compiled historic surface temperatures from tree rings, marine sediment, ice cores and other sources and concluded that temperatures over the past 10 years are higher than at any time in the past 1,300 years. It's even warmer today, the authors say, than during the Medieval warm period when the Vikings colonized Greenland. 

You can read the paper at:

For an summary of the paper by the PNAS, go to:

Thanks to - an environmental news service - for posting a story about the  study at:
September 3, 2008
Dry times, downed trees and climate change
Not many people spend more time outdoors in northeast California than Jay Fair. An 84-year-old fishing guide, he knows just about every back road - and every trout fishing lake - across the lonesome high desert region. 
This spring, I spent a day with Jay and asked him about global warming and climate change. 
 "I can see it," he told me. "All of our desert lakes are drying up. How can you possibly deny it? All you got to do is look around. 
"My goodness, I started fishing Eagle Lake 35 years ago and it's down over 12 feet. I see a drought everywhere. We're into it and we're going to suffer from it."
Jay grew up in New Mexico in the 1930s during the Great Depression and the Dust Bowl. He knows dry times.  And what he sees on his travels across the back-country worries him. "There's a huge lake right behind us," he said outside the small town of Madeline. "It's four feet lower this spring, during the run-off time, than it was last fall."
There's something else that troubles him, too  - large swaths of juniper trees, some centuries old, that are being logged on public land to shred into wood chips to burn as green energy in power plants . It's all part of a federal program to restore the land to pre-European ecological conditions. 
But Jay and his son Glenn believe that in an age of climate change, California needs those trees for carbon sequestration and other purposes. ""If we're not careful, we're going to do everything we can to get energy and just devastate the planet," Jay said. 
Watch for my report from northeast California on junipers, carbon and climate change in an upcoming issue of the Bee. 


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

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