America's National Parks: Canaries in the Climate Change Coal Mine

"The house of America is founded upon our land and if we keep that whole, then the storm can rage, but the house will stand forever." – President Lyndon B. Johnson

Despite the easy association of American culture with prosperity and modernity, historically, it was America’s National parks that were seen as a reflection of national character, as well as national priorities.

Travel to America’s National Parks, and you are quickly reminded that it is not our wealth, not our cars, not our designer boutiques, our high rise buildings or our suburban homes that define America. Rather, as so many have said, it is these parks that are the crown jewels of our country.

I was reminded of this over the last two weeks as I hiked through the lunar landscape of Utah’s Capitol Reef National Park and the pine forests, streams and crystal blue lakes of California’s Yosemite National Park.

But I also learned something new and disturbing: All is not well in America's National Parks, where the impacts of climate change are already apparent, not only where I hiked, but in parks all across the nation.

The idea of a National Parks system began in the mid-1800's and today, there are National Parks in every state except for Delaware. This fall, you'll be able to watch a 12-hour series on PBS that chronicles the people and policies that created and protect the park system. Made by the award-winning documentary filmmaker Ken Burns, the series took 6 years to make. Burns gave it a simple and true title: The National Parks: America’s Best Idea.

But off screen and on the ground, here's what I found out about our National Parks myself: the park system may need protecting from more than careless tourists with matches and drill happy politicians, but also from America's fossil-fueled prosperity and modernity.

Trees in Yosemite are Shrinking

Last week, the US Geological Survey (USGS), part of the Department of the Interior, announced that large trees have declined in number in Yosemite National Park during the 20th century, and they believe that warmer climatic conditions may be playing a role.

The number of large diameter trees dropped 24% between 1932 (the earliest records available) and 1999. This is of consequence not just for trees. It also means habitat loss and adverse affects for species including spotted owls, mosses, orchids and fishers (a carnivore related to weasels). It also is causing a decline in the overall number of trees since large diameter trees are a seed source for new trees and also tend to be more fire resistant. Data from another National Park --  Sequoia and Kings Canyon --  home to some of the world’s largest trees, are showing similar trends in declining tree diameter.

“Although this study did not investigate the causes of decline, climate change is a likely contributor to these events and should be taken into consideration,” said USGS scientist emeritus Jan van Wagtendonk. “Warmer conditions increase the length of the summer dry season and decrease the snowpack that provides much of the water for the growing season. A longer summer dry season can also reduce tree growth and vigor, and can reduce trees’ ability to resist insects and pathogens.”

Wagtendonk said that he has been criticized for speculation but told me “I stand by everything I said.” Later he explained why he feels it is important to make the connections.

“These data are important,” he said, “because it does indicate that changes are occurring in places that are held near and dear by the public. People don’t relate what they do in their personal lives to its impacts on the National Parks but what happens in the Bay Area or Los Angeles affects us here.”

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