Climate Change and the Sierra Madre Occidental

Op-Ed: With climate change, we may witness sequoia forests convert to chaparral

By Jeff Masters

For a century following its discovery, the Sierra Madre Occidental was a place of great beauty: towering redwood and giant sequoia trees, a great mountain lake with a wide stretch of beach and an area of rugged cliffs and gorges. But in the past three decades, the forest has become the poster child for what is happening to our planet’s most sensitive ecosystems.

This year, more than 3,500 square miles of the nation’s fastest-warming ecosystems will get more than 2 degrees higher in temperatures and 1 degree higher in annual precipitation, according to an analysis by the National Oceanic and Atmospheric Administration and the California Department of Water Resources. That represents the combined effects of rising temperature and precipitation across the western United States and the southeastern border of California.

The increase in drought in California has been especially troubling because of the historic drought, which lasted from 2003 to 2005, to which California is a major contributor. That drought was caused by a combination of climate change, population growth, and reduced snowpack from warming temperatures.

The combination of this year’s drought and heightened climate change conditions will put the Sierra Madre at risk for an extraordinary drought in 2018 to 2018 and possibly in 2019, said Tim Livesey, a scientist with the U.S. Climate and Weather Program.

“When you’re talking about a 2-degree change in temperature, you get a 2-degree change in precipitation,” Livesey said. “The average temperature is going up nearly 2 degrees for California, but in the Sierra there’s already a 2-degree increase in temperature, and with that the average precipitation, that’s a 5-foot increase in precipitation. A 5-foot increase is going to put a lot of stress on the Sierra Madre as far as being able to provide the water to support the trees and the shrubs that provide food for the animals.”

The Sierra Madre is already experiencing these effects at three different scales.

At the national scale, the Sierra Madre Occidental is the second-driest region in the contiguous United States and the driest area in the western hemisphere, according to Climate Central. This means that the region is experiencing

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