How might climate change affect California?

Average Temperature Plots

Visualize yourself for a moment, wandering the desert sands of the Mojave desert. You pass Joshua trees and fields of wildflowers as you head north to Death Valley. Sand dunes, rock canyons, and beautiful mountains greet you there. Heading west you find yourself in a forest of giant sequoias and soon are climbing over the Sierra Nevada Mountains. Eventually you find yourself at the coast, dipping your toes into the cool blue Pacific Ocean to sooth them after your long hike. You turn your gaze north and wander along the coast until you wind up in a coastal redwood forest. If you were to turn east, you might run into the once-active volcanoes of Lassen Volcanic National Park. Throughout your journey you would encounter a fabulous array of plants and animals, from forest to desert, coast to mountain, the species would change with the environment.

California is an amazingly bio-diverse state. A large part of the state is a global biodiversity hotspot designated as the California Floristic Province. This hotspot contains 2,124 endemic plant species, species that are found nowhere else in the world. The geographic and climatic characteristics of California have cultivated the diversity we see today. And the characteristics that make California great for wild organisms have been great for humans as well. California is a major grower and supplier of the nation's fresh fruit and vegetables, employing over 1 million people in the agricultural business. It's also famous for wine grapes, wine production, nuts, and milk.

Birdwatching Stone LakesThe climate of California, however, is changing in ways that may not be compatible with the way of life Californians have come to appreciate. The average annual temperature for the state is increasing and winter and spring temperatures in particular have been warmer. Overall temperatures across the state are projected to increase 1-2.3 degrees Fahrenheit in the next few decades. That may not sound like much, but anyone in the agricultural business could tell you that even small temperature changes can have important consequences for crops. For fruit crops, increased temperatures might mean an increase in the rate fruit develops, which will likely lead to a decrease in the size of the fruit produced. Many peach and nectarine growers experienced this phenomenon in 2004. Wine grapes, always a sensitive crop, are expected to ripen 1-2 months earlier as temperatures increase. And those that tend to the state's dairy industry may have to deal with decreased milk production as temperatures rise.

Temperature increases also have consequences for California's water supply. Spring snow levels in lower and mid elevation areas of the mountains have been dropping and snow melt has begun to occur 1 to 4 weeks earlier. These changes in snow melt will force those who depend on it to shift their activities accordingly, including growing times and harvesting times, changes which will likely be felt across the nation.

Rising global temperatures are influencing the oceans as well. Melting glaciers in the Arctic and a process called ocean thermal expansion are combining to lead to increasing sea levels along the California coast. Sea levels have risen 7 inches in San Francisco Bay in the last century and are expected to continue rising. Flooding, beach erosion, higher tides, and more severe winter storms are anticipated. For cities like Santa Cruz, which are only 20 feet above sea level, rising sea levels are an important phenomenon to consider.

What does this mean for Stone Lakes NWR?

Waterfowl at Stone LakesThe plants and animals of Stone Lakes NWR and other wild areas will not be immune to changing temperatures and water supply patterns. Already, flowers have been shown to be blooming 1 to 2 weeks earlier in parts of California. The risk of wildfire is likely to increase and could be as much as 55% more frequent by the end of the century. In northern California, warming temperatures may even lead to a shift from Doug fir and White fir dominated forests to forests dominated by Madrone and oaks. Shrubland and woodland areas inland to California may convert to grassland as wildfire frequencies increase. Some alpine and subalpine ecosystems are at risk of disappearing altogether. All of these changes and the many more that haven't been considered or projected yet, will create challenges for land managers across California, including those at Stone Lakes NWR. You can help managers at Stone Lakes track changes to plant communities by monitoring one or more of the plant species they've selected as part of BudBurst at the Refuges. The information you provide through Project BudBurst will help land managers understand how changing climates are affecting the plants they manage.


Photo: Youth birdwatching (middle) and Waterfowl at Stone Lakes NWR (bottom), Courtesy of the USFWS

Our Changing Climate: Assessing the Risks to California. A Summary Report from the California Climate Change Center. July 2006. Accessed Nov 2011.

Climatograph data from The Weather Channel website. Accessed Dec 2011.