How might climate change affect SoCal?

Average Temperature Plot

Describing the climate of Ventura County is not easy. With an area of almost 18,000 square miles (about the same as the entire state of Connecticut) there's plenty of room for different climates. Although botanist David Magney has described 51 different biological regions within the county, it's easier to think of Ventura County as being made up of five general regions: the Cuyama badlands, the Western Traverse Ranges, the Santa Monica & Santa Susana Mountains, the Channel Islands, and the Coastal Plain & Valleys. Each of these regions has a different climate.

Near the coast, the climate is sometimes described as Mediterranean, with temperatures that don't vary much from season to season. In Ventura and Oxnard, the warmest month is usually August (with an average high temperature of 74°F), while the coolest month is January (66°F). These cities receive about 16" of rain each year, mostly between November and March. The rest of the year is normally very dry.

However, just 15 miles inland, the climate is quite different. The city of Ojai, in the Western Transverse Ranges, is usually 8 degrees warmer in summer and 6 degrees cooler during the winter. It receives about 6 more inches of rain each year, too. Because various plant species need different temperatures and rainfall, they can only grow where the climate conditions are ideal.

California Condor

Most climate scientists predict that California's climate will grow warmer this century. Current predictions range from an increase of 1-2.3°F during the next 30 years to as much as 3-10°F by 2100. One or two degrees might not sound like a big change, even that much change would have a big impact on Ventura County!.

In addition to increasing the number of wildfires, climate change will shift the suitable range for many plants further to the north and to higher elevations. For example, scientists have discovered that temperatures in the Sierra Nevada Mountains have increased by about 5°F between 1934 and 1996, causing the ponderosa pine forest to move an average of 4.4 miles to the east and upward by more than 630 feet.

Climate change will increase stress on the state's ecosystems and biological diversity. For example, in northern California, warmer temperatures are expected to shift the dominant forest species from Douglas and White Fir to madrone and oaks. In other inland areas, the increasing number of wildfires is expected change shrub and woodland areas into grasslands. Alpine and subalpine ecosystems are among the most threatened; the plants that live there won't be able to move "up slope" and as many as 60 to 80 percent of them could die off by the end of the century as a result of increasing temperatures.


Photo: California condors at Hopper Mountain National Wildlife Refuge; Courtesy of USFWS

Dave Magney's Flora of Ventura County.

California Climate Change Portal.

NOAA Climate Change Services.