The highest mountains in the West run north-to-south through the Mediterranean latitudes and just 150 miles from the Pacific Ocean—a remarkable stroke of geologic luck that has made California one of the richest ecological and agricultural regions on the continent.
These mountains accumulate deep snow in the winter, which in turn feeds cold rivers that flow through the hot, dry months. But the unique conditions that California’s native fish, its farms and its cities depend on are acutely threatened by climate change. In 2015, virtually no snow fell in the Sierra Nevada.
Droughts occur naturally, but research indicates the current drought in the American West has been made worse by climate change—and that future droughts will be exacerbated by the warming planet. A 2015 paper published in the journal Geophysical Research Letters calculated that climate change has made California’s current drought as much as 27 percent worse than it would otherwise have been. In 2015, Stanford researchers, led by associate professor of earth sciences Noah Diffenbaugh, predicted that extremely hot years in California will increasingly overlap with dry spells in the future. Greenhouse gases, the scientists reported, are pushing this trend. Diffenbaugh explained to The New York Times that, even if precipitation remains ample, warmer winters in the future will mean less water stored away as snow—historically the most important reservoir in the state.
As water supplies shrink, the human population is booming. By 2050, the agencies that manage and distribute California’s water will be answering to the needs of roughly 50-60 million people as well as the state’s enormous agriculture industry. Current squabbles over California’s water will escalate into blistering fights, and native salmon—once the main protein source for the West Coast’s indigenous people—will probably vanish in the fray as the Sacramento and San Joaquin river system is tapped to the max for human needs. Other native fishes, too, like green sturgeon, will almost certainly dwindle or disappear.
The atmospheric buildup of greenhouse gases will manifest in other ways, too. Disruption of ocean currents could reduce the upwelling of cold bottom water so critical for California’s coastal ecosystem. California’s shoreline will erode as the sea level rises, threatening coastal real estate, roads and public space. In 2009, the Pacific Institute released a report predicting that a 100-year flood combined with a 5-foot rise in sea level could cause more than $100 billion in damage, most of it in the San Francisco Bay area.
Californians are as much to blame for climate change as nearly any other comparable economy. In 2013, California generated 350 million metric tons of carbon dioxide pollution—more than every other state except Texas, which emitted more than 600 million. Most of California’s emissions came from burning petroleum, and more than half could be linked directly to transportation—mostly private vehicles. Globally, the United States’ 324 million residents generate more carbon dioxide from fossil fuels than every other nation but China. Even all the nations of the European Union emit just 60 percent as much CO2 as Americans do, in spite of outnumbering Americans by almost 200 million.
California has responded to the alarms of climate researchers with aggressive emissions goals. Assembly Bill 32, the California Global Warming Solutions Act of 2006, called for reducing greenhouse gas emissions rates to 1990 levels by 2020. More recently, the California Assembly passed Senate Bill 32, which extends some of the targets of AB32 to 2030, at which point the new law requires California to be emitting 40 percent less greenhouse gases than it was in 1990.
These goals will likely prompt shifts to renewable energy and sustainable agriculture, a carbon fee, more walking and cycling in place of driving, and adoption of clean energy. If other governments follow suit, rates of global warming could be slowed or stopped.
If business continues as usual, though, Californians will reap what we sow.