Climate Change in the Sacramento Valley: Contemplating the Future
Last updated October 6, 2018
I’ve been reading and writing about climate change for several years now. Yet, there is that moment when you realize it has pierced the sacred spaces, the places we call home. My moment occurred during the 2017 fires in Napa and Sonoma Counties, California. Here’s my story.
The future lies just over those hills …
Years ago, I dreamed I was riding across California’s golden hills in a 20-foot-tall Winnebago. The land was barren, stretching for miles beneath a deep, amethyst sky. There were no roads or signs of life, except cows, which flew through the air as the callous driver of the Winnebago hit the occasional one or two. The Winnebago was so tall and bumbling along so fast that the driver couldn't dodge them, nor did he care to try. In the southern sky, electric strands of DNA descended from gathering clouds—pulsating ribbons of neon purple, azure and black. Needless to say, it was apocalyptic.
Lately, this dream comes to mind, and I’m sure I know why. As communities experience devastating hurricanes, floods and fires, the present feels unfamiliar—the future, apocalyptic. Yet, scientists say if we continue burning fossil fuels without a viable plan to bring carbon emissions down to net zero, global temperatures could rise 4°C by the early 2060s to the 2070s. Earth—the planet we’re attached to, the one that has sustained us for millennia—would seem alien. And though it’s not too late to avoid a catastrophic temperature increase, we haven’t yet devised a feasible plan to prevent it. The future could be closer than we think: perhaps, to the west, just over those hills.
I moved back to Davis, California—a small city located in the Sacramento Valley, 11 miles west of Sacramento—in August of 2017 at the age of 57, having lived in Southern California and, more recently, the Bay Area since 2002. I longed for deciduous trees, a small-town feel and that sense of belonging that comes from taking root in a place for a very long time, so I plotted my return. And although Davis is a bustling university town with London-style-double-decker buses, parents ferrying kids here and there and hordes of bicycles, it also has a quaint downtown, trees that reach across quiet streets and open space.
Part of that space includes the Yolo Bypass—a 40-mile-long floodplain between Davis and Sacramento—which diverts water from the Sacramento River during flood season. Though throughout the year, it also provides a rich habitat for migratory birds and other wildlife while supporting agricultural crops, such as rice. Indeed, during late spring and summer, the rice fields stretch to the steps of Sacramento!
Napa and Sonoma county fires
I expected the area to be mostly unchanged. But in October, when fires erupted in California’s Wine Country, I sensed things would be different. Davis, in fact, lies 35 miles east, as the crow flies, from Napa and Sonoma Counties, where the October 2017, Northern California wildfires destroyed lives and property. Soon after the fires started, I watched as reddish-brown plumes of smoke billowed from behind the Vaca Mountains, which form a natural boundary between Davis and the Napa Region. And from what I had read in the news, I could only imagine the horror on the other side.
And though the smoke mostly stayed closer to the fires and in the Bay Area, one night while we slept, it crept in. Winds shifted so that ash fell like snow. The air was so thick with smoke that kids had to stay home from school because the particulate matter triggered their asthma. Still, compared to the death and destruction in Napa and Sonoma Counties, Davis was lucky. Our biggest threat from surrounding fires is poor air quality from smoke that gets trapped in the Sacramento Valley. But nothing like this happened when I lived here before. Heavy winter rains followed by a profusion of spring flora and hot, dry, windy conditions lingering further into fall set the stage for these fires, factors expected to occur more often as Earth warms.
Climate change in the Sacramento Valley—what scientists predict
Atmospheric rivers, droughts and less snow
Yet, even if the world stopped emitting greenhouse gases tomorrow, global temperatures would continue to rise another 40 years or so because the oceans warm more slowly than the atmosphere and eventually release that heat back into the air. As a result, smoke from local fires is just one of many challenges the Sacramento-Davis Area will likely face this century. Climate scientists forecast that severe floods, similar to the ones in Houston during Hurricane Harvey, will occur more often because of an upswing in atmospheric rivers, large storms with powerful winds and heavy rains that swamp California in winter. Some of those could rival the Great Flood of 1862 and cause extensive flooding. They could also compromise delta levees. And the fact that additional moisture is predicted to fall as rain instead of snow will compound risks while also reducing Northern California’s watershed, which relies on snowpack. On the other hand, scientists project an increase in extreme dry winters, too.
Though depending on the extent of sea-level rise, parts of the Sacramento Valley could also become a year-round inland sea as the San Francisco Bay encroaches on the Sacramento-San Joaquin Delta. A map at Climate Central shows the Bay extending to the outskirts of Sacramento by 2100, even with sharp cuts in carbon emissions. And if global temperatures increase by 4°C, the waters would reach neighborhoods in Davis, too, although scientists can’t yet predict when that would occur. Likewise, the town of Napa would succumb to water from the Bay because of its location on the Napa River, which empties into the San Pablo Bay, part of the San Francisco Bay Watershed. The resulting saltwater intrusion could negatively affect drinking water and water used for crops.
Heat, dust and vector-borne diseases
But the Davis-Sacramento Region will also get much hotter. Annual average temperatures in this area are expected to rise 3.8°F–6.4°F (2.11°C– 3.56°C) by 2099 with the number of days exceeding 100°F (37.8°C) occurring at least four times as often, depending on emissions. Such extremes can lead to more heat-related illnesses and poor air quality by increasing the formation of ozone, which affects the elderly and people with asthma and respiratory diseases. Also, warmer temperatures result in drier soils, which can become airborne from activities that disturb the dirt, such as construction, farming and even large-scale solar projects. In fact, the number of dust storms in California have recently climbed and are most likely the primary driver behind higher rates of valley fever—a dust-borne fungus that, when inhaled, can be fatal to humans. And local health departments worry, too, that rising temperatures will increase cases of vector-borne diseases, such as Lyme, human hantavirus and West Nile virus.
Flora and crops
There will be more of some things and less of others: perhaps, more pests, melons, sweet potatoes, lettuce, broccoli, tomatoes, rice and alfalfa; yet, fewer fruit trees, walnuts and less winter wheat and, possibly, even tule fog, which blankets the valley in winter and boosts the dormancy period for nut and fruit trees. Over a span of 32 winters between 1981 to 2014, tule fog has decreased on average 46 percent, most likely due to climate-driven warmer temperatures and wide swings from very wet winters to dry ones. Blue and valley oaks are likely to suffer from heat and drought, resulting in range shifts farther north and to higher elevations, if possible. And though certainly not a food security risk, higher temperatures shorten autumn’s brilliant leaf color and, more importantly, confuse plants’ growth cycles.
Imagining the future …
As fall settles in the Sacramento Valley, I drive across town on the freshly paved road that leads to a local strip mall, no less, and peek in my rearview mirror in time to catch the sun slipping behind the Vaca’s amaranthine peaks. They are luminous, silhouetted against November’s rose-streaked sky—smoke and fire, spent. Straight ahead, the Yolo Bypass spreads east across the horizon to the city of Sacramento, which rises out of a field of wild rice straw. Beyond that, lie the Sierra.
My thoughts shift centuries ahead to a plausible future, and I imagine I’m crossing an inland sea. Both the Sierra, to the east, and the Vaca Range, to the west, are smoldering from recent fires. The town of Napa, which sits 20 feet above sea level, is only accessible by small watercraft, and crazed investors donning scuba gear are salvaging centuries-old relics from sunken wineries. Davis, on the other hand, is 52 feet in elevation and hasn’t yet succumbed to the sea. But water is lapping at the edges of town. By 2500, it could be swallowed up, too.
I drift back to the present to soak up the waning afternoon and sleepy oaks that dot fallow fields—one of many pastoral scenes that make Davis so special. And though it’s doubtful I’ll have to escape fires and floods in a 20-foot-tall Winnebago while dodging cows and electric DNA, as temperatures rise and the risks from natural disasters increase, will I want to stay? And if not, where on Earth would I go?