An article in the Summer 2017 California Magazine for the Cal Alumni Association of UC Berkeley asks how California is going to adapt to the Anthropocene.
For those who have been living under a rock for the past decade or so – an appropriate metaphor since this concerns geology – the Anthropocene, or Age of Humans – is the proposed name for the geologic era in which we are now living. It is an era in which human beings and our vast empire of machinery have become a dominant geologic force on a planetary scale, with enormous effects on the Earth’s biophysical environment (the biosphere) and climate.
Dutch atmospheric chemist and Nobel laureate Paul Crutzen first coined and popularized the term in 2000. It has since become a buzzword of sorts, for those who believe that the profound and powerful human influence over the biosphere needs to be acknowledged, for better or worse.
In the Anthropocene, Californians are likely to confront not just “hell or high water,” but rather “hell AS WELL AS high water,” in the form of more scorching temperatures, longer and more devastating droughts, more intense wildfires, more severe storms and floods like those of the winter just passed, and accelerated sea level rise.
This past winter, Californians was ravaged and savaged by perhaps a foretaste of the extreme weather that is in store for the state over the coming decades and beyond, according to scientists.
California’s poster child for the fury of last winter’s storms and flooding is the 770-foot high Oroville Dam on the Feather River in the Sierra Nevada foothills. The winter’s record-breaking rainfall had filled immense Lake Oroville almost to the very crest of the earthfill embankment dam that holds back 3.5 million acre-feet of water. To avoid a disastrous overtopping, the lake’s managers had released vast volumes of water into the dam’s main spillway. But then the thundering, pounding deluge of water destroyed the spillway’s concrete surface, dislodging and pulverizing massive slabs of concrete and gouging out a crater on the adjacent hillside.
Meanwhile, water levels in Lake Oroville continued to rise, and water poured across the dam’s emergency spillway for the first time in its nearly half-century history. Because the slope below this spillway was unlined with concrete, it eroded quickly, jeopardizing the integrity of this structure. As a precaution, some 200,000 residents downstream of the dam were evacuated during the crisis, making national news.
Fortunately, thanks to the whims of the weather gods and the dogged determination and skill of workers at the Department of Water Resources, a catastrophe on the order of a Hurricane Katrina with its staggering loss of life and property was averted…this time. How long our luck will hold in a future ever more besieged with extreme weather is anyone’s guess.
One thing we do know is that if state population growth projections come to pass, ever larger numbers of Californians will be exposed to nature’s more and more frequent wrath. Climate models generally predict more extreme, volatile weather patterns for California.
One possible engineering response to more frequent and furious droughts and floods would be larger reservoirs with greater storage capacity both for drinking water and to hold back floodwaters, but this is a controversial solution to say the least because of its environmental impacts. Politically, at least in the short term, this sort of adaptive measure is a non-starter in the Democrat-controlled state legislature.
It is unlikely that California’s aging water infrastructure of dams, reservoirs, spillways, tunnels, levees, and aqueducts is up to the challenge. Many of these structures were built half a century or more ago in pre-Anthropocene conditions. It was literally a different era.
In the Sacramento Delta, at the confluence of the Sacramento and San Joaquin rivers just upstream of San Francisco Bay, not only are levees and the electrical grid at risk of catastrophic flooding and failure from dam breaches upstream, but the delta and its levees will also be affected by sea level rise for the rest of this century and beyond. Indeed, we are likely in for a much faster rate of sea level rise in the near future.
By 2100, some estimates are that sea level could rise by as much as six feet (with much higher levels in store over the following centuries). If that happens, two-thirds of Southern California’s beaches would disappear under the waves.
Even a four-foot sea level rise would expose more than a quarter-million people in the Bay Area and Sacramento Delta to death and displacement during a 100-year flood event, according to a 2012 report to the California Energy Commission. Infrastructure worth tens of billions of dollars would also be wiped out.
Ultimately, California – like coast-hugging New York and Florida, two other states highly exposed in the Anthropocene – is going to have to “think outside the box” in adapting to the climate challenges headed our way. Some areas may simply have to be abandoned to the surging tides and waves, while in other locations, higher-value real estate and more potent political clout may argue for taller levees, dikes, and sea walls, as well as different construction methods and materials and even “floating cities”.
Adapting to the Anthropocene will be costly and controversial, but as the clever Dutch have shown in their centuries of living with water, even living below sea level, it is doable both politically and technically. Economically may be another matter.
But unlike the Dutch in their tidy little country, Californians will have to deal with both fire and rain, with both droughts and floods on a much vaster scale with a much larger population at risk. Fifty years from now, the state may be a very different place than it is at present, and a completely different world than it was just 50 years ago.