California’s Drought: Water at the Interface of Science and Policy-Making

Drought is quickly depleting water reserves throughout California. How is the scientific community helping? Photo from CSIRO.

As scientists, we are all generally convinced of the importance of our own research, even if we don’t perceive its direct impact on society at large. It is equally easy for us to get lost in our own work and fail to notice the broader impact that science in general does in fact have on society. Science is routinely at the heart of fundamental social, economic, and political issues. When utilized properly, it can play a crucial role informing the decision-making process of policy-makers whose choices have the power to affect many lives. In this and future blog posts, I aim to delve beyond the news headlines and explore how science is used (or, at times, not used) to inform the political process.

The ability of science to inform policy is demonstrated in the recent events surrounding California, which is now in the fourth consecutive year of an historic drought. In January, California Governor Jerry Brown formally declared a state of emergency and on April 1 issued an executive order mandating a 25% statewide reduction in water usage, an unprecedented action in California. Water in California, which is largely supplied from melted mountain snowpack retained in artificial reservoirs, is indeed disappearing: According to the California Department of Water Resources, snowpack in the Sierra Nevada stands at 14% of the historic average, and the state’s two largest reservoirs are carrying only 40% of their capacity. The shortfall in water supply has led some to forecast dire consequences: Jay Famiglietti, a senior water scientist at NASA, predicted that California’s water reservoirs may be depleted within the next year. Alarming news stories have followed (“NASA: California Has One Year of Water Left”).

Whether such eye-catching headlines are accurate or hyperbolic, in the short term the water shortage is already beginning to have significant consequences for residential life and, critically, commercial agriculture. California is a major national and global supplier of agricultural products, earning its colloquial moniker as the “breadbasket of the world.” Indeed, California constitutes the ninth largest global economy and, within the United States, supplies a third of all vegetables and two-thirds of all fruits and nuts. The drought thus threatens to impact the price and availability of many food products nationwide. Within California, lost power from hydroelectric dams has led to energy price hikes, increased wildfire frequency, and mandatory restrictions in water usage have translated into reduced hours for lawn watering and even limitations on the size of lawns for new properties.

Given the consequences of the California drought both locally and globally, an important question for policy-makers is: How did California get this dry? Can science aid policy-makers in their decision-making to address the current drought and prevent such conditions in the future? To arrive at appropriate policy measures, an understanding of the causes of the drought is essential.

California: casualty of climate change?

An explanation that has received much attention, both in the public and from prominent political figures, is the possible exacerbation of anomalous weather events resulting from the increase in global temperatures over the past century. In a recent interview, Sen. Barbara Boxer (D-California) noted that, “as far back as 1995, climate scientists have predicted that increasing global temperatures would lead to more severe droughts in some regions of the world. We know that climate change is linked to the type of intense, record-breaking droughts that we are experiencing in California. The bottom line is that the impacts of climate change are real and happening all around us.” The White House has echoed this sentiment: “[w]e have to be clear. A changing climate means that weather-related disasters like droughts, wildfires, storms, floods, are potentially going to be costlier and they’re going to be harsher.”

So, how unusual is the current drought? Cyclic droughts have been occurring in North America throughout the past 10,000 years. Within the modern era, a nearly decade-long drought— the 1930’s Dust Bowl— blanketed large swaths of the American Midwest and devastated regions that were already heavily impacted by the Great Depression. In California, prolonged periods of drought are thought to have occurred long before any significant anthropogenic effects on the climate were possible. A study published in Nature in the mid-1990s, using radiocarbon dating of tree stumps, identified a period of medieval climatic anomaly (ca. A.D. 800-1350) marked by intervals of long and severe droughts in the California region. A survey of subsequent work in the field refined the emergence of extreme drought to two periods, A.D. 950-1150 and A.D. 1250-1350, and chronicles the appearance of quite negative consequences for human development in medieval California during these droughts, which engendered rapid cultural change, resettlement, disruption of trade, health problems, and escalations in violence.

While this natural history of drought may predispose some to skepticism as to whether climate change has played any role in the current drought, there is evidence indicating that drought-inducing conditions in recent years have accelerated beyond the natural expected variability. A study in PNAS found that while the appearance of low-precipitation years in California has remained stable over the past century, an increasing frequency of anomalous high-temperature years has led to a greater co-occurrence of dry and hot conditions in the last two decades (91% co-occurrence) as compared to the preceding century (42% co-occurrence). The simultaneous appearance of both conditions is a strong indicator of oncoming drought, so while drought is indeed a natural phenomenon, the increased global temperatures over the last few decades may nevertheless have played an important role in the current crisis. Climate change may thus serve as an increasingly dominant factor in drought conditions throughout the 21^st century if increased warming trends continue.

The Delta Smelt: a miniscule fish caught in a sizable controversy. Photo by Peter Johnsen, U.S. Fish and Wildlife Service

California’s smelting controversy

While the disappearance of water reserves from California represents a major contributing factor to the drought, of equal importance is the delivery of existing water to areas of the state where it is most needed. The Central Valley, which represents the agricultural center of California, is located in the naturally dry interior of the state. Ironically, it therefore requires large-scale irrigation from the Sacramento-San Joaquin Delta to maintain its rich crop growth. This has led to a controversy over irrigation, which remains hotly contested within California but has received somewhat less attention in national headlines, involving a tiny, unassuming fish: the Delta Smelt. The smelt (hypomesus transpacificus) is endemic to the saltwater-freshwater mixing zone within the delta and has a relatively short lifecycle (one year) and low fecundity, rendering it particularly sensitive to changing environmental conditions in its native habitat. The population of the smelt has been declining since the 1970s, and in recent years has reached sufficiently low levels to warrant entry onto the federal (2008) and California (2010) endangered species lists. Speculation has arisen that the extinction of the smelt is imminent. While the smelt has no commercial value and thus has minimal impact on California’s economy, it is considered by conservationists to serve as an indicator species, with its decline signaling a broader loss of biodiversity in the delta and other ecological problems that may eventually have greater human impacts.

In response to the smelt decline there has been a major effort to curtail irrigation out of the delta, following an influential biological opinion issued by the California Fish and Wildlife Service (FWS) in 2008 that argued the irrigation systems operating there are the major cause of smelt endangerment. Irrigation can lead to entrainment, whereby the smelt are diverted along artificial irrigation paths to non-native locations and die when irrigation systems are shut down in cooler months. The FWS opinion carried a great deal of weight among policy-makers and triggered a series of actions aimed at reducing smelt entrainment by limiting irrigation to the Central Valley and other regions. Currently, irrigation provides 4.7 million acre-feet of water annually from the delta, while restrictions require an additional 700,000 acre-feet to be diverted and allowed to return to the Pacific Ocean. This amount could theoretically provide water to 1.4 million households each year.

Opposition to irrigation restrictions

Recent estimates indicate that over 500,000 acres of farmland will be fallowed from the current drought, with $2.7 billion in lost revenue and roughly 20,000 lost jobs. The San Joaquin region of the Central Valley has been particularly hard-hit—as of June, unemployment there was nearly double the 5.5% national average. Given such conditions in California’s major agricultural regions, it is not surprising that efforts to restrict irrigation have met political pushback. This opposition has largely been spearheaded by U.S. Rep. Devin Nunes (R-California), whose district includes the San Joaquin Valley. Nunes has argued against “regulatory-mandated drought,” reflecting a belief held by Nunes and others that the current California drought conditions have been created, or at least exacerbated, by the irrigation restrictions. Nunes subsequently authored or co-sponsored three bills in the Republican-controlled U.S. House of Representatives—once in 2011 and twice in 2014—which aimed to curtail pumping restrictions from the delta. However, all three bills failed to gain support in the then-Democrat-controlled Senate.

Concurrent with these political battles, an ongoing legal contest over the smelt, initiated on behalf of Central Valley farmers seeking to overturn the irrigation restrictions, has moved its way through the state and federal appellate courts. This contest appears to have reached a temporary conclusion as the Supreme Court this year declined to hear arguments over an earlier appellate decision, effectively leaving irrigation restrictions in place until further congressional action is taken. Notwithstanding this seeming good news for the smelt, however, its population has failed to recover despite several years of water restrictions, suggesting other factors affecting smelt survivability, such as the introduction of invasive species, may have played a greater role than entrainment in the smelt decline than was previously appreciated.

The role of science in current drought policy-making

The California water dilemma has brought to the public’s awareness a plethora of controversial topics, and it is very likely that the smelt and climate change will remain hot-button issues locked in political debate for years to come. Meanwhile, the California drought continues apace. The onset of El Niño in late fall may ameliorate some of the dry conditions for now, but the continued threat of warming trends will likely mean more frequent, and more severe, droughts over the long term. So far, there has not been any consensus legislative solution reached during the entire four years of the drought. Despite some rather negative news reports on the likelihood of compromise legislation, however, there is a possibility that this might change thanks to two bills, one passed in the House and the other introduced by Sen. Dianne Feinstein (D-California) in the Senate. Despite their partisan origins, both bills share similar language in some areas, calling for: increased irrigation under certain conditions; improved real time data collection and analysis of smelt population dynamics; greater responsiveness of species management practices to new scientific evidence; measures to improve the removal of invasive smelt predator species; and funding to expand and modernize California’s water storage infrastructure. To be sure, there are areas that are likely to become highly contentious—for example, the House bill allows for temporary suspensions of some Endangered Species Act protections, while the Senate bill is more costly to taxpayers. But these recent developments nonetheless offer hope for California.

What, then, is the final verdict for science with respect to the debate and response to California’s water woes? While the recent legislative approaches do not address some concerns in the scientific community (such as climate change), they do appear to incorporate a data-driven approach to preserving ecosystem integrity while still helping bring water to Californians, suggesting that policy-makers have indeed been responsive to the researchers working under the radar to provide empirical evidence and objective analysis to this issue. Moreover, there are already some tangible scientific accomplishments: captive breeding of smelt at the UC Davis Fish Conservation and Culture Laboratory is incorporating genetically informed mating strategies to amplify an exogenous smelt population, while maintaining its genetic diversity comparable to those in the wild. These efforts appear to be yielding some success, bringing hope that smelt extinction is preventable.

Despite the perennial and often disagreeable divisions that arise from the political process, we should refrain from concluding that science cannot fruitfully involve itself in politically tinged issues. There is reason to remain positive that science can, and often does, serve as the underpinning of good policy and can enlighten those who have the authority to enact change.