Droughts in the Anthropocene

California – Mitigating the socioeconomic impacts of drought

With a population of 39 million, California has one of the largest economies in the world. Population growth and urban water demand combined with increasing droughts and agricultural water use provide a significant challenge for water governance. California is often referred to as the ‘salad bowl’ of the United States, producing 400 agricultural commodities and two-thirds of the nation’s fruits and nuts [1]. Agriculture is the key source of employment in rural areas. Agricultural workers predominantly come from low socioeconomic backgrounds and their economic stability and health are particularly vulnerable to climate change and events such as droughts [2]. Droughts have long been a part of California’s climate, but the 2011–2015 drought broke records and was estimated to be the worst in 1,200 years [3], its severity increased as a result of climate change [4]. Starting in 2011, the conditions within California deteriorated, escalating from a ‘drought’ to an ‘extreme drought’ into the ‘exceptional drought’ category [5]. The severe lack of water undermined the social, economic and environmental systems that had developed around its availability in California. The increased pumping of groundwater mitigated some of the drought impact, yet it resulted in groundwater deficits and land subsidence and was not a sustainable solution. Agriculture, being widely reliant on irrigation, was hit hard by water scarcity and considerable increases in pumped water costs, resulting in a 45 per cent increase in unutilized farmland [6]. High costs combined with decreased crop yields resulted in 21,000 jobs being lost and economic losses of US$2.74 billion, not including losses in ecosystem services [5]. The impacts of the drought on communities were not uniform. Among low-income tribal groups

and minorities, the burden of the drought was far greater due to sensitivities to increased food and water prices. In the rural communities most acutely affected, the drought impacted human health and water and food security [7], while in urban areas, the impacts were primarily limited to enforced water restrictions. The hot, dry conditions of the drought contributed to the severity of the Californian wildfires [8], including the Valley and Butte fires of 2015 that rank among the most devastating in the state’s history and that each resulted in a declaration of a state of emergency. The two fires resulted in six fatalities and the loss or damage of an estimated 2,876 homes and businesses [9]. The drought revealed significant vulnerabilities within the current water management regime, threatening the agricultural sector, ecosystems and urban water resources. In 2014, the California Water Action Plan was released in response to the extreme drought. The plan acknowledged that California’s water management practices were unable to meet both human and ecological water needs [10]. The action plan was holistic, incorporating governance at the federal, state, local and tribal levels and considering industry and NGOs’ involvement. Importantly, it led to an improved planning approach that incorporates the uncertain effects of climate change and other major risks. The Decision Scaling Vulnerability Assessment tool helps decision makers deal with uncertainties and understand vulnerabilities within the water management system, quantifying status quo management costs and risks compared to different adaptation scenarios. The tool is particularly useful for addressing uncertainties in climate change projections as it evaluates changes

in temperature and precipitation over different climate scenarios and their potential impacts at different spatial scales. Importantly, the bottom-up approach improves the identification of vulnerabilities at a local scale, which are then aggregated into regional and state-wide scales. The monitoring system provides information on a range of water management aspects aligned with pivotal decision-making points throughout the year, allowing decision makers to mitigate and adapt to potential water scarcities [11]. The incorporation of urban, irrigation and environmental water demands, supports a balance between these competing needs. The monitoring of river flow metrics allows for environmental water requirements to be better understood in different climatic conditions, supporting water allocation adjustments to counter saltwater intrusion, which impacts both farms and ecosystems. Recent technological innovations, such as the Gravity Recovery and Climate Experiment (GRACE) satellite system, have provided new information on groundwater trends and availability, which can be integrated into future models. Furthermore, the 2014 California Water Action Plan addresses the increasing demands on water resources through raising awareness of water conservation as a ‘way of life’. This has been implemented in public campaigns such as Save our Water, aimed at changing behaviours around water uses. Through this holistic and comprehensive approach to management, California is building knowledge and implementing actions that can support sustainable solutions to water management in the Anthropocene.

EUROPE AND NORTH AMERICA

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