The importance of diversification and its variation across specific industries points to the conditions under which yield insurance may be of interest and where it is less important to a farm’s annual revenue and thus less appealing as a risk management tool. The covariance between price and individual farm yield is another crucial piece of information in assessing farm revenue risk related to either price or yield variability. USDA’s Risk Management Agency has been developing whole-farm revenue insurance products.Our analysis shows that no one risk management tool fits all growers. Some risk-related patterns may be ob served broadly in certain segments of farms. However, those patterns change when smaller subcategories of crop producers are analyzed because risks and the way growers manage them depend on many complex factors. One implication is that insurance products that are designed and targeted for individual crops may miss the whole farm interactions. In reality, an insurance product for a specific crop would work differently for different growers depending on their characteristics outside the specific crop. It is also vital to better understand the risk management tools that growers currently use when designing public policy to help farmers manage risk. In many cases, public policy for risk management can be effectively designed to accommodate and complement rather than substitute for or conflict with the risk tools that growers already value and use. Overall,rolling benches the results of this survey suggest that one must proceed with caution when attempting to develop government-sponsored risk management programs.

Pro grams may fail to meet objectives and may have serious unintended consequences unless the full set of opportunities and constraints facing farmers is well understood and the differences across farms are incorporated in the program design. This study shows the complexity of risk related costs and revenues associated with the fruit, nut, vegetable, and ornamental horticulture industries in California. The data summarized in this report also can be useful for further research. These data, together with information on grower costs and returns, can help analysts better understand variations among horticultural crop industries in California and elsewhere. Researchers are also pursuing more detailed analyses of the data. For example, these data are ideal for measuring patterns of diversification and, in some cases, vertical integrations and for examining the multivariate patterns of these with alternative measures of farm size. Assessing other, more detailed relationships among the variables is also on the research agenda. This report does not attempt to disentangle the various causal relationships among the data. Such research is on the horizon. Finally, this survey provides a one-time cross-section on many important variables. Periodic re-surveys would allow researchers to track the path of adjustment and allow assessment of industry dynamics with rich, repeated cross-sectional information.The last two decades have seen a worldwide liberalization of cannabis production and consumption . As of January 2020, recreational use of cannabis is legal in Uruguay, Canada and 12 US states, and medical use is partially or fully legal in 36 countries . As legal markets for cannabis develop, policy makers are tasked to regulate its production, distribution and consumption in new ways. With rising liberalization, researchers have taken a growing interest in the potential environmental impacts of cannabis – a dynamic partly fueled by growing public concerns and news coverage of the topic, which increased by over 500% from 1992 to 2019 . If implemented successfully, legalization could give regulators a chance to anticipate and regulate the environmental outcomes of the cannabis industry as it expands .

Some current regulatory schemes already reflect this priority through the inclusion of specific language meant to reduce environmental impacts which can arise from land, water and energy use, application of chemicals, or other pathways . There are four primary classes of cannabis production which may impact the environment through different pathways and at different magnitudes . These production systems are not always clearly distinct in practice: for instance, in a single farm, mother plants may be kept indoors while cloning occurs in mixed-light and full crops are produced outdoors. Aside from trespass systems , which we describe separately due to the specific practices associated with them, the cannabis production systems we describe can exist legally or illegally. There are distinct trade-offs between production systems. Indoor systems are associated with few concerns about wildlife habitat destruction, water diversion or pollution, but require high external inputs such as energy and fertilizers. Conversely, outdoor farms may require fewer resource inputs, but poor management or siting could disrupt surrounding ecosystems. Well managed systems can minimize environmental impacts. We note that trespass grows are generally only associated with negative environmental impacts. Researchers investigating interactions between cannabis and the environment have faced historic hurdles – often due to cannabis’ legal status – which include societal stigma, funding restrictions, safety concerns and difficult access related to remote cultivation sites, as well as regulatory obstacles such as complex licensing requirements and restrictions on cultivar testing . Despite such limitations, a new science around cannabis and the environment is starting to emerge. Our objective here is to review existing literature documenting environmental impacts of cannabis, to identify significant research findings and knowledge gaps and to suggest policy recommendations. As shown in Fig. 3, before 2012 only a handful of studies suggested links between cannabis and environmental degradation . Recent empirical studies, however, have started to quantify specific environmental impacts of cannabis cultivation and consumption.

While limited in size and scope, this first generation of studies provides an opportunity to identify and summarize both what is known about cannabis and the environment, and what knowledge gaps persist. This review highlights the emerging science around cannabis and the environment. We hope it can serve as a catalyst to encourage more research in this area and as a resource to provide science-based guidance for policy-makers. We evaluated peer-reviewed and non-peer-reviewed sources that quantified the effects of cannabis cultivation or consumption on the environment. We excluded studies and reports that: addressed other impacts of cannabis such as on human health; focused on other plants or other illicit drugs; or commented on environmental impacts without providing data. Based on published commentaries on cannabis and the environment , we identified a list of terms to search the Web of Science for relevant studies in June-July 2019 . We screened titles and abstracts of resulting studies according to the three eligibility criteria noted above,ebb and flow bench yielding a total of 14 peer-reviewed articles for which we reviewed the full text. We incorporated nine additional studies referenced in these studies in our final review . We also searched for non-peer-reviewed literature on Google in July-August 2019 and included documents found in the first five pages of results. Our final review includes two non-peer-reviewed reports and a book series . We found six peer-reviewed studies that investigated the water footprint of cannabis cultivation , all of which focus on northern California. Bauer, et al. used satellite imagery to estimate the number of cannabis plants in northern California and used this to predict that watershed-scale water consumption may exceed local stream flow during the growing season. These results were based on assumptions that: on average, a cannabis plant consumes 22.7 liters of water per day throughout the growing season; this water is predominantly accessed through surface-water diversions; and water application equals water extraction. The authors suggested that during dry years, cannabis farming could completely dewater some streams. Butsic and Brenner applied a similar methodology to estimate annual water use for cannabis irrigation at 11,000 m3 – equivalent to 0.001% of annual agricultural water use – in Humboldt County, California. These findings highlight the potential impacts of cannabis on water resources, but their accuracy is limited by a lack of actual water use data. Three additional studies in California examined cultivator-reported water use for cannabis at the farm scale. High variability in water use and extraction practices was documented – likely driven by variation in seasonal growing patterns, farm size or cultivation methods. Wilson, et al. and Dillis, et al. both confirmed that water use rates among California cannabis farmers approximated the 6 gallon per-plant figure reported by Bauer, et al. . However, this was only the case during peak growing season and respondents reported lower water use rates throughout the rest of the year. Wilson, et al. also documented monthly water use on average-sized farms in California and found that while water application to cannabis plants exceeded this rate during cannabis’ growing season, water extraction from rainwater, surface and sub-surface sources remained far below it for most of the year. In separate assessments of farm scale water extraction practices, Wilson, et al. and Dillis, et al. showed that sub-surface wells, rather than surface-water diversions, may be the primary source of water for many northern Californian growers.

Sub-surface water extraction may threaten connected watersheds if annual extraction exceeds recharge rates, as sub-surface water reserves tend to recover more slowly from overuse than surface sources. We found one peer-reviewed study and one gray literature report focused on cannabis and energy use. Mills estimated that indoor US cannabis production uses 20 TWh of electricity annually, leading to the annual emission of 15,000,000 tons of CO2. This value is equivalent to the energy consumption of the entire US agricultural sector , or to 1% of US total national electricity use. Mills’ calculations were based on national cannabis cultivation estimates and assumed “typical” energy use for indoor production and relevant transportation processes. A more recent report combined estimated US cannabis demand and cultivation area with self-reported data from cultivators to provide a detailed assessment of current cannabis energy use. Combined illicit and legal cultivation were estimated to consume 4.1 MWh annually, equivalent to 472,000 tons of associated CO2 emissions. These estimates did not account for off-grid energy use, transportation, fertilization or irrigation, but were significantly lower than the numbers reported by Mills . We note that Mills’ findings may not accurately represented energy use by the US cannabis sector today, as cultivation practices have likely become more efficient in recent years. Studies quantifying land-use impacts of cannabis remain scarce despite reports of significant cannabis cultivation activity in North and Sub-Saharan Africa, the Americas and Asia . We found five empirical studies from the US which assessed cannabis and land-use dynamics. Satellite data for California showed a high concentration of cultivation sites in remote, ecologically sensitive areas . In Humboldt County, cannabis’ impact on land cover change from 2000 to 2013 was relatively limited, contributing 1.1% of forest canopy area loss compared to 53.3% from timber harvest . However, remote cultivation sites were linked to landscape perforation as they created gaps in forest patches, reducing forest core areas and increasing open edges. This could contribute to landscape-wide forest fragmentation and resulting wildlife habitat degradation if current expansion rates persist . The spatial distribution of cannabis farms, in addition to total land-use footprint, may thus be significant determinant of potential environmental impacts. These reported spatial dynamics suggest that the factors driving the location of both legal and illegal cannabis cultivation are distinct from those of other crops. Cannabis prices and law enforcement related risks emerged as important factors determining siting decisions in California, Oregon and Washington’s illicit markets . Butsic, et al. documented strong network effects amongst growers in Humboldt County, which led to clustering of cultivation sites and appeared to be more important than biophysical factors such as soil quality or terrain. Klassen and Anthony identified state enforcement capacities and poverty and unemployment rates as potential factors leading to a decline in illegal farms discovered in Oregon, but not Washington, following legalization in both states. Although pesticides used in cannabis production are likely to impact the environment, to our knowledge no quantitative studies have documented these impacts on private land or legal cannabis production systems. We found five peer-reviewed studies which focused on impacts of anticoagulant rodenticides on local wildlife species in trespass grows. ARs are presumably used to control rodent populations; they are frequently encountered on trespass production sites in California and can bio-accumulate in the food chain . In northern and central California, field-studies documented contamination by highly toxic ARs in an endangered predator, the Pacific fisher , using a combination of field-data collection, lab data analysis and spatial correlation .