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Climate change-induced shifts in snow storage and snowmelt patterns pose risks for adverse impacts to people, the environment, and irrigated agriculture. Existing research primarily focuses on evaluating these risks to irrigated agriculture at large scales, overlooking the role of local context in shaping risk dynamics. Consequently, many “at-risk” areas lack insight into how adaptation strategies for managing risk through water supply augmentation or water conservation vary across contexts and over time. To address this gap, we develop a comprehensive index for evaluating irrigated agriculture's risk and adaptation potential to changes in snow at local scales and apply it throughout the western US. Results confirm trends toward escalating risk for changes in snow storage and snowmelt patterns over the century. However, substantial heterogeneity in the extent and drivers of risk exists due to variability in localized interactions between declines in water supply (approximately −9% ± 13% by 2100) and increased agricultural demand (approximately 7% ± 5% by 2100). Despite an existing focus on supply augmentation as a critical adaptation strategy to reduce risk, we show its effectiveness diminishes for many areas over time, declining to an average of −54% of historical augmentation potential by 2100. Conserving water through historical changes in crop acreage and type emerges as a more stable adaptation measure, reducing demand by 7%–8% regardless of time. While particularly relevant for higher elevation, less intensive agricultural settings in snowmelt-dependent regions, findings underscore the need for strategies that support local-scale, context-appropriate adaptation to effectively manage escalating risk as snow changes.

Spillover impacts pose challenges for the management of protected areas (PAs). The issue of external threats encroaching on PAs has long been recognized, but a corollary—that PA conservation can increase costs borne by neighboring governments or landowners—is less well appreciated. In some contexts, basic principles of fairness and cooperation suggest that PA users should help pay these costs. Several countries have developed mechanisms for distributing the costs of spillover impacts to PA users, but not the United States. Here, we investigate whether and how US park visitors could help address one type of spillover, the need for wildlife conservation efforts beyond park boundaries, using a case study of the Greater Yellowstone Ecosystem (GYE). We examine a “conservation fee” recently proposed in the Wyoming legislature, along with tax-based alternatives. After exploring some costs of wildlife conservation in GYE, we estimate that a fee of up to $10 per vehicle could generate up to $13 million annually, and tax-based approaches considerably more. We consider legal, political, and governance challenges, and ways to mitigate them. The GYE could serve as a demonstration site for visitor funding of cooperative, large-landscape conservation, for potential future expansion in the US and beyond.

Abstract: The American West confronts the challenge of fulfilling indigenous claims to water within the context of increasingly scarce and variable water supplies. 170 of 226 American Indian reservations have unresolved water claims that potentially exceed the region’s hydrological capacity, generating uncertainty for tribes and off-reservation water users. To help resolve key uncertainties about dispute origins and outcomes, we construct a complete and novel dataset on Indian water settlements and reservation characteristics which we then analyze using a bargaining framework from economics. We find that rapid off-reservation population growth, water scarcity, and large anticipated water entitlements catalyze disputes. When more users are involved in the negotiations, transaction costs delay settlement, increasing water insecurity. We use our findings to predict allocations for 25 ongoing water right negotiations. These estimates help bound the uncertainty facing water managers throughout the American West.

Rationale: Interrupting tuberculosis (TB) transmission requires an improved understanding of how and when the causative organism, Mycobacterium tuberculosis (Mtb), is aerosolized. Although cough is commonly assumed to be the dominant source of Mtb aerosols, recent evidence of cough-independent Mtb release implies the contribution of alternative mechanisms. Objectives: To compare the aerosolization of Mtb bacilli and total particulate matter from patients with TB during three separate respiratory maneuvers: tidal breathing (TiBr), FVC, and cough. Methods: Bioaerosol sampling and Mtb enumeration by live-cell, fluorescence microscopy were combined with real-time measurement of CO2 concentration and total particle counts from 38 patients with GeneXpert-positive TB before treatment initiation. Measurements and Main Results: For all maneuvers, the proportions of particles detected across five size categories were similar, with most particles falling between 0.5-5 μm. Although total particle counts were 4.8-fold greater in cough samples than either TiBr or FVC, all three maneuvers returned similar rates of positivity for Mtb. No correlation was observed between total particle production and Mtb count. Instead, for total Mtb counts, the variability between individuals was greater than the variability between sampling maneuvers. Finally, when modelled using 24-hour breath and cough frequencies, our data indicate that TiBr might contribute more than 90% of the daily aerosolized Mtb among symptomatic patients with TB. Conclusions: Assuming the number of viable Mtb organisms released offers a reliable proxy of patient infectiousness, our observations imply that TiBr and interindividual variability in Mtb release might be significant contributors to TB transmission among active cases. [ABSTRACT FROM AUTHOR]

We develop a two‐stage model to study the strategic interaction between a politician (the principal) and a bureaucrat (the agent) over the level of infrastructure provision with uncertainty about possible weather shocks. The bureaucrat chooses how much effort to contribute to infrastructure maintenance and the politician offers either a lump‐sum wage (non‐corrupt) contract or proportional bribe (corrupt) contract to induce effort. The degree of uncertainty about weather shocks, the size of the fixed wage, and the level of external monitoring to detect corruption all interact to affect (a) the politician's choice of contract and (b) whether this choice improves infrastructure outcomes. Our results suggest that curbing corruption is most likely to yield improvements in infrastructure provision when climate uncertainty is low and when bureaucratic wages are relatively high. If climate uncertainty is high, increasing monitoring has an unambiguous negative effect on infrastructure provision. Previous literature has focused either on public goods provision but not corruption or on bribery in a regulatory context that lacks public goods provision. We extend both literatures by analyzing how bribes between government officials affect a principal's ability to more effectively incentivize public goods provision by her agent. [ABSTRACT FROM AUTHOR]