Abstract: While shale gas development can result in rapid local economic development, negative externalities associated with the process may adversely affect the prices of nearby homes. We utilize a difference-in-differences estimator with additional controls for house fixed effects and the boundary of the public water service area in Washington County, Pennsylvania to identify the capitalization of groundwater contamination risk in property values, differentiating it from other externalities, lease payments to homeowners, and local economic development. We find that proximity to wells increases property values. However, groundwater contamination concerns fully offset those gains by reducing property values up to 26 percent.

Abstract: Using the land tenure system in Ethiopia, where all land is state-owned and only farm households have usufruct rights, as a case study, we assessed the links between land owners’ tenure insecurity, associated behavioral factors, and contract length. In this paper, we analyze these links with survey data of rural households in the Amhara National Regional State of Ethiopia. The empirical strategy follows a hazard function model employed in duration data analyses and investigates the fitness of the data to the alternative exponential and Weibull functional forms. The results show that landlords’ risk aversion increases the duration of contracts, which is in line with the reverse tenancy argument that landlords’ risk preferences affect land-contract decisions. The findings of the study also indicate that tenure insecurity is a critical factor in the nature and length of contracts; hence, policies should aim to reduce landlords’ frustrations regarding future land redistribution by the state. An important implication of the results is that secure tenure systems can reduce the disincentives from tenure insecurity due to uncertainty about contract duration and thereby enhance tenants’ welfare. Longer-term and stable contracts can improve the land rental market. In addition, the impact of risk preferences points toward the importance of poverty in the functioning of the land rental market.

Abstract: This paper reviews the empirical literature on the economic impacts of natural disasters to inform both climate adaptation policy and the estimation of potential climate damages. It covers papers that estimate the short- and long-run economic impacts of weather-related extreme events as well as studies regarding the determinants of the magnitude of those damages (including fatalities). The paper also includes a discussion of risk reduction options and the use of such measures as an adaptation strategy for predicted changes in extreme events with climate change.

Abstract: This paper analyses the economic impacts of climate change on Ethiopia’s agriculture using a countrywide computable general equilibrium model. The impacts on agriculture are based on results from a Ricardian model where current (and future) agricultural production is analyzed as a function of temperature and precipitation. We project that the effect of overall climate change will be relatively benign until approximately 2030 and then worsen considerably. Our simulation results indicate that, over a 50-year period, the projected reduction in agricultural productivity may lead to 30 percent less average income, compared with the possible outcome in the absence of climate change. Autonomous adaptations that the farmers make and government policies in response will be crucial for Ethiopia’s future development.

Abstract: This paper examines positive externalities and complementarities between countries in the use of antiviral pharmaceuticals to mitigate pandemic influenza. It demonstrates the presence of treatment externalities in simple SIR (susceptible-infectious-recovered) models and simulations of a Global Epidemiological Model. In these simulations, the pandemic spreads from city to city through the international airline network and from cities to rural areas through ground transport. While most treatment benefits are private, spillovers suggest that it is in the self-interest of high-income countries to pay for some antiviral treatment in low-income countries. The most cost-effective policy is to donate doses to the country where the outbreak originates; however, donating doses to low-income countries in proportion to their populations may also be cost-effective. These results depend on the transmissibility of the flu strain, its start date, the efficacy of antivirals in reducing transmissibility, and the proportion of infectious people who can be identified and treated.

Abstract: This monograph is written for the numerate nonspecialist, and hopes to serve three purposes. First it gathers mathematical material from diverse but related fields of order statistics, records, extreme value theory, majorization, regular variation and subexponentiality. All of these are relevant for understanding fat tails, but they are not, to our knowledge, brought together in a single source for the target readership. Proofs that give insight are included, but for most fussy calculations the reader is referred to the excellent sources referenced in the text. Multivariate extremes are not treated. This allows us to present material spread over hundreds of pages in specialist texts in twenty pages. Chapter 5 develops new material on heavy tail diagnostics and gives more mathematical detail. Since variances and covariances may not exist for heavy tailed joint distributions, Chapter 6 reviews dependence concepts for certain classes of heavy tailed joint distributions, with a view to regressing heavy tailed variables. Second, it presents a new measure of obesity. The most popular definitions in terms of regular variation and subexponentiality invoke putative properties that hold at infinity, and this complicates any empirical estimate. Each definition captures some but not all of the intuitions associated with tail heaviness. Chapter 5 studies two candidate indices of tail heaviness basedon the tendency of the mean excess plot to collapse as data are aggregated. The probability that the largest value is more than twice the second largest has intuitive appeal but its estimator hasvery poor accuracy. The Obesity index is defined for a positive random variable X as:Ob(X) = P (X1 + X4 > X2 + X3|X1 = X2 = X3 = X4) , Xi independent copies of X. For empirical distributions, obesity is defined by bootstrapping. This index reasonably captures intuitions of tail heaviness. Among its properties, if a > 1 then Ob(X) < Ob(Xa). However, it does not completely mimic the tail index of regularly varying distributions, or the extreme value index. A Weibull distribution with shape 1/4 is more obese than a Pareto distribution with tail index 1, even though this Pareto has infinite mean and the Weibull’s moments are all finite. Chapter 5 explores properties of the Obesity index. Third and most important, we hope to convince the reader that fat tail phenomena pose real problems; they are really out there and they seriously challenge our usual ways of thinking about historical averages, outliers, trends, regression coefficients and confidence bounds among many other things. Data on flood insurance claims, crop loss claims, hospital discharge bills, precipitation and damages and fatalities from natural catastrophes drive this point home. Whilemost fat tailed distributions are ”bad”, research in fat tails is one distribution whose tail will hopefully get fatter.

Abstract: The value of mortality risk reduction is an important component of the benefits of environmental policies. In recent years, the number, scope, and quality of valuation studies have increased dramatically. Revealed preference studies of wage compensation for occupational risks, on which analysts have primarily relied, have benefited from improved data and statistical methods. Stated preference research has improved methodologically and expanded dramatically. Studies are now available for several health conditions associated with environmental causes, and researchers have explored many issues concerning the validity of the estimates. With the growing numbers of both types of studies, several meta-analyses have become available that provide insight into the results of both methods. Challenges remain, including better understanding of the persistently smaller estimates from stated preference than from wage differential studies and of how valuation depends on the individual’s age, health status, and characteristics of the illnesses most frequently associated with environmental causes.

Abstract: This paper reviews implementation of the risk management frameworks used by eight federal and foreign agencies—including the Minerals Management Service (MMS, now the Bureau of Ocean Energy Management, Regulation, and Enforcement, or BOEMRE)—and summarizes the features of a robust tolerable risk (TR) framework. A TR framework conceptually breaks risk into three categories—acceptable, unacceptable, and tolerable—separated by numerical boundaries. Most of the agencies surveyed in this review have adopted a TR or modified TR framework, but MMS (BOEMRE) generallyhas not (although the agency does use an Oil Spill Risk Model to assess spill probabilities and possible trajectories). The study argues that while numerical thresholds are not essential to risk management, theyprovide a transparent goal against which to benchmark practices, equipment, standards, and facilities, and would be a valuable tool for BOEMRE. We also recommend that BOEMRE develop better risk assessment and management guidance; identify and more systematically collect information for understanding and evaluating risks and safety performance; and strengthen performance-based risk management by adopting proven approaches, such as those used in Norway and the United Kingdom for offshore oil and gas development.