Strategic behavior and efficiency in a groundwater pumping differential game

In this paper socially optimal and private exploitation of a common property aquifer are compared. Open-loop and feedback equilibria in nonlinear strategies have been computed to characterize the private solution. The use of these two equilibrium concepts aIlows us to distinguish between cost and strategic externalities. The open-Loop solution captures only the cost externality, whereas the feedback solution captures both externalities. The results show that strategic behavior increases the overexploitation of the aquifer compared to the open-loop solution. However, if the groundwater storage capacity is large, the difference between the socIally optImal and private exploitation, characterized by a feedback equilibrium, is negligible and can be ignored for practical purposes. En este trabajo se comparan la explotación privada y socialmente óptima de un acuífero de propiedad común. Para caracterizar la solución privada se han calculado los equilibrios' openloop' y 'feedback' en estrategias no lineales. El uso de estos dos conceptos de equilibrio nos ha permitido distinguir entre efectos externos estratégicos y de coste. La solución 'open-loop' captura solamente el efecto externo de los costes mientras que la SolucIón 'feedback' captura ambos efectos externos. Los resultados muestran que el comportamiento estratégico aumenta la sobreexplotación del acuífero comparado con la solución 'open-loop' o Sin embargo, si la capacidad de almacenamiento del acuífero es grande, la diferencia entre la explotación privada y la socialmente óptima, caracterizada por un equilibrio 'feedback', es despreciable y puede Ignorarse para propósitos prácticos.Explotación de aguas subterráneas, recursos de propiedad común, efecto externo estratégico, juegos diferenciales, solución 'feedback', estrategias no lineales Groundwater exploitation, common property resources, strategic externality, differential games, feedback solution, nonlinear strategies

Optimal growth and land preservation

A model of optimal economic growth with a constant population subject to a constraint on the availability of land is presented. It takes account of the dual character of land as a production factor and as a consumption good (environmental amenities) by determining the optimal intertemporal allocation of land between productive and recreational uses. An extension of the analysis for the case of a growing population with endogenous growth based on human capital accumulation shows that if the rate of discount is not very low then there exists a set of balanced growth paths compatible with a constant allocation of land. En este trabajo se presenta un modelo de crecimiento económico óptimo con una población constante sujeto a una restricción sobre la disponibilidad de tierra. En el modelo se tiene en cuenta el carácter dual de la tierra como factor productivo y como bien de consumo para usos recreacionales y se determina cual es la asignación intertemporal óptima de la tierra entre estos dos usos. En la segunda parte del trabajo, se presenta una extensión del análisis para el caso de una población creciente con crecimiento endógeno basado en la acumulación de capital humano y se demuestra que si la tasa de descuento no es muy pequeña existe un conjunto de sendas de crecimiento equilibrado compatibles con una asignación constante de la tierra.Crecimiento óptimo, asignación intertemporal de la tierra, preservación medioambiental, crecimiento de la población, crecimiento endógeno, capital humano Optimal growth, intertemporal land allocation, environmental preservation, population growth, endogenous growth, human capital

An adaptation‑mitigation game: does adaptation promote participation in international environmental agreements?

This paper studies how the investment in adaptation can infuence the participation in an international environmental agreement (IEA) when countries decide in adaptation before they choose emissions. Three types of agreements are studied, a mitigation agreement for which countries coordinate their decisions only on emissions; an adaptation agreement for which there is only coordination when countries decide their levels of adaptation and a complete agreement when there is coordination in both emissions and adaptation levels. In every case, we assume that the degree of efectiveness of adaptation is bounded from above, in order words, adaptation can alleviate the environmental problem, but it cannot solve it by itself leading the vulnerability of the country to almost zero. Our frst results show that in our symmetric model where signatories select the same level of adaptation there are not signatory-signatory international externalities and the complete agreement coincides with the mitigation agreement, and moreover it does not matter when adaptation is chosen with respect to emissions. The main contribution of this paper is to show that the grand coalition could be stable for all types of agreement, but only for extremely high degrees of efectiveness of adaptation. If this condition is not satisfed, the model predicts low levels of membership. The standard result of three countries is found for the mitiga tion/complete agreement. For the adaptation agreement participation can be higher than three, but not higher than six countries. In any case, we can conclude that under reasonable values for the degree of efectiveness of adaptation, in our model adaptation does not pro mote participation in an IEA

El PROBLEMA DE LA PLANIFICACIÓN HIDROLÓGICA: UNA APLICACIÓN AL CASO ESPAÑOL

This paper is a theoretical analysis in terms of water transport costs, water rates, rentsand social welfare of three criteria applicable to the planning of water transfer systemsbetween rivers. The studied criteria have been: costs minimization of water transportation, establishing of water rates equal to average transport costs, and fixing of socially optimal rates. To illustrate the theoretical model we run a simulation based on available data of the country's water resources and their distribution in rivers, as well as on demand estimations previous to the Spanish Hydraulic Program. The simulation allows us to evaluate the social cost of the application of non optimal criteria. Este artículo consiste en un análisis teórico en términos de costes de transporte delagua, tarifas, renta del recurso y bienestar social de tres criterios aplicables en laplanificación de los trasvases intercuencas. Los criterios estudiados han sido el de laminimización de los costes de transporte del agua, el de la fijación de tarifas del agua iguales al coste de transporte medio, y el de la fijación de tarifas socialmente óptimas. Para ilustrar el análisis teórico se ha procedido a una simulación basada en los datos disponibles sobre recursos hidráulicos del país y su distribución por cuencas, así como en las estimaciones de demanda previas al Plan Hidrológico. Esta simulación nos ha permitido evaluar el coste social de la aplicación de criterios no óptimos.

Emission taxes and feed-in subsidies in the regulation of a polluting monopoly

The paper studies the use of emission taxes and feed-in subsidies for the regulation of a monopoly that can produce the same good with a technology that employs a polluting input and a clean technology. In the first part of the paper, we show that the efficient solution can be implemented combining a tax on emissions and a subsidy on clean output. The tax is lower than the environmental damages, and the subsidy is equal to the difference between the price and the marginal revenue. In the second part of the paper, the second-best tax and subsidy are also calculated solving a two-stage policy game between the regulator and the monopoly with the regulator acting as the leader of the game. We find that the second-best tax rate can be the Pigouvian tax, but only if the marginal costs of the clean technology are constant. Using a linear–quadratic specification of the model, we show that the clean output is larger when a feed-in subsidy is used than when the tax is applied, but the dirty output can be larger or lower depending on the magnitude of marginal costs of the clean technology and marginal damages. The same occurs for the net social welfare, although we find that for low enough marginal costs of the clean technology, the net social welfare is larger when a feed-in subsidy is used to promote clean output regardless the importance of the marginal damages

Long-run groundwater reserves under uncertainty

In this paper the long-run effects of demand and recharge uncertainty on the socially optimal management of groundwater reserves are studied. Demand uncertainty is modeled in a dynamic framework by letting the demand function shift randomly but continuously through time according to a random shock that follows a stochastic process. Likewise, uncertainty about natural recharge is characterized by identifying that variable as a stochastic process. The results show how the effects on long-run groundwater reserves depends crucially on the properties of the demand function. Basically, the long-run groundwater reserves increase (decrease) with an increase in uncertainty if the demand function is convex (concave). These effects occur because the random changes in demand and natural recharge cause an expected increase (decrease) in price depending on the curvature of the demand function. En este artículo se estudian los efectos a largo plazo de la incertidumbre de recarga y de demanda sobre la gestión socialmente óptima de las reservas de aguas subterráneas. La incertidumbre de demanda se trata en un marco dinámico dejando que la función de demanda cambie aleatoriamente pero continuamente a lo largo del tiempo de acuerdo con un shock aleatorio que sigue un proceso estocástico. Asimismo, la incertidumbre sobre la recarga natural se caracteriza identificando esa variable con un proceso estocático. Los resultados muestran como los efectos sobre las reservas de aguas subterráneas a largo plazo dependen crucialmente de las propiedades de la función de demanda. Básicamente las reservas de aguas subterráneasa largo plazo aumentan (disminuyen) con un aumento en la incertidumbre si la función de demanda es convexa (cóncava). Estos efectos ocurren porque los cambios aleatorios en la recarga natural y en la demanda provocan un aumento (disminución) esperado en el precio dependiendo de la curvatura de la función de demanda.Gestión de reservas de aguas subterráneas, incertidumbre de recarga y de demanda, control estocástico Groundwater management, demand and recharge uncertainty, stochastic control

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Height and body-mass index trajectories of school-aged children and adolescents from 1985 to 2019 in 200 countries and territories: a pooled analysis of 2181 population-based studies with 65 million participants

Summary Background Comparable global data on health and nutrition of school-aged children and adolescents are scarce. We aimed to estimate age trajectories and time trends in mean height and mean body-mass index (BMI), which measures weight gain beyond what is expected from height gain, for school-aged children and adolescents. Methods For this pooled analysis, we used a database of cardiometabolic risk factors collated by the Non-Communicable Disease Risk Factor Collaboration. We applied a Bayesian hierarchical model to estimate trends from 1985 to 2019 in mean height and mean BMI in 1-year age groups for ages 5–19 years. The model allowed for non-linear changes over time in mean height and mean BMI and for non-linear changes with age of children and adolescents, including periods of rapid growth during adolescence. Findings We pooled data from 2181 population-based studies, with measurements of height and weight in 65 million participants in 200 countries and territories. In 2019, we estimated a difference of 20 cm or higher in mean height of 19-year-old adolescents between countries with the tallest populations (the Netherlands, Montenegro, Estonia, and Bosnia and Herzegovina for boys; and the Netherlands, Montenegro, Denmark, and Iceland for girls) and those with the shortest populations (Timor-Leste, Laos, Solomon Islands, and Papua New Guinea for boys; and Guatemala, Bangladesh, Nepal, and Timor-Leste for girls). In the same year, the difference between the highest mean BMI (in Pacific island countries, Kuwait, Bahrain, The Bahamas, Chile, the USA, and New Zealand for both boys and girls and in South Africa for girls) and lowest mean BMI (in India, Bangladesh, Timor-Leste, Ethiopia, and Chad for boys and girls; and in Japan and Romania for girls) was approximately 9–10 kg/m2. In some countries, children aged 5 years started with healthier height or BMI than the global median and, in some cases, as healthy as the best performing countries, but they became progressively less healthy compared with their comparators as they grew older by not growing as tall (eg, boys in Austria and Barbados, and girls in Belgium and Puerto Rico) or gaining too much weight for their height (eg, girls and boys in Kuwait, Bahrain, Fiji, Jamaica, and Mexico; and girls in South Africa and New Zealand). In other countries, growing children overtook the height of their comparators (eg, Latvia, Czech Republic, Morocco, and Iran) or curbed their weight gain (eg, Italy, France, and Croatia) in late childhood and adolescence. When changes in both height and BMI were considered, girls in South Korea, Vietnam, Saudi Arabia, Turkey, and some central Asian countries (eg, Armenia and Azerbaijan), and boys in central and western Europe (eg, Portugal, Denmark, Poland, and Montenegro) had the healthiest changes in anthropometric status over the past 3·5 decades because, compared with children and adolescents in other countries, they had a much larger gain in height than they did in BMI. The unhealthiest changes—gaining too little height, too much weight for their height compared with children in other countries, or both—occurred in many countries in sub-Saharan Africa, New Zealand, and the USA for boys and girls; in Malaysia and some Pacific island nations for boys; and in Mexico for girls. Interpretation The height and BMI trajectories over age and time of school-aged children and adolescents are highly variable across countries, which indicates heterogeneous nutritional quality and lifelong health advantages and risks