Cause, conseguenze e strategie di mitigazione Proponiamo il primo di una serie di articoli in cui affronteremo l’attuale problema dei mutamenti climatici. Presentiamo il documento redatto, votato e pubblicato dall’Ipcc - Comitato intergovernativo sui cambiamenti climatici - che illustra la sintesi delle ricerche svolte su questo tema rilevante.

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Climate Change 2007: The Physical Science Basis.

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Economics of natural resources and the environment

This article proposes contemporary best-practice recommendations for stated preference (SP) studies used to inform decision making, grounded in the accumulated body of peer-reviewed literature. These recommendations consider the use of SP methods to estimate both use and non-use (passive-use) values, and cover the broad SP domain, including contingent valuation and discrete choice experiments. We focus on applications to public goods in the context of the environment and human health but also consider ways in which the proposed recommendations might apply to other common areas of application. The recommendations recognize that SP results may be used and reused (benefit transfers) by governmental agencies and nongovernmental organizations, and that all such applications must be considered. The intended result is a set of guidelines for SP studies that is more comprehensive than that of the original National Oceanic and Atmospheric Administration (NOAA) Blue Ribbon Panel on contingent valuation, is more germane to contemporary applications, and reflects the two decades of research since that time. We also distinguish between practices for which accumulated research is sufficient to support recommendations and those for which greater uncertainty remains. The goal of this article is to raise the quality of SP studies used to support decision making and promote research that will further enhance the practice of these studies worldwide.

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Contemporary Guidance for Stated Preference Studies

In this paper recent developments in the estimation of frontier functions and the measurement of efficiency are surveyed, and the potential applicability of these methods in agricultural economics is discussed. Frontier production, cost and profit functions are discussed, along with the construction of technical, allocative, scale and overall efficiency measures relative to these estimated frontiers. The two primary methods of frontier estimation, econometric and linear programming, are compared. A survey of recent applications of frontier methods in agriculture is also provided. (This abstract was borrowed from another version of this item.)

Recent Developments in Frontier Modelling and Efficiency Measurement

Drought is a complex natural hazard that impacts ecosystems and society in many ways. Many of these impacts are associated with hydrological drought (drought in rivers, lakes, and groundwater). It is, therefore, crucial to understand the development and recovery of hydrological drought. In this review an overview is given of the current state of scientific knowledge of definitions, processes, and quantification of hydrological drought. Special attention is given to the influence of climate and terrestrial properties (geology, land use) on hydrological drought characteristics and the role of storage. Furthermore, the current debate about the use and usefulness of different drought indicators is highlighted and recent advances in drought monitoring and prediction are mentioned. Research on projections of hydrological drought for the future is summarized. This review also briefly touches upon the link of hydrological drought characteristics with impacts and the issues related to drought management. Finally, four challenges for future research on hydrological drought are defined that relate international initiatives such as the Intergovernmental Panel on Climate Change (IPCC) and the ‘Panta Rhei’ decade of the International Association of Hydrological Sciences (IAHS). WIREs Water 2015, 2:359–392. doi: 10.1002/wat2.1085

For further resources related to this article, please visit the WIREs website.

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Hydrological drought explained

Deficit irrigation (DI) is an agricultural practice in which the volume of irrigation water applied during the crop cycle is below the irrigation requirements for maximum production, the aim of which is to increase irrigation water productivity. Most research on this technique has focused on agronomic strategies while the economic and environmental consequences have received little attention. This study aims to shed some light on this matter and presents preliminary results regarding the implications of DI with respect to the sustainable use of water resources. The analysis is based on the DPSIR analytical framework (Driving force/Pressure/State/Impact/Response) and the microeconomics of DI. The case study focuses on intensive olive groves in the Guadalquivir river basin in Southern Spain (where olive cultivation accounts for 50% of the total irrigated area). The analysis shows that the widespread use of DI practices, which is the farmers’ response to a decreasing net water supply and falling farm incomes (driving force) in the context of a mature water economy, may help to break the DPSIR chain of causality, provided that there are restrictions on any expansion in irrigated area. They can, thus, play a role in achieving sustainable water use. Conversely, demand and supply (regulator) responses involving raising the price of water would lead to higher pressures on the resource and represent a negative driving force in our DPSIR model.

https://www.mdpi.com/2071-1050/9/7/1144/pdf

Sustainability Implications of Deficit Irrigation in a Mature Water Economy: A Case Study in Southern Spain

Farmers’ stated preference analysis towards resources use under alternative policy scenarios

Estimating demand for irrigation water in European Mediterranean countries through MCDM models.

Price Volatility and Water Demand in Agriculture. A Case Study of the Guadalquivir River Basin (Spain)

This research measures the Azores dairy farms’ technical efficiency by applying a non-parametric efficiency analysis to a panel data of 122 dairy farms from the Azores, Portugal, for 1996. The analysis used DEA with constant and variable returns to scale models, with an input-oriented model approach. Two outputs (milk production and subsidies) and three inputs (agricultural area, number of dairy cows and variable and fixed cost) were considered relevant. The results suggest that the average technical efficiency is very low (66.4%) compared with published research data, and only a few (7%) dairy farms were found to be efficient.

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Julio Berbel

Papers

Sustainability Implications of Deficit Irrigation in a Mature Water Economy: A Case Study in Southern Spain

Farmers’ stated preference analysis towards resources use under alternative policy scenarios

Estimating demand for irrigation water in European Mediterranean countries through MCDM models.

Price Volatility and Water Demand in Agriculture. A Case Study of the Guadalquivir River Basin (Spain)

An Application of Data Envelopment Analysis (DEA) in Azores Dairy Farms