Évaluation et régulation de l’effet de serre d’origine agricole

Nous examinons la contribution du secteur agricole aux émissions de gaz à effet de serre ainsi que l’impact de mesures de régulation. À partir d’un modèle économique de l’offre agricole française à fort contenu technique, nous mesurons la contribution des activités animales et végétales à l’accumulation de méthane et de protoxyde d’azote et au stockage du carbone dans le sol et la partie aérienne des plantes. Nous donnons ensuite un éclairage prospectif sur la réaction à court et moyen terme de l’offre agricole à l’application de différents schémas de taxation. Dans un premier temps, nous donnons une appréciation de l’impact d’un schéma de premier rang et discutons de l’intérêt d’une incitation au reboisement des terres en jachère. Basées sur les données techniques disponibles, les taxes et primes reposent directement sur les niveaux d’émissions que l’agence environnementale est supposée mesurer parfaitement. Dans une optique de second rang fondée sur la taxation de facteurs observables à moindre coût, nous examinons ensuite l’effet : (i) d’une taxe sur l’alimentation achetée et (ii) d’une taxe sur l’animal. Le principal résultat est que l’incitation au reboisement constitue un instrument efficace de régulation de l’effet de serre d’origine agricole, alors que les schémas de taxe de second rang sur l’activité de production animale apparaissent relativement inefficaces.The aim of this paper is to study the modification of the greenhouse gas concentration in the atmosphere due to agricultural activities, and the impact of the implementation of regulation policy tools. From a supply-side model of the French agriculture, we estimate the contribution of cultivation and animal husbandry in terms of methane and nitrous oxide, taking also into account carbon storage in soils and plants. We then compare the effects of different tax schemes on agricultural supply in the short and mid run. We first focus on first best schemes. In this case, the taxes and subsidies are directly based on net emission levels that are assumed to be perfectly observed by the environmental agency. In this framework, we particularly discuss the opportunity of an incentive scheme proposed to producers in order to reafforest on set-aside land. Then we turn to the case of second best regulation tools based on the taxation of factors which are observable at lower cost, that is to say taxes on market feed and livestock. The incentive to reafforestation appears to be an effective means to regulate agricultural greenhouse gas emissions. It is much more socially acceptable than second best policy tools including taxes on activities derived from livestock

Évaluation et régulation de l’effet de serre d’origine agricole

The aim of this paper is to study the modification of the greenhouse gas concentration in the atmosphere due to agricultural activities, and the impact of the implementation of regulation policy tools. From a supply-side model of the French agriculture, we estimate the contribution of cultivation and animal husbandry in terms of methane and nitrous oxide, taking also into account carbon storage in soils and plants. We then compare the effects of different tax schemes on agricultural supply in the short and mid run. We first focus on first best schemes. In this case, the taxes and subsidies are directly based on net emission levels that are assumed to be perfectly observed by the environmental agency. In this framework, we particularly discuss the opportunity of an incentive scheme proposed to producers in order to reafforest on set-aside land. Then we turn to the case of second best regulation tools based on the taxation of factors which are observable at lower cost, that is to say taxes on market feed and livestock. The incentive to reafforestation appears to be an effective means to regulate agricultural greenhouse gas emissions. It is much more socially acceptable than second best policy tools including taxes on activities derived from livestock. Nous examinons la contribution du secteur agricole aux émissions de gaz à effet de serre ainsi que l’impact de mesures de régulation. À partir d’un modèle économique de l’offre agricole française à fort contenu technique, nous mesurons la contribution des activités animales et végétales à l’accumulation de méthane et de protoxyde d’azote et au stockage du carbone dans le sol et la partie aérienne des plantes. Nous donnons ensuite un éclairage prospectif sur la réaction à court et moyen terme de l’offre agricole à l’application de différents schémas de taxation. Dans un premier temps, nous donnons une appréciation de l’impact d’un schéma de premier rang et discutons de l’intérêt d’une incitation au reboisement des terres en jachère. Basées sur les données techniques disponibles, les taxes et primes reposent directement sur les niveaux d’émissions que l’agence environnementale est supposée mesurer parfaitement. Dans une optique de second rang fondée sur la taxation de facteurs observables à moindre coût, nous examinons ensuite l’effet : (i) d’une taxe sur l’alimentation achetée et (ii) d’une taxe sur l’animal. Le principal résultat est que l’incitation au reboisement constitue un instrument efficace de régulation de l’effet de serre d’origine agricole, alors que les schémas de taxe de second rang sur l’activité de production animale apparaissent relativement inefficaces.

Economic Analysis of Summer Fallow Management to Reduce Take-All and N-Leaching in a Wheat Crop Rotation

This paper addresses the question of summer cover crop adoption by farmers in presence of a risk of yield loss due to take-all disease and climate variability. To analyse the public incentives needed to encourage farmers to adopt summer cover crops as a means of reducing N leaching, we combine outputs from an economic, an epidemiological and an agronomic model. The economic model is a simple model of choice under uncertainty. The farmer is assumed to choose among a range of summer fallow managements and input uses on the basis of the expected utility criterion (HARA assumption) in presence of both climate and take all risks. The epidemiological model proposed by Ennaïfar et al. (2007) is used to determine the impact of take all on yields and N-uptake. The crop-soil model (STICS) is used to\ud compute yield developments and N-leaching under various management options and climatic conditions. These models are calibrated to match the conditions prevailing in Grignon, located in the main wheatgrowing\ud area in France. Eight management systems are examined: 4 summer fallow managements: 'wheat volunteers' (WV), 'bare soil' (BS), 'early mustard' (EM), 'late mustard' (LM), and 2 input intensities. We show that the optimal systems are BS (WV) when the take-all risk is (not) taken into account by agents. We then compute the minimum payment to each system such that it emerges in the optimum. We thus derive the required amounts of transfer needed to trigger catch crop adoption. The results of the Monte Carlo sensitivity analysis show that the ranking of management systems is robust over a wide range of input parameters

Biofuel Policies in the Presence of Environmental Externalities Preliminary Version (Please do not quote)

Abstract The objective of this paper is to compare, in a general equilibrium setting with three goods, the relative efficiency of biofuel subsidy and biofuel mandate policies with the laissez-faire solution. The outcomes of these institutional arrangements are also compared to that of the optimal solution. This analysis takes into account several environmental externalities such as those associated with the production of biofuels. Our numerical results, applied to the biodiesel policy of France in 2006, show that both policies decrease the utility of the representative consumer compared to the laissez-faire solution. The biofuel subsidy policy also increases overall emissions

Responsiveness and clinical utility of the geriatric self-efficacy index for urinary incontinence

OBJECTIVES: To report on the responsiveness testing and clinical utility of the 12-item Geriatric Self-Efficacy Index for Urinary Incontinence (GSE-UI). DESIGN: Prospective cohort study. SETTING: Six urinary incontinence (UI) outpatient clinics in Quebec, Canada. PARTICIPANTS: Community-dwelling incontinent adults aged 65 and older. MEASUREMENTS: The abridged 12-item GSE-UI, measuring older adults' level of confidence for preventing urine loss, was administered to all new consecutive incontinent patients 1 week before their initial clinic visit, at baseline, and 3 months posttreatment. At follow-up, a positive rating of improvement in UI was ascertained from patients and their physicians using the Patient's and Clinician's Global Impression of Improvement scales, respectively. Responsiveness of the GSE-UI was calculated using Guyatt's change index. Its clinical utility was determined using receiver operating curves. RESULTS: Eighty-nine of 228 eligible patients (39.0%) participated (mean age 72.6+5.8, range 65–90). At 3-month follow-up, 22.5% of patients were very much better, and 41.6% were a little or much better. Guyatt's change index was 2.6 for patients who changed by a clinically meaningful amount and 1.5 for patients having experienced any level of improvement. An improvement of 14 points on the 12-item GSE-UI had a sensitivity of 75.1% and a specificity of 78.2% for detecting clinically meaningful changes in UI status. Mean GSE-UI scores varied according to improvement status (P<.001) and correlated with changes in quality-of-life scores (r=0.7, P<.001) and reductions in UI episodes (r=0.4, P=.004). CONCLUSION: The GSE-UI is responsive and clinically useful

IFMIF, the European–Japanese efforts under the Broader Approach agreement towards a Li(d,xn) neutron source: Current status and future options

The necessity of a neutron source for fusion materials research was identified already in the 70s. Though neutrons induced degradation present similarities on a mechanistic approach, thresholds energies for crucial transmutations are typically above fission neutrons spectrum. The generation of He via 56Fe (n,α) 53Cr in future fusion reactors with around 12 appm/dpa will lead to swelling and structural materials embrittlement. Existing neutron sources, namely fission reactors or spallation sources lead to different degradation, attempts for extrapolation are unsuccessful given the absence of experimental observations in the operational ranges of a fusion reactor. Neutrons with a broad peak at 14 MeV can be generated with Li(d,xn) reactions; the technological efforts that started with FMIT in the early 80s have finally matured with the success of IFMIF/EVEDA under the Broader Approach Agreement. The status today of five technological challenges, perceived in the past as most critical, are addressed. These are: 1. the feasibility of IFMIF accelerators, 2. the long term stability of lithium flow at IFMIF nominal conditions, 3. the potential instabilities in the lithium screen induced by the 2 × 5 MW impacting deuteron beam, 4. the uniformity of temperature in the specimens during irradiation, and 5. the validity of data provided with small specimens. Other ideas for fusion material testing have been considered, but they possibly are either not technologically feasible if fixed targets are considered or would require the results of a Li(d,xn) facility to be reliably designed. In addition, today we know beyond reasonable doubt that the cost of IFMIF, consistently estimated throughout decades, is marginal compared with the cost of a fusion reactor. The less ambitious DEMO reactor performance being considered correlates with a lower need of fusion neutrons flux; thus IFMIF with its two accelerators is possibly not needed since with only one accelerator as the European DONES or the Japanese A-FNS propose, the present needs > 10 dpa/fpy would be fulfilled. World fusion roadmaps stipulate a fusion relevant neutron source by the middle of next decade, the success of IFMIF/EVEDA phase is materializing this four decades old dream