National audienceHuman activities are currently considered to emit 5.3 Tg N-N2O per year, mainly ... more National audienceHuman activities are currently considered to emit 5.3 Tg N-N2O per year, mainly from agriculture that accounts for around two-thirds of these emissions (UNEP, 2013). The atmospheric gas N2O is involved both in the greenhouse effect with a contribution on a molar basis of around 300 in relation to CO2 (Rodhe, 1990) and in ozone depletion (Ravishankara et al., 2009). The development of new approaches to increase agricultural efficiency and potential mitigation pathways are required in particular in the context of the continuing population growth. In soils, N2O is mainly produced through the microbial processes of denitrification and of nitrification. The last step of the denitrification process (N2O → N2) is currently the only known pathway for the terrestrial removal of N2O. N2O reduction is catalysed by the N2O reductase enzyme encoded by the nosZ gene (Viebrock and Zumft, 1988). The efficiency of soils to reduce N2O to N2 is highly variable. Soils with low N2O redu...
While the environmental innovations will play a key role in the transition towards a decarbonized... more While the environmental innovations will play a key role in the transition towards a decarbonized economy, their implementation is rather difficult to be realized in advanced economies. The techniques at stake imply for some of them scale and network economies, for others changes in habits and uses, with important technical and economic uncertainties. Developing countries can benefit as latecomers from these innovations without incurring their development costs, but they are reluctant to move towards a more decarbonized economic model if this evolution should reduce their growth and limit their development. From this point of view, mitigation techinques, especially Carbon Capture and Storage techniques, from fossil fuels (CCS) or bioenergy (BCCS) appear to be a promising way to reach stringent greenhouse gas reduction targets. They allow preserve the use of fossil fuels during a transition period towards a more decarbonized energy mix. These techniques are nevertheless submitted to ...
En présence d'actifs spécifiques, la réaction optimale d'une unité individuelle à des cho... more En présence d'actifs spécifiques, la réaction optimale d'une unité individuelle à des chocs exogènes est non linéaire et discontinue. Il faut donc reconstruire les grandeurs macroéconomiques, en agrégeant ces réponses individuelles discrètes. La spécificité des actifs affecte aussi les facteurs de production, qui doivent se partager la quasi rente tirée de leur collaboration. Le fonctionnement du marché externe a tendance à déprimer le prix du facteur non spécifique, flexible, pour rémunérer le facteur spécifique. Cette caractéristique se traduit par un sous investissement, des destructions excessives, et par une accentuation de la réponse cyclique d'une économie à facteurs spécifiques.
Résumé/Abstract L'époque récente a vu une accélération du processus de rattrapage technologi... more Résumé/Abstract L'époque récente a vu une accélération du processus de rattrapage technologique qui s' explique par une diffusion rapide, mais inégale, des anciennes et des nouvelles technologies dans les pays en développement. Ce rattrapage peut être analysé ...
National audienceHuman activities are currently considered to emit 5.3 Tg N-N2O per year, mainly ... more National audienceHuman activities are currently considered to emit 5.3 Tg N-N2O per year, mainly from agriculture that accounts for around two-thirds of these emissions (UNEP, 2013). The atmospheric gas N2O is involved both in the greenhouse effect with a contribution on a molar basis of around 300 in relation to CO2 (Rodhe, 1990) and in ozone depletion (Ravishankara et al., 2009). The development of new approaches to increase agricultural efficiency and potential mitigation pathways are required in particular in the context of the continuing population growth. In soils, N2O is mainly produced through the microbial processes of denitrification and of nitrification. The last step of the denitrification process (N2O → N2) is currently the only known pathway for the terrestrial removal of N2O. N2O reduction is catalysed by the N2O reductase enzyme encoded by the nosZ gene (Viebrock and Zumft, 1988). The efficiency of soils to reduce N2O to N2 is highly variable. Soils with low N2O redu...
While the environmental innovations will play a key role in the transition towards a decarbonized... more While the environmental innovations will play a key role in the transition towards a decarbonized economy, their implementation is rather difficult to be realized in advanced economies. The techniques at stake imply for some of them scale and network economies, for others changes in habits and uses, with important technical and economic uncertainties. Developing countries can benefit as latecomers from these innovations without incurring their development costs, but they are reluctant to move towards a more decarbonized economic model if this evolution should reduce their growth and limit their development. From this point of view, mitigation techinques, especially Carbon Capture and Storage techniques, from fossil fuels (CCS) or bioenergy (BCCS) appear to be a promising way to reach stringent greenhouse gas reduction targets. They allow preserve the use of fossil fuels during a transition period towards a more decarbonized energy mix. These techniques are nevertheless submitted to ...
En présence d'actifs spécifiques, la réaction optimale d'une unité individuelle à des cho... more En présence d'actifs spécifiques, la réaction optimale d'une unité individuelle à des chocs exogènes est non linéaire et discontinue. Il faut donc reconstruire les grandeurs macroéconomiques, en agrégeant ces réponses individuelles discrètes. La spécificité des actifs affecte aussi les facteurs de production, qui doivent se partager la quasi rente tirée de leur collaboration. Le fonctionnement du marché externe a tendance à déprimer le prix du facteur non spécifique, flexible, pour rémunérer le facteur spécifique. Cette caractéristique se traduit par un sous investissement, des destructions excessives, et par une accentuation de la réponse cyclique d'une économie à facteurs spécifiques.
Résumé/Abstract L'époque récente a vu une accélération du processus de rattrapage technologi... more Résumé/Abstract L'époque récente a vu une accélération du processus de rattrapage technologique qui s' explique par une diffusion rapide, mais inégale, des anciennes et des nouvelles technologies dans les pays en développement. Ce rattrapage peut être analysé ...
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