ALAIN AYONG LE KAMA

Mitigation and adaptation are not enough: turning to emissions reduction abroad

Alain Ayong Le Kama, Aude Pommeret

Résumé

In this paper we focus on a long-term dynamic analysis of the optimal adaptation/mitigation mix in the presence of a pollution threshold above which adaptation is no longer efficient. We account for accumulation in abatement capital, greenhouse gases, and adaptation capital in order to better capture the arbitrage between abatement and adaptation investments. Pollution damages arise from the emissions due to the country consumption but also from the emissions of the rest of the world (ROW). A pollution threshold is then introduced, above which adaptation is no longer efficient. We obtain that if this threshold is lower than the steady-state level of pollution, there is no way for the modeled economy to avoid it. In particular, such a situation will appear if the ROW's emissions are high. Next step is then to introduce another type of investment allowing for lower ROW pollution ie. emissions eduction abroad through CDM for instance. We obtain that CDM may be a means to avoid a pollution threshold above which adaptation becomes of no use.

Mot(s) clé(s)

Climate change, mitigation, adaptation, CDM, pollution threshold.

Water Conservation versus Soil Salinity Control

Alain Ayong Le Kama, Agnès Tomini

Résumé

This paper tackles the increasingly significant problem of irrigation-induced soil salinity within a groundwater management model. Irrigation can result not only in heavier salt concentrations, but also in the removal of salt from the soil through return flows. Given these contradictory observations, we are interested in the effects on soil salt concentration if irrigation efficiency is improved. We develop a model of salt concentration patterns in both soil and groundwater. We introduce a negative externality to the production process by assuming that soil degradation due to higher soil salinity affects total factor productivity. Within this framework, we show that in the presence of this externality, increasing irrigation efficiency can lead to higher or lower soil salt concentration, depending on the social cost of transferring salt from one reservoir to another.

Mot(s) clé(s)

Groundwater Management, Optimal Control of Water Consumption, Soil Salinity