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Comment faire avancer la lutte contre la déforestation dans les pays en développement ?
2009
Karsenty A.
La conférence de Bali sur les changements climatiques a fait un pas vers le principe de rémunération de la réduction de la déforestation dans le cadre de la préparation du régime post-Kyoto. La déforestation contribuant à hauteur de 12-22% des émissions annuelles de CO2, la réduire est essentiel. Cependant, l'architecture et les modalités de mise en oeuvre du mécanisme nommé REDD (Réduction des émissions issues de la déforestation et de la dégradation) n'ont pas été définies et font l'objet de débats serrés, notamment sur la période de référence par rapport à laquelle mesurer la réduction de la déforestation au cours de la prochaine période d'engagement. Les pays qui considèrent que l'essentiel des épisodes de déboisement est derrière eux, plaident pour l'adoption d'une référence portant sur une période passée; à l'inverse, les pays à faible déboisement jusqu'à présent mais qui anticipent une déforestation accrue dans l'avenir, veulent pouvoir adopter une référence fondée sur un scénario tendanciel de déforestation future. L'autre divergence porte sur la nature des «récompenses»: crédits carbones échangeables sur le marché du même nom, ou argent issu d'un fonds spécial de lutte contre la déforestation ? On peut craindre que l'inclusion de REDD dans le marché du carbone n'entraîne une surabondance des permis d'émission et une baisse de leurs prix, compromettant l'efficacité, déjà toute relative, du système mis en place à Kyoto. On peut identifier trois problèmes récurrents avec l'architecture la plus évoquée pour REDD: la légitimité de l'extrapolation à partir de tendances historiques; la capacité d'estimation des scénarios de référence de type prédictif; enfin, la possibilité réelle d'imputer à différentes politiques publiques la baisse du taux de déforestation et d'en mesurer l'effet net. Le risque est réel pour qu'un tel mécanisme soit fortement générateur de réductions fictives d'émissions. II semble plus avisé de constituer un Fonds international contre la déforestation pour financer les politiques et les réformes structurelles nécessaires pour arrêter, à terme, la déforestation, ainsi que des programmes de paiements pour services environnementaux où les rémunérations iraient aux paysans plutôt qu'aux gouvernements. (Résumé d'auteur)
Show more [+] Less [-]Can C-budget of natural capital be restored through conservation agriculture in a tropical and subtropical environment?
2022
De Moraes Sa, Joao Carlos | Lal, Rattan | Briedis, Clever | De Oliveira Ferreira, Ademir | Tivet, Florent | Inagaki, Thiago Massao | Potma Gonçalves, Daniel Ruiz | Canalli, Lutécia Beatriz | Bürkner dos Santos, Josiane | Romaniw, Jucimare
Conservation agriculture through no-till based on cropping systems with high biomass-C input, is a strategy to restoring the carbon (C) lost from natural capital by conversion to agricultural land. We hypothesize that cropping systems based on quantity, diversity and frequency of biomass-C input above soil C dynamic equilibrium level can recover the natural capital. The objectives of this study were to: i) assess the C-budget of land use change for two contrasting climatic environments, ii) estimate the C turnover time of the natural capital through no-till cropping systems, and iii) determine the C pathway since soil under native vegetation to no-till cropping systems. In a subtropical and tropical environment, three types of land use were used: a) undisturbed soil under native vegetation as the reference of pristine level; b) degraded soil through continuous tillage; and c) soil under continuous no-till cropping system with high biomass-C input. At the subtropical environment, the soil under continuous tillage caused loss of 25.4 Mg C ha−1 in the 0–40 cm layer over 29 years. Of this, 17 Mg C ha−1 was transferred into the 40–100 cm layers, resulting in the net negative C balance for 0–100 cm layer of 8.4 Mg C ha−1 with an environmental cost of USD 1968 ha−1. The 0.59 Mg C ha−1 yr−1 sequestration rate by no-till cropping system promote the C turnover time (soil and vegetation) of 77 years. For tropical environment, the soil C losses reached 27.0 Mg C ha−1 in the 0–100 cm layer over 8 years, with the environmental cost of USD 6155 ha−1, and the natural capital turnover time through C sequestration rate of 2.15 Mg C ha−1 yr−1 was 49 years. The results indicated that the particulate organic C and mineral associate organic C fractions are the indicators of losses and restoration of C and leading C pathway to recover natural capital through no-till cropping systems.
Show more [+] Less [-]The Hungarian ILTER sites and their activities in 2002
2002
Kovacs-Lang, E. | Kertesz, M. | Toth, J. A.
The Hungarian ILTER Network consists of three sites representing the characteristic biomes in the country: lake Balaton ILTER site, Sikofut oak forest ILTER site, and the Kiskun sand forest-steppe ILTER site. Hungarian ecologists have developed broad multidisciplinary research projects, which can meet both the requirements of international research standards and the domestic needs of nature conservation and environment protection. Hungarian policy and decision makers have also recognised the importance of long-term ecological research. As a consequence different grants such as Hungarian R + D "Szechenyi", EU FWS Projects, OTKA and OTKA-NSF Projects, Joint grant of Ministry of Environment and the Hungarian Academy of Sciences were awarded in the last 2-3 years, what could create the basis of national and international research cooperations of Hungarian ILTER sites
Show more [+] Less [-]Needle surface structure and its relation to nutrient status of Norway spruce under the long-term air pollution influence
2002
Popierova, D. | Mankovska, B. (Forest Research Institute, Zvolen (Slovak Republic))
Emissions, especially of SO2 and to a certain degree of NOx have been reduced markedly in Slovakia during the 90s. Problems related to climate change and especially ozone are increasingly growing. The aim was to evaluate the long-term air pollution effect on forest ecosystems in mountain area with prevailing distribution of spruce through evaluation of spruce needle surface structure in relation to mineral nutrient status of trees. According to strong relationship between the coefficient of epicuticular wax degradation (Q) and accumulation of S and other elements it can be suggested that evaluation of needle surface structure by means of Q well reflects the surface status of needles
Show more [+] Less [-]Development trends of forest soils water regime under changing ecological conditions
2002
Tuzinsky, L. (Technical University, Zvolen (Slovak Republic). Forestry Faculty)
Forest ecosystems water balance research is very complicated because of forest influence upon individual components of the water balance. Global climate changes represent a real threat for forest ecosystems. In hydric area these changes concern especially thermal balance and resulting increased evapotranspiration, time and spatial distribution of precipitation
Show more [+] Less [-]Nitrous oxide emissions from a wheat field in response to elevated carbon dioxide concentration and open-top chamber enclosure
1998
Pleijel, H. | Sild, J. | Danielsson, H. | Klemedtsson, L. (IVL, P.O. Box 470 86, SE-402 58 Goteborg (Sweden))
Scots pine responses to CO2 enrichment - I. Ectomycorrhizal fungi and soil fauna
1996
Markkola, A.M. | Ohtonen, A. | Ahonen-Jonnarth, U. | Ohtonen, R. (Department of Biology, University of Oulu, P.O. Box 333, FIN-90571, Oulu (Finland))
Nitrogen deposition in Canada's Boreal Shield: implications for the Kyoto Protocol
1998
Brydges, T.G. (39 Elizabeth Street South, Brampton, Ontario, Canada L6Y 1RR2 (Canada))
Accelerated dehardening in bilberry (Vaccinium myrtillus L.) induced by a small elevation in air temperature
1997
Taulavuori, K. | Laine, K. | Taulavuori, E. | Pakonen, T. | Saari, E. (Department of Biology, Botany, PO Box 333, University of Oulu, FIN-90571 Oulu (Finland))