The INDC counter, aggregation of national contributrions and 2°C trajectories

Rapport du groupe interdisciplinaire sur les contributions nationalesConsidering that limiting global warming to below 2°C implies a CO2 budget not to be exceeded and near-zero emissions by 21OO (IPCC), we can assess global 2030 greenhouse gas emissions implied by INDCs in comparison to long-term trajectories. Ahead of the COP21, we estimate that submitted INDCs would bring global greenhouse gas emissions in the range of 55 to 64 GtC02eq in 2030.Under this assumption,global emissions in 2030 are thus higher than the level of 51GtC0 2eq for the year 2012. However, this is not in contradiction with a peaking of global emissions that can only be expected after 2020, given in particular the projected dynamics of emissions in China and other developing countries.The published INDCs represent a significant step towards trajectories compatible with the 2°C goal,but remain insufficient to join trajectories presenting a reasonable probability of success.ln order to increase the chance of meeting the 2°C objective, the ambition of the short-term contributions needs to be strengthened in future negotiations.ln order to sustain a high pace in emissions reductions after 2030,structural measures are also needed, which, in order to have a rapi impact, should be prepared as early as possible. Continued efforts are needed to accelerate the development of low carbon solutions on the one hand,and demonstrate the feasibility of negative emissions on the other hand

L’utilisation des progiciels de statistiques dans la recherche en sciences humaines

L’un des principaux usages de l ’informatique en recherche se situe au niveau du traitement des données. De nos jours, les traitements courants de données s’effectuent essentiellement à l’aide de progiciels de statistiques. Les progiciels S.P.S.S. et S.A.S. sont les plus couramment utilisés en recherche en sciences sociales. Quelques avantages et désavantages de ces deux progiciels, ainsi que leurs possibiités et leurs limites d’utilisation sont d’abord présentés. Des recommandations relatives à une optimisation des bons usages d’un progiciel de statistiques sont ensuite élaborées : préalables, étapes de la programmation du progiciel et règles de programmation

Higher-level classification of the Archaea: evolution of methanogenesis and methanogens

We used a phylogenetic approach to analyze the evolution of methanogenesis and methanogens. We show that 23 vertically transmitted ribosomal proteins do not support the monophyly of methanogens, and propose instead that there are two distantly related groups of extant archaea that produce methane, which we have named Class I and Class II. Based on this finding, we subsequently investigated the uniqueness of the origin of methanogenesis by studying both the enzymes of methanogenesis and the proteins that synthesize its specific coenzymes. We conclude that hydrogenotrophic methanogenesis appeared only once during evolution. Genes involved in the seven central steps of the methanogenic reduction of carbon dioxide (CO2) are ubiquitous in methanogens and share a common history. This suggests that, although extant methanogens produce methane from various substrates (CO2, formate, acetate, methylated C-1 compounds), these archaea have a core of conserved enzymes that have undergone little evolutionary change. Furthermore, this core of methanogenesis enzymes seems to originate (as a whole) from the last ancestor of all methanogens and does not appear to have been horizontally transmitted to other organisms or between members of Class I and Class II. The observation of a unique and ancestral form of methanogenesis suggests that it was preserved in two independent lineages, with some instances of specialization or added metabolic flexibility. It was likely lost in the Halobacteriales, Thermoplasmatales and Archaeoglobales. Given that fossil evidence for methanogenesis dates back 2.8 billion years, a unique origin of this process makes the methanogenic archaea a very ancient taxon

Higher-level classification of the Archaea: evolution of methanogenesis and methanogens

We used a phylogenetic approach to analyze the evolution of methanogenesis and methanogens. We show that 23 vertically transmitted ribosomal proteins do not support the monophyly of methanogens, and propose instead that there are two distantly related groups of extant archaea that produce methane, which we have named Class I and Class II. Based on this finding, we subsequently investigated the uniqueness of the origin of methanogenesis by studying both the enzymes of methanogenesis and the proteins that synthesize its specific coenzymes. We conclude that hydrogenotrophic methanogenesis appeared only once during evolution. Genes involved in the seven central steps of the methanogenic reduction of carbon dioxide (CO2) are ubiquitous in methanogens and share a common history. This suggests that, although extant methanogens produce methane from various substrates (CO2, formate, acetate, methylated C-1 compounds), these archaea have a core of conserved enzymes that have undergone little evolutionary change. Furthermore, this core of methanogenesis enzymes seems to originate (as a whole) from the last ancestor of all methanogens and does not appear to have been horizontally transmitted to other organisms or between members of Class I and Class II. The observation of a unique and ancestral form of methanogenesis suggests that it was preserved in two independent lineages, with some instances of specialization or added metabolic flexibility. It was likely lost in the Halobacteriales, Thermoplasmatales and Archaeoglobales. Given that fossil evidence for methanogenesis dates back 2.8 billion years, a unique origin of this process makes the methanogenic archaea a very ancient taxon

L'objectif « zéro émissions nettes » de l'Accord de Paris : signification et implications

International audienc

Diversity of greenhouse gas emission drivers across European countries since the 2008 crisis

International audienceIn the context of climate change mitigation and the Paris Agreement, it is critical to monitor and understand the dynamics of greenhouse gas emissions over different regions of the world. In this study, we quantify the contributions of different drivers behind the observed emission decrease in Europe between 2009 and 2014. To this end, we build a novel dataset of deflated input-output tables for each of the 28 EU countries. This dataset enables us to conduct the first Structural Decomposition Analysis of emissions in European countries since the economic crisis. Our results show that the largest drivers of emissions have been the improvement in carbon intensity (−394 MtCO 2 e), largely offset by the economic recovery (+285 MtCO 2 e). However, other less intuitive drivers also played a significant role in the emission decline: changes in the production system (−104 MtCO 2 e), mostly driven by an increase in imports; the evolution of final demand patterns (−101 MtCO 2 e); a decrease in emissions due to household heating (−83 MtCO 2 e) and private transport (−24 MtCO 2 e), with a small offset from population growth (+39 MtCO 2 e). However, these aggregate figures mask significant variations between EU countries which we also document. This study highlights the importance of including changes in consumption patterns, trade and temperature anomalies in tracking and fostering progress towards the Paris Agreement goals