Les nouveaux scénarios socio-économiques pour la recherche sur le changement climatique

National audienceThe scientific community is developing a new generation of scenarios to inform the choices we have to make when it comes to responding to climate change. This new generation of scenarios integrates more fully the mechanisms that regulate climate and provides insights to spatial and temporal resolutions unexplored in previous exercises. In addition, it gives a framework for integrating explicit climate policies for mitigation and adaptation, which allows assessing the benefits and costs of climate policies in different socio-economic scenarios. Finally, it introduces a new way of working that strengthens the collaboration between different research communities on climate change.La communauté scientifique est en train d'élaborer une nouvelle génération de scénarios pour éclairer les choix que nous avons à faire face au changement climatique. Cette nouvelle génération de scénarios permet d'intégrer de manière plus complète les mécanismes qui régissent le climat et de donner des éclairages à des résolutions spatiales et temporelles inexplorées dans les exercices précédents. Par ailleurs, elle donne un cadre pour intégrer explicitement les politiques climatiques d'atténuation et d'adaptation, ce qui ouvre la possibilité d'évaluer les bénéfices et les coûts des politiques climatiques selon différents scénarios socio-économiques. Enfin, elle met en place une nouvelle façon de travailler qui renforce la collaboration entre les différentes communautés de recherche sur le changement climatique

How CO2 Capture and Storage Can Mitigate Carbon Leakage

Most CO2 abatement policies reduce the demand for fossil fuels and therefore their price in international markets. If these policies are not global, this price decrease raises emissions in countries without CO2 abatement policies, generating “carbon leakage”. On the other hand, if the countries which abate CO2 emissions are net fossil fuel importers, they benefit from this price decrease, which reduces the abatement cost. In contrast, CO2 capture and storage (CCS) does not reduce fossil fuel demand, therefore it generates neither this type of leakage nor this negative feedback on abatement costs. We quantify these effects with the global hybrid general equilibrium model Imaclim-R and show that they are quantitatively important. Indeed, for a given unilateral abatement in OECD countries, leakage is more than halved in a scenario with CCS included among the abatement options, compared to a scenario prohibiting CCS. We show that the main reason for this difference in leakage is the above-mentioned international fossil fuel price feedback. This article does not intend to assess the desirability of CCS, which has many other pros and cons. It just identifies a consequence of CCS that should be taken into account, together with many others, when deciding to what extent CCS should be developed.CO2 Capture and Storage, Carbon Leakage

Downscaling long term socio-economic scenarios at city scale: A case study on Paris

International audienceThe NEDUM-2D model is used to downscale four global socioeconomic scenarios at city scale and simulate the evolution of the Paris urban area between 1900 and 2100. It is based on a dynamic extension of the classical urban economic theory, to explain the spatial distribution of land and real estate values, dwelling surfaces, population density and buildings heights and density. A validation over the 1900-2010 period shows that the model reproduces available data and captures the main determinants of city shape evolution. From four global scenarios and additional local inputs, 32 local scenarios are created and analyzed. Main drivers of urban sprawl and climate and flood vulnerability appear to be local demographic growth and local policies; global factors, such as energy and transport prices, even including possible peak-oil and carbon taxes, have only a limited influence on them. Conversely, transport-related greenhouse gases emissions are mainly driven by global factors, namely vehicle efficiency changes, not by land use. As a consequence, very strict urban policies — including reconstruction — would become necessary to control emissions from urban transportation if technologies reveal unable to do so. These scenarios are a useful input for the design and assessment of mitigation and adaptation policies at local scale

Decarbonizing development: three steps to a zero-carbon future

This report lays out three steps for a smooth transition to a zero-carbon future and provides data, examples and policy advice to help countries makes the shift. Overview Getting to zero net emissions and stabilizing climate change starts with planning for the long-term future and not stopping at short-term goals. It means getting prices right as part of a broad policy package that can trigger changes in both investments and behaviors, and it requires smoothing the transition for those most affected. A new World Bank report walks policymakers through those three steps with data, examples and policy advice to help put countries on a path to decarbonizing their development in a smooth and orderly way. The solutions exist, and they are affordable – if governments take action today, the report says

Monetary compensations in climate policy through the lens of a general equilibrium assessment The case of oil-exporting countries

International audienceThis paper investigates the compensations that major oil producers have claimed for since the Kyoto Protocol in order to alleviate the adverse impacts of climate policy on their economies. The amount of these adverse impacts is assessed through a general equilibrium model which endogenizes both the reduction of oil exportation revenues under international climate policy and the macroeconomic effect of carbon pricing on Middle-East's economy. We show that compensating the drop of exportation revenues does not offset GDP and welfare losses because of the time profile of the general equilibrium effects. When considering instead compensation based on GDP losses, the effectiveness of monetary transfers proves to be drastically limited by general equilibrium effects in opened economies. The main channels of this efficiency gap are investigated and its magnitude proves to be conditional upon strategic and policy choices of the Middle-East. This leads us to suggest that other means than direct monetary compensating transfers should be discussed to engage the Middle-East in climate policies

Building SSPs for climate policy analysis: a scenario elicitation methodology to map the space of possible future challenges to mitigation and adaptation

International audienceThe scientific community is now developing a new set of scenarios, referred to as Shared Socio-economic Pathways (SSPs) that will be contrasted along two axes: challenges to mitigation, and challenges to adaptation. This paper proposes a methodology to develop SSPs with a "backwards" approach based on (i) an a priori identification of potential drivers of mitigation and adaptation challenges; (ii) a modelling exercise to transform these drivers into a large set of scenarios; (iii) an a posteriori selection of a few SSPs among these scenarios using statistical cluster-finding algorithms. This backwards approach could help inform the development of SSPs to ensure the storylines focus on the driving forces most relevant to distinguishing between the SSPs. In this illustrative analysis, we find that energy sobriety, equity and convergence prove most important towards explaining future difference in challenges to adaptation and mitigation. The results also demonstrate the difficulty in finding explanatory drivers for a middle scenario (SSP2). We argue that methodologies such as that used here are useful for broad questions such as the definition of SSPs, and could also be applied to any specific decisions faced by decision-makers in the field of climate change

Venturing into Uncharted Financial Waters : an Essay on Climate-Friendly Finance

This paper explores links between global financial imbalances and tensions around reserve currency along with climate change. Currently, risky levels of private and public debts co-exist with vast amounts of savings which "do not know where to go." Long-term climate-oriented financial products could enhance investors' confidence in low carbon projects (LCP) and channel to them large amounts of private savings. The paper outlines a financial architecture, the cornerstone of which is an agreement on the Social Cost of Carbon (SCC) integrated into a project's appraisal and acting as a surrogate for a carbon price. This SCC would be the value of carbon certificates issued by the government, and delivered to Banks to issue credit facilities reducing the risk-adjusted costs of LCPs. These carbon certificates could be gradually transformed into legal reserve assets of the Banks after verification of the reality of the projects. Finally, the paper considers whether such certificates would be recognized as genuine international reserve assets, backed by the rising value of carbon over time. It shows how emerging countries could then diversify their foreign exchange reserves through an asset based on the international recognition of climate as a global public good.L'accord de Cancun reconnaît qu'en l'absence de prix du carbone, la finance climat est un outil décisif pour aligner les objectifs de développement sur des objectifs de décarbonation de l'économie. Une part conséquente de l'épargne mondiale devrait être redirigée vers les projets bas carbone (PBCs) pour éviter aux pays émergents de s'enfermer dans des trajectoires de développement intensives en carbone. Dans ce papier nous élaborons une architecture financière globale qui faciliterait à la fois la conclusion d'un large accord climatique entre les pays et une forte augmentation des flux de capitaux dédiés à la finance climat. Nous examinons d'abord les conditions nécessaires pour que la finance climat déclenche un cercle vertueux de confiance parmi les investisseurs. Puis nous montrons qu'un accord lors d'une future COP sur la " valeur sociale du carbone " (VSC) et la reconnaissance par les banques centrales d'un actif carbone (qui découle de la VSC) comme nouvelle réserve légale sont deux conditions clés pour produire un effet de levier sur l'investissement dans les PBCs. Nous tirons enfin les enseignements de la crise financière et expliquons pourquoi les mécanismes proposés ne pourront déployer leur pleine capacité que si le FMI est autorisé à reconnaître les actifs carbone comme de nouveaux actifs de réserve internationaux en contrepartie des PBCs réalisés par ses pays membres. En outre, cet instrument monétaire pourrait contribuer à apaiser les inquiétudes actuelles sur le futur immédiat de la croissance économique et celui de la stabilité des systèmes financiers et monétaires mondiaux

Climate policies as a hedge against the uncertainty on future oil supply

International audienceDespite the inextricable link between oil scarcity and climate change, the interplay between these two issues is paradoxically an underworked area. This article uses a global energy-economy model to address the link between future oil supply and climate change and assesses in a common framework both the costs of climate policies and oil scarcity. It shows that, in the context of a limited and uncertain amount of ultimately recoverable oil resources, climate policies reduce the world vulnerability to peak oil. Climate policies, therefore, appear as a hedging strategy against the uncertainty on oil resources, in addition to their main aim of avoiding dangerous climate change. This co-benefit is estimated at the net present value of US$11,500 billion. Eventually, reducing the risk of future economic losses due to oil scarcity may appear as a significant side-benefit of climate policies to many decision-makers

Eight grand challenges in socio-environmental systems modeling

Modeling is essential to characterize and explore complex societal and environmental issues in systematic and collaborative ways. Socio-environmental systems (SES) modeling integrates knowledge and perspectives into conceptual and computational tools that explicitly recognize how human decisions affect the environment. Depending on the modeling purpose, many SES modelers also realize that involvement of stakeholders and experts is fundamental to support social learning and decision-making processes for achieving improved environmental and social outcomes. The contribution of this paper lies in identifying and formulating grand challenges that need to be overcome to accelerate the development and adaptation of SES modeling. Eight challenges are delineated: bridging epistemologies across disciplines; multi-dimensional uncertainty assessment and management; scales and scaling issues; combining qualitative and quantitative methods and data; furthering the adoption and impacts of SES modeling on policy; capturing structural changes; representing human dimensions in SES; and leveraging new data types and sources. These challenges limit our ability to effectively use SES modeling to provide the knowledge and information essential for supporting decision making. Whereas some of these challenges are not unique to SES modeling and may be pervasive in other scientific fields, they still act as barriers as well as research opportunities for the SES modeling community. For each challenge, we outline basic steps that can be taken to surmount the underpinning barriers. Thus, the paper identifies priority research areas in SES modeling, chiefly related to progressing modeling products, processes and practices

Quantum materials for energy-efficient neuromorphic computing

Neuromorphic computing approaches become increasingly important as we address future needs for efficiently processing massive amounts of data. The unique attributes of quantum materials can help address these needs by enabling new energy-efficient device concepts that implement neuromorphic ideas at the hardware level. In particular, strong correlations give rise to highly non-linear responses, such as conductive phase transitions that can be harnessed for short and long-term plasticity. Similarly, magnetization dynamics are strongly non-linear and can be utilized for data classification. This paper discusses select examples of these approaches, and provides a perspective for the current opportunities and challenges for assembling quantum-material-based devices for neuromorphic functionalities into larger emergent complex network systems