Search

Greenhouse gas emission scenarios are key to analyse of human interference with the climate system. They are mainly produced by one category of computer models: Integrated Assessment Models (IAMs). We analyse how IAM research organised into a community around the production of socio-economic scenarios during the preparation of the IPCC AR5 (2005-2014). We seek to describe the co-emergence of a research community, its instruments, and its domain of applicability. We highlight the role of the IPCC process in the making of the IAM community, showing how IAMs worked their way to an influent position. We then survey three elements of the repertoire that served to organise collective work on scenarios in interaction with the IPCC and the European Union, and which now frames the community and its epistemic practices. This repertoire needs to articulate epistemic practices with the pursuit of policy relevance, which shows how epistemic communities and patterns of co-production materialise in practical arrangements. [ABSTRACT FROM AUTHOR]

The Paris COP-21 reached a climate agreement on 2-degree global emissions stabilisation target. However, the likelihood of successfully implementing a legally binding global climate treaty will depend to a large degree on the macroeconomic impacts of different policy options on developing and emerging economies. It is thus crucial to evaluate the transition costs of implementing different climate policy architectures under socioeconomic and technological uncertainties from a multiregional perspective. Here we use a hybrid computable general equilibrium model, in which sub-optimalities, infrastructural inertia and technological uncertainties are explicitly introduced, to quantify the trajectories of variation in transitions costs under a range of climate policy scenarios in both Annex I and developing nations. The policy architectures are based around the implementation of the ‘streamlined Paris Pledges’ (SPP) in developing countries with a particular focus on China and India. Our results indicate that the distributional effects should be taken into account by policymakers through extension of SPP to 2050 as global climate policies may have asymmetrical economic impacts between Annex I and developing countries. A first-best policy of global cap-and-trade scheme alone could be welfare-deteriorating for some parties, reflected by a significant reduction in macroeconomic growth rate over the course of the next decades. Modelling results also suggest that articulating both global and national policies in a multiregional climate deal can provide a palatable solution for countries like China as this would allow for significant reduction in the economic losses associated with a unique-carbon-price global climate policy. This hybrid approach is also aligned with specific development priorities in developing and emerging countries by providing flexibility to their domestic policy framework, which expects to facilitate the transition to low carbon growth trajectory by encouraging intersectoral coordination. Last, procrastination of technical change and delayed structural reform for decarbonising economy would entail significantly higher transition costs for developing countries in case of stringent climate policy due to the economic competitiveness forgone as a result of exorbitant carbon prices in the longer term. Relevant policy options and research perspectives are discussed accordingly. [ABSTRACT FROM AUTHOR]

Co-benefits of climate policies: a potential keystone of climate negotiations? This paper analyzes the challenges related to the assessment of co-benefits of climate policies underpinned by the implementation of multi-objective policies which seek synergies between climate policies and other development objectives (poverty alleviation, employment, health etc.). The analysis highlights the increasing interest in co-benefits in the latest 5th IPCC report, in particular by integrated models. Nevertheless, the quantified evaluation of co-benefits is still confronted to several methodological limitations which reduce the scope of co-benefits, particularly at the global level. In a growing context of climate-development approaches in climate negotiations, this article insists on the need to also assess cobenefits of other policies which induce a significant part of GHG emissions. Considering climate policies focused only on Greehouse Gases emissions reduction limits the range of policy instruments to carbon taxation, tradable carbon emissions permits or dedicated mitigation and adaptation funds. This also hinders the integration of climate objectives in non-climate policies. Analyzing impacts of development policies on Green Gases emissions in the form of co-benefits requires to broaden the range of policy instruments and to take into account other drivers of emissions such as land dynamics. Including these mechanisms in integrated models therefore represents new scientific frontiers for integrated models in the coming years. [ABSTRACT FROM AUTHOR]