On the Effects of Linking Cap‑and‑Trade Systems for CO2 Emissions

Linkage of national cap-and-trade systems is typically advocated by economists on a general analogy with the beneficial linkage of free-trade areas and on the specific grounds that linkage will ensure cost effectiveness among the linked jurisdictions. The paper analyses the less obvious effects of linkage with the bottom-up approach of the Paris Agreement where each country sets its nationally determined contribution for its own carbon dioxide ( CO 2) emissions. An appropriate and widely accepted specification for the damages of CO 2 emissions within a relatively short (say 5-10 year) period is that marginal damages for each jurisdiction are constant (although they can differ among jurisdictions). With this defensible assumption, the analysis is significantly clarified and yields simple closed-form expressions for all CO 2 permit prices. Some implications for linked and unlinked voluntary CO 2 cap-and-trade systems are derived and discussed. A numerical example illustrates the results.publishedVersio

International emissions trading in a non-cooperative equilibrium

Linkage of different countries’ domestic permit markets for pollution rights into a single international market alters governments’ incentives, and may trigger adjustments of the number of allocated permits. First, this work finds that in a non-cooperative equilibrium, international emissions trading is likely to increase the total emissions. Second, although trading will give a more efficient cross-country allocation of emissions, efficiency may nevertheless fall, because an already inefficiently low abatement level is likely to be further reduced. Third, we find that large countries are likely to experience losses from linking their permit markets to the permit markets of smaller countries.Emissions trading; efficiency; non-cooperative games

PPP-correction of the IPCC emission scenarios - does it matter?

Ian Castles and David Henderson have criticized IPCC’s Special Report on Emissions Scenarios (SRES) (IPCC, 2000) for using market exchange rates (MER) instead of purchasing power parities (PPP) when converting regional GDP into a common denominator. The consequence is that poor countries generally appear to be poorer than they actually are. An overstated income gap between rich and poor countries in the base year gives rise to projections of too high economic growth in the poor countries because the scenarios are constructed with the aim of reducing the income gap. Castles and Henderson claim that overstated economic growth means that greenhouse gas emissions are overstated as well. However, because closure of the emission intensity gap between the rich and the poor parts of the world is another important driving force in the scenarios, we argue that the use of MER in the SRES scenarios has not caused an overestimation of the global emission growth because the two types of errors effectively neutralize one another.Global warming; Emission scenarios; IPCC; PPP.