2009, Dolaptchiev, S.I., Klein, R.

Atmospheric phenomena such as the quasi-stationary Rossby waves, teleconnection patterns, ultralong persistent blockings and the polar/subtropical jet are characterized by planetary spatial scales, i.e. scales of the order of the earth's radius. This motivates our interest in the relevant physical processes acting on the planetary scales. Using an asymptotic approach, we systematically derive reduced model equations valid for atmospheric motions with planetary spatial scales and a temporal scale of the order of about 1 week. We assume variations of the background potential temperature comparable in magnitude with those adopted in the classical quasi-geostrophic theory. At leading order, the resulting equations include the planetary geostrophic balance. In order to apply these equations to the atmosphere, one has to prescribe a closure for the vertically averaged pressure. We present an evolution equation for this component of the pressure which was derived in a systematic way from the asymptotic analysis. Relative to the prognostic closures adopted in existing reduced-complexity planetary models, this new dynamical closure may provide for more realistic increased large-scale, long-time variability in future implementations. © 2008 Elsevier B.V. All rights reserved.

2009, Bauer, N., Edenhofer, O., Leimbach, M.

Endogenous technology scenarios for meeting low stabilization CO2 targets are derived in this study and assessed regarding emission reductions and mitigation costs. The aim is to indentify the most important technology options for achieving low stabilization targets. The significance of an option is indicated by its achieved emission reduction and the mitigation cost increase, if this option were not available. Quantitative results are computed using a global multi-regional hard-linked hybrid model that integrates the economy, the energy sector and the climate system. The model endogenously determines the optimal deployment of technologies subject to a constraint on climate change. The alternative options in the energy sector comprise the most important mitigation technologies: renewables, biomass, nuclear, carbon capture and sequestration (CCS), and biomass with CCS as well as energy efficiency improvements. The results indicate that the availability of CCS technologies and espec. biomass with CCS is highly desirable for achieving low stabilization goals at low costs. The option of nuclear energy is different: although it could play an important role in the primary energy mix, mitigation costs would only mildly increase, if it could not be expanded. Therefore, in order to promote prudent climate change mitigation goals, support of CCS technologies reduces the costs and-thus-is desirable from a social point of view. © 2009 Elsevier Ltd. All rights reserved.

2009, Held, Hermann, Edenhofer, Ottmar

Geological sequestration of CO2 on a massive scale implies that large area fractions of the underground could become flooded by CO2, imposing a unprecedented regulatory challenge to environmental authorities. Therefore we propose carbon sequestration bonds as complementary, market-based instruments that should further help to manage the risk of decadal-scale CO2 leakage. Such bond schemes address market failures that could occur if the investment behavior of operators under uncertainty differed from society’s preference. For a stylized setup we demonstrate that our bond system has the potential to simultaneously address regulatory challenges stemming from information asymmetries and diverging orders of preference.