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This paper explores the potential for bio-energy production, and the implications of different values for the attainability of low stabilization targets. The impact of scenarios of future land use, yield improvements for bio-energy and available land under different sustainability assumptions (protection of biodiversity, risks of water scarcity and land degradation) are explored. Typical values for sustainable potential of bio-energy production are around 50-150 EJ in 2050 and 200-400 EJ in 2100. Higher bio-energy potential requires a development path with high agricultural yields, dietary patterns with low meat consumption, a low population and/or accepting high conversion rates of natural areas. Scenario analysis using four different models shows that low stabilization levels may be achieved with a bio-energy potential of around 200 EJ p.a. in such scenarios, bio-energy is in most models mainly used outside the transport sector. [ABSTRACT FROM AUTHOR]

In order to limit global mean temperature increase to less than 2°C, long-term greenhouse gas concentrations must remain low. This paper discusses how such low concentrations can be reached, based on results from the IMAGE modelling framework (including TIMER and FAIR). We show that the attainability of low greenhouse gas concentration targets, in particular 450 and 400 ppm CO2 equivalent critically depends on model assumptions, such as bio-energy potentials. Under standard model assumptions, these targets can be reached, although the lowest requires the use of bio-energy in combination with carbon-capture-and-storage. Regions are affected differently by ambitious climate policies in terms of energy and land use, although stringent emission reductions will be required in all regions. Resulting co-benefits of climate policy (such as energy security and air pollution) are also different across world regions. [ABSTRACT FROM AUTHOR]

Model analysis within the ADAM project has shown that achieving low greenhouse gas concentration levels, e.g. at 400ppm CO2-e is technologically feasible at costs of a few percent of GDP. However, models simplify the dynamics involved in implementing climate policy and the results depend on critical model assumptions such as global participation in climate policy and full availability of current and newly evolving technologies. The design of a low stabilization policy regime in the real world depends on factors that can only be partly covered by models. In this context, the paper reflects on limits of the integrated assessment models used to explore climate policy and addresses the issues of (i) how global participation might be achieved, (ii) which kind of options are available to induce deep GHG reductions inside and outside the energy sector, and (iii) which risks and which co-benefits of mitigation options are not assessed by the models. [ABSTRACT FROM AUTHOR]

This study gives a synthesis of a model comparison assessing the technological feasibility and economic consequences of achieving greenhouse gas concentration targets that are sufficiently low to keep the increase in global mean temperature below 2 degrees Celsius above pre-industrial levels. All five global energy-environment-economy models show that achieving low greenhouse gas concentration targets is technically feasible and economically viable. The ranking of the importance of individual technology options is robust across models. For the lowest stabilization target (400 ppm CO2 eq), the use of bio-energy in combination with CCS plays a crucial role, and biomass potential dominates the cost of reaching this target. Without CCS or the considerable extension of renewables the 400 ppm CO2 eq target is not achievable. Across the models, estimated aggregate costs up to 2100 are below 0.8% global GDP for 550 ppm CO2 eq stabilization and below 2.5%for the 400 ppm CO2 eq pathway. [ABSTRACT FROM AUTHOR]