Emission implications of long-term climate targets

摘要: This paper presents a set of multi-gas emission pathways compatible with different levels of ambition of avoiding long-term climate change, expressed in terms of long-term temperature targets, such as the EU 2oC target, and the certainty of achieving these. Also the effect of different assumptions on the resulting emission pathways, such as different baselines, technological improvement rates, or delay of global action is analysed. For achieving the EU target with a certainty of more than 50%, greenhouse gas concentrations need to be stabilised at 450 CO2 equivalent or lower, requiring global emissions to peak within the next two decades, followed by substantial overall reductions by as much as 30 to 50% in 2050 compared to 1990 levels. The total emission reductions and the abatement costs strongly depend on the emissions growth in the baseline scenario and the further improvements of the abatement potential and reduction costs for all greenhouse gases in the future.