UNEP CO2 Uncertainty - Dissemination

Quantifying uncertainty in baseline projections of carbon dioxide emissions for South Africa The objective of this project is to quantify the uncertainty associated with key model inputs to develop a probability distribution of baseline emissions for South Africa over the 2015-2050 period. This objective is to be met in two phases. In the first phase, the most important and uncertain input parameters were selected for uncertainty analysis, and the associated uncertainty was described. In the second phase the uncertainty in inputs is propagated via an E3 model of South Africa (South African TIMES Model - SATIM) to obtain the probability distribution for the baseline emissions of South Africa, over the period of interest. Projecting this far into the future is an extremely, perhaps impossibly, complex task. We use a combination of methodological approaches to do this, triangulating between these approach in an attempt to arrive at some kind of consensus projections. The approach followed here is to assess uncertainty on a small number of key drivers influencing the energy system, and hence GHG emissions associated with it. We assess distributions over possible values that these drivers can obtain in the future, and pass these values to the E3 model. For each combination of possible inputs, the model returns outputs for quantities like GHG emissions. By submitting many possible inputs to SATIM, a range of possible outputs is obtained. This process takes the form of a Monte Carlo simulation. This study was commissioned by the United Nations Environment Programme.

南非二氧化碳排放基线预测的不确定性量化
本项目旨在量化关键模型输入参数的不确定性，以构建2015-2050年南非基线碳排放的概率分布。本项目将通过两个阶段达成该目标。第一阶段，遴选对不确定性分析最为关键且不确定性较高的输入参数，并对其相关不确定性进行描述。第二阶段，通过南非能源-经济-环境（Energy-Economy-Environment, E3）模型——南非TIMES模型（SATIM），将输入端的不确定性进行传播，从而得到目标时段内南非基线碳排放的概率分布。
对如此遥远的未来进行排放预测是一项极为复杂、甚至近乎难以完成的任务。本研究结合多种方法论路径，通过对这些方法进行三角互证，以期形成具备一定共识的预测结果。
本研究采用的方法为：针对影响能源系统进而关联温室气体（Greenhouse Gas, GHG）排放的少数关键驱动因子评估其不确定性，先确定这些驱动因子未来可能取值的分布，再将这些取值输入至E3模型中。针对每一组可能的输入组合，模型将输出温室气体排放量等相关量化指标的结果。通过向SATIM模型输入大量可能的参数组合，即可得到一系列潜在的输出结果，该过程采用蒙特卡洛模拟（Monte Carlo Simulation）实现。
本研究由联合国环境规划署（United Nations Environment Programme, UNEP）委托开展。