UNEP CO2 Uncertainty - Reports

<b>Quantifying uncertainty in baseline projections of carbon dioxide emissions for South Africa</b><br><br> 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. <br><br> 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.<b>南非二氧化碳排放基线预测中的不确定性量化</b><br><br>本项目旨在量化关键模型输入相关的不确定性，从而构建2015-2050年期间南非排放基线的概率分布。该目标将通过两个阶段实现：第一阶段，筛选出不确定性分析中最重要且具有不确定性的输入参数，并对相关不确定性进行描述；第二阶段，通过南非的E3模型（南非TIMES模型，South African TIMES Model，简称SATIM）传播输入不确定性，以获取研究期间南非排放基线的概率分布。<br><br>对如此长远的未来进行预测是一项极其复杂——甚至可能是难以完成的任务。为此，我们结合多种方法学路径，通过方法间的三角验证，力求得出具有共识性的预测结果。本研究采用的路径是：评估影响能源系统及相关温室气体（Greenhouse Gas, GHG）排放的少数关键驱动因素的不确定性；确定这些驱动因素未来可能取值的分布，并将其输入E3模型；模型针对每组可能的输入，返回GHG排放等变量的输出结果。通过向SATIM输入大量可能的参数组合，可得到一系列潜在输出，此过程采用蒙特卡洛模拟（Monte Carlo simulation）形式。本研究由联合国环境规划署（United Nations Environment Programme）委托开展。