The climate targets agreed in Paris 2015 render deep decarbonization of energy- and emission-intensive industries crucial. Policy makers are interested in the macroeconomic consequences of such decarbonization pathways and often rely on integrated modelling studies. However, the underlying modelling assumptions and uncertainties often remain unquestioned or invisible, although they may govern the models' results. For the case of a zero-process emission pathway of the European iron and steel industry, we demonstrate how different assumptions on different “layers” of uncertainty influence results. We show that effects strongly depend on technology choice, prevailing macroeconomic states as well as regional characteristics. The underlying socio-economic development and the climate policy trajectory seem to play a less important role. Particularly, we find that the choice of model, i.e. which macroeconomic theory strand it arises from, influences the sign and magnitude of macroeconomic effects and thus should be well understood in terms of appropriate interpretations by both modelers and policy makers. We emphasize that model assumptions should be transparent, results sought as to be robust across a range of possible contexts, and presented together with the conditions under which they are valid. To that end, co-design and co-production in research would support its relevance and applicability.

中文翻译：

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低碳转型路径宏观经济评估的不确定性——以欧洲钢铁行业为例

2015 年在巴黎达成的气候目标使能源和排放密集型行业的深度脱碳变得至关重要。政策制定者对这种脱碳途径的宏观经济后果很感兴趣，并且通常依赖于综合模型研究。然而，潜在的建模假设和不确定性通常不会受到质疑或不可见，尽管它们可能会影响模型的结果。对于欧洲钢铁行业零过程排放路径的案例，我们展示了对不同“层”不确定性的不同假设如何影响结果。我们表明，影响在很大程度上取决于技术选择、流行的宏观经济状态以及区域特征。潜在的社会经济发展和气候政策轨迹似乎不太重要。特别，我们发现模型的选择，即它来自哪个宏观经济理论分支，会影响宏观经济效应的符号和大小，因此建模者和政策制定者都应该通过适当的解释来很好地理解。我们强调模型假设应该是透明的，结果应该在一系列可能的背景下保持稳健，并与它们有效的条件一起呈现。为此，研究中的联合设计和联合生产将支持其相关性和适用性。我们强调模型假设应该是透明的，结果应该在一系列可能的背景下保持稳健，并与它们有效的条件一起呈现。为此，研究中的联合设计和联合生产将支持其相关性和适用性。我们强调模型假设应该是透明的，结果应该在一系列可能的背景下保持稳健，并与它们有效的条件一起呈现。为此，研究中的联合设计和联合生产将支持其相关性和适用性。