Climate change is one of the most serious threats to the human habitat. The required structural change to limit anthropogenic forcing is expected to fundamentally change daily social and economic life. The production of iron and steel is a special case of economic activities since it is not only associated with combustion but particularly with process emissions of greenhouse gases which have to be dealt with likewise. Traditional mitigation options of the sector like efficiency measures, substitution with less emission-intensive materials, or scrap-based production are bounded and thus insufficient for rapid decarbonization necessary for complying with long-term climate policy targets. Iron and steel products are basic materials at the core of modern socio-economic systems, additionally being essential also for other mitigation options like hydro and wind power. Therefore, a system-wide assessment of recent technological developments enabling almost complete decarbonization of the sector is substantially relevant. Deploying a recursive-dynamic multi-region multi-sector computable general equilibrium approach, we investigate switches from coke-to hydrogen-based iron and steel technologies in a scenario framework where industry decisions (technological choice and timing) and climate policies are misaligned. Overall, we find that the costs of industry transition are moderate, but still ones that may represent a barrier for implementation because the generation deciding on low-carbon technologies and bearing (macro)economic costs might not be the generation benefitting from it. Our macroeconomic assessment further indicates that anticipated bottom-up estimates of required additional domestic renewable electricity tend to be overestimated. Relative price changes in the economy induce electricity substitution effects and trigger increased electricity imports. Sectoral carbon leakage is an imminent risk and calls for aligned course of action of private and public actors.

气候变化是对人类栖息地最严重的威胁之一。为限制人为强迫而进行的必要结构性改变有望从根本上改变日常的社会和经济生活。钢铁生产是经济活动的一种特殊情况，因为它不仅与燃烧有关，而且特别与必须同样处理的温室气体的过程排放有关。该行业的传统减缓方案，例如效率措施，用排放量较少的材料替代或废料生产，是有局限性的，因此不足以满足长期气候政策目标所需的快速脱碳。钢铁产品是现代社会经济体系的核心基础材料，此外，对于其他缓解措施（例如水力和风力发电）也必不可少。因此，对使该行业几乎完全脱碳的最新技术发展进行全系统评估非常重要。部署递归动态多区域多部门可计算的一般均衡方法，我们研究了在行业决策（技术选择和时间安排）与气候政策不一致的情况下从焦炭到氢基钢铁技术的转换。总体而言，我们发现产业转型的成本是适度的，但仍然可能成为实施的障碍，因为决定低碳技术和负担（宏观）经济成本的一代可能不会从中受益。我们的宏观经济评估进一步表明，对所需的额外国内可再生电力的自下而上的估计往往被高估了。经济中的相对价格变化会引起电力替代效应并引发电力进口增加。部门碳泄漏是迫在眉睫的风险，需要私人和公共行为者采取一致的行动方针。