This paper analyses structural change in the economy as a key but largely unexplored aspect of global socio-economic and climate change mitigation scenarios. Structural change can actually drive energy and land use as much as economic growth and influence mitigation opportunities and barriers. Conversely, stringent climate policy is bound to induce specific structural and socio-economic transformations that are still insufficiently understood. We introduce Multi-Sectoral macroeconomic Integrated Assessment Models as tools to capture the key drivers of structural change and we conduct a multi-model study to assess main structural effects – changes of the sectoral composition and intensity of trade of global and regional economies – in a baseline and 2°C policy scenario by 2050. First, the range of baseline projections across models, for which we identify the main drivers, illustrates the uncertainty on future economic pathways – in emerging economies especially – and inform on plausible alternative futures with implications for energy use and emissions. Second, in all models, climate policy in the 2°C scenario imposes only a second-order impact on the economic structure at the macro-sectoral level – agriculture, manufacturing and services - compared to changes modelled in the baseline. However, this hides more radical changes for individual industries – within the energy sector especially. The study, which adopts a top-down framing of global structural change, represents a starting point to kick-start a conversation and propose a new research agenda seeking to improve understanding of the structural change effects in socio-economic and mitigation scenarios, and better inform policy assessments.

本文将经济结构变化分析为全球社会经济和气候变化减缓情景中一个关键但很大程度上尚未探索的方面。结构变化实际上可以像经济增长一样推动能源和土地使用，并影响缓解机会和障碍。相反，严格的气候政策势必会引发具体的结构和社会经济转型，而这些转型仍未得到充分理解。我们引入多部门宏观经济综合评估模型作为捕捉结构变化关键驱动因素的工具，并开展多模型研究以评估主要结构效应——全球和区域经济体的部门构成和贸易强度变化——到 2050 年的基线和 2°C 政策情景。首先，跨模型的基线预测范围，为此，我们确定了主要驱动因素，说明了未来经济路径的不确定性——尤其是在新兴经济体中——并为可能对能源使用和排放产生影响的替代未来提供信息。其次，在所有模型中，与基线模型中的变化相比，2°C 情景中的气候政策对宏观部门层面的经济结构（农业、制造业和服务业）仅产生二级影响。然而，这隐藏了个别行业更激进的变化——尤其是在能源领域。该研究采用自上而下的全球结构变化框架，是启动对话并提出新的研究议程的起点，旨在提高对社会经济和缓解情景中结构变化影响的理解，