About 78% of global greenhouse gas emissions between 1970 and 2010 were due to fossil fuel combustion, increasing the atmospheric mixing ratio of carbon dioxide to around 419 ppm by June 2021. During a similar period, between 1975 and 2017, 162 countries adopted renewable energy targets – official national commitments to increase the share of renewable energies. What induced the diffusion of these renewable energy targets? What are the patterns of their diffusion? We analyze data from 187 countries and assess four possible mechanisms of policy diffusion of renewable energy targets: learning, economic competition, emulation, and coercion. Using a qualitative comparative analysis, we find eight pathways to renewable energy target adoption. In the most common pathways, economic competition, emulation, and coercion played a significant role. Before there is a critical mass of countries to emulate, our analysis shows that early adopters followed the mechanisms of economic competition and coercion. Ultimately, we find that there is no one recipe for the diffusion of renewable energy targets, and we identify the specific countries associated with the different diffusion pathways.

1970 年至 2010 年间，全球约 78% 的温室气体排放来自化石燃料燃烧，到 2021 年 6 月，二氧化碳在大气中的混合比例增加至 419 ppm 左右。在同一时期，1975 年至 2017 年间，162 个国家采用了可再生能源目标——增加可再生能源份额的国家官方承诺。是什么促使这些可再生能源目标的扩散？它们的传播模式是什么？我们分析了 187 个国家的数据，并评估了可再生能源目标政策扩散的四种可能机制：学习、经济竞争、模仿和胁迫。通过定性比较分析，我们发现了采用可再生能源目标的八种途径。在最常见的途径中，经济竞争、模仿和胁迫发挥了重要作用。在有大量国家可以效仿之前，我们的分析表明，早期采用者遵循的是经济竞争和强制机制。最终，我们发现可再生能源目标的传播没有一种方法，我们确定了与不同传播途径相关的特定国家。