NBER Working Papers · 2026 · Adrien Bilal、Thibault Ingrand、Diego R. Känzig
中文摘要
本文在综合评估框架下构建了平衡增长与最优气候政策理论。尽管存在气候变化，平衡增长仍然可行，但增速会更慢。由于排放会永久提高碳存量，因此出现了两种截然不同的政策机制。当损害较低时，最优增长与自由放任情形一致，碳以恒定速率定价。当损害较高时，最优政策通过对温度增长设置上限以防止损失不断升级，并以递增速率为碳定价，从而实现比自由放任情形更快的经济增长。我们对模型进行了量化，结果表明实证损害估计涵盖了这两种机制。当损害较低时，最优政策在每世纪升温3至8°C、且长期增长率不变的条件下，实现1%的福利增益。当损害较高时，最优政策将升温上限设定为每世纪0.4°C，使年增长率提高0.8个百分点，并实现26%的福利增益。
Abstract
This paper develops a theory of balanced growth and optimal climate policy in an integrated assessment framework. Balanced growth is possible despite climate change, but at a slower rate. Two distinct policy regimes emerge because emissions permanently raise carbon stocks. For low damages, optimal growth coincides with the laissez-faire and carbon is priced at a constant rate. For high damages, optimal policy caps temperature growth to prevent escalating losses and achieve faster economic growth than in the laissez-faire by pricing carbon at an increasing rate. We quantify our model and show that empirical damage estimates span both regimes. For low damages, optimal policy achieves a 1% welfare gain with 3 to 8°C of warming per century and no change in long-run growth. For high damages, optimal policy raises annual growth by 0.8 percentage points and achieves a 26% welfare gain by capping warming at 0.4°C per century.