Department of Agricultural and Consumer Economics, University of Illinois at Urbana-Champaign, Urbana, IL 61801;
School of Forestry & Environmental Studies, Yale University, New Haven, CT 06511.
Proc Natl Acad Sci U S A. 2018 May 22;115(21):5409-5414. doi: 10.1073/pnas.1713628115. Epub 2018 May 14.
Forecasts of long-run economic growth are critical inputs into policy decisions being made today on the economy and the environment. Despite its importance, there is a sparse literature on long-run forecasts of economic growth and the uncertainty in such forecasts. This study presents comprehensive probabilistic long-run projections of global and regional per-capita economic growth rates, comparing estimates from an expert survey and a low-frequency econometric approach. Our primary results suggest a median 2010-2100 global growth rate in per-capita gross domestic product of 2.1% per year, with a standard deviation (SD) of 1.1 percentage points, indicating substantially higher uncertainty than is implied in existing forecasts. The larger range of growth rates implies a greater likelihood of extreme climate change outcomes than is currently assumed and has important implications for social insurance programs in the United States.
长期经济增长预测是当前经济和环境政策决策的关键输入。尽管其重要性不言而喻，但关于长期经济增长预测及其不确定性的文献却很少。本研究提供了全球和地区人均经济增长率的综合概率长期预测，比较了专家调查和低频计量经济学方法的估计结果。我们的主要结果表明，2010 年至 2100 年期间全球人均国内生产总值的年增长率中位数为 2.1%，标准差（SD）为 1.1 个百分点，表明不确定性远高于现有预测所暗示的水平。更大的增长率范围意味着比当前假设更有可能出现极端气候变化结果，这对美国的社会保险计划有重要影响。
