Lawson Nicholas, Spears Dean
Université du Québec à Montréal, Département des sciences économiques, 320 rue Ste-Catherine Est, Bureau DS-5819, Montréal, Québec, H2X 1L7, Canada.
Department of Economics. University of Texas at Austin. 2225 Speedway. Austin, TX, USA. 78712. +1-918-493-6406.
J Popul Econ. 2018 Jan;31(1):295-335. doi: 10.1007/s00148-017-0665-9. Epub 2017 Sep 9.
A large literature considers the optimal size and growth rate of the human population, trading off the utility value of additional people with the costs of a larger population. In this literature, an important parameter is the social weight placed on population size; a standard result is that a planner with a larger weight on population chooses larger population levels and growth rates. We demonstrate that this result is conditionally overturned when an exhaustible resource constraint is introduced: if the discount rate is small enough, the optimal population today decreases with the welfare weight on population size. That is, a more total-utilitarian social planner could prefer a smaller population today than a more average-utilitarian social planner. We also present a numerical illustration applied to the case of climate change, where we show that under plausible real-world parameter values, our result matters for the direction and magnitude of optimal population policy.
大量文献探讨了人口的最优规模和增长率，权衡了新增人口的效用价值与更大人口规模带来的成本。在这些文献中，一个重要参数是赋予人口规模的社会权重；一个标准结果是，对人口赋予更大权重的规划者会选择更大的人口水平和增长率。我们证明，当引入不可再生资源约束时，这一结果会有条件地被推翻：如果贴现率足够小，当前的最优人口会随着赋予人口规模的福利权重而减少。也就是说，一个更具总量功利主义的社会规划者可能会比一个更具平均功利主义的社会规划者更倾向于选择今天有更小的人口规模。我们还给出了一个适用于气候变化情形的数值示例，表明在合理的现实世界参数值下，我们的结果对最优人口政策的方向和幅度具有重要意义。
