Endogenous Technological Change in the DICE Model of Global Warming

在考虑气候变化等长期环境问题的解决方案时，重要的是要考虑技术变革可能发挥的作用。 尽管如此，大多数气候变化经济模型都将技术视为外生的。 由于应对气候变化所采取的政策可能会对技术变革的步伐和方向产生重大影响，因此这些模型忽略了政策与创新之间的重要联系。 拟议的项目通过利用能源行业技术变革的实证结果，将内生技术变革纳入气候变化的DICE模型来解决这一问题。迄今为止，很少有气候变化模型包含影响碳排放的内生技术变革。 尽管这些模型为内生技术变革建模做出了宝贵的贡献，但它们缺乏对技术变革本质的实证估计。 因此，本研究最重要的贡献在于，它利用能源部门技术变革的实证研究来更准确地模拟可能有助于改善气候变化的技术变化。本研究将首先修改气候变化的DICE模型，以与现有实证研究一致的方式纳入内生技术变化。此外，通过利用 DICE 模型（该模型明确模拟了温室气体减排的成本和收益），本研究旨在更好地理解内生技术变革的考虑如何影响最优政策决策。 人们可以想象两种抵消效应。 首先，可能需要征收更高的碳税，因为税收会导致研发增加，从而降低实现给定减排水平的成本。 其次，可能需要较低的碳税，因为税收带来的创新可以更容易地实现给定的减排目标。 修订后的 DICE 模型将用于研究这两种效应中哪一种占主导地位。最后，拟议的研究通过模拟逆止技术研究对提取可耗尽化石燃料供应的影响，扩展了该领域其他研究人员的先前工作。 该项目特别询问加速非碳支撑技术进步的政策是否也会提高化石燃料储量的开采速度。

When considering solutions to long-term environmental problems such as climate change, it is important to consider the role that technological change may play. Nonetheless, most economic models of climate change treat technology as exogenous. Since policies adopted to combat climate change are likely to have a large impact on the pace and direction of technological change, these models miss the important link between policy and innovation. The proposed project addresses this concern by making use of empirical results on technological change in the energy industry to incorporate endogenous technological change into the DICE model of climate change.To date, few models of climate change include endogenous technological change that affects carbon emissions. Although these models offer valuable contributions to the efforts of modeling endogenous technological change, they suffer from a lack of empirical estimates on the nature of technological change. Thus, the most important contribution of the proposed research is that it makes use of empirical studies of technological change in the energy sector to more accurately model technological change that may help ameliorate climate change.The proposed research will begin by modifying the DICE model of climate change to include endogenous technological change in a manner consistent with existing empirical studies. In addition, by making use of the DICE model, which explicitly models both the costs and benefits of greenhouse gas reduction, the proposed research aims to provide a better understanding of how consideration of endogenous technological change affects the optimal policy decision. One can imagine two offsetting effects. First, a higher carbon tax may be desired, because the tax leads to increased R&D, which lowers the cost of achieving a given level of abatement. Second, a lower carbon tax may be desired, because the innovation induced by a tax allows a given abatement target to be achieved more easily. The revised DICE model will be used to study which of these two effects dominates.Finally, the proposed research extends previous work of other researchers in this area by modeling the effect of research on a backstop technology on the extraction of an exhaustible supply of fossil fuels. In particular, the project asks whether policies that speed up technological advances in non-carbon backstop technologies also increase the rate at which the stock of fossil fuels is extracted.