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，大多数气候变化的经济模型都将技术视为外源性的。由于为应对气候变化而采取的政策可能会对技术变革的速度和方向产生重大影响，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DICE模型来解决这一问题。迄今为止，很少有气候变化模型包括影响碳排放的内源性技术变化。尽管这些模型为内生技术变革建模的努力提供了宝贵的贡献，但它们缺乏对技术变革本质的经验估计。因此，所提出的研究最重要的贡献是，它利用能源部门技术变革的实证研究，更准确地模拟可能有助于缓解气候变化的技术变革。拟议的研究将首先修改DICE气候变化模型，以符合现有实证研究的方式纳入内生技术变化。此外，本文还利用DICE模型对温室气体减排的成本和收益进行了明确的建模，旨在更好地理解考虑内生技术变革如何影响最优政策决策。人们可以想象两种相互抵消的影响。首先，人们可能希望征收更高的碳税，因为碳税会导致研发增加，从而降低达到既定减排水平的成本。其次，低碳税可能是可取的，因为税收引发的创新使既定的减排目标更容易实现。修正后的DICE模型将用于研究这两种影响中哪一种占主导地位。最后，拟议的研究扩展了其他研究人员在这一领域的先前工作，通过模拟研究对提取可耗尽的化石燃料供应的支持技术的影响。该项目特别提出了一个问题，即加速非碳支持技术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.