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办法时，必须考虑到技术变革可能发挥的作用。 然而，大多数气候变化经济模型都将技术视为外生的。 由于为应对气候变化而采取的政策可能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。 本研究利用能源产业技术变化的实证结果，将内生性技术变化纳入DICE气候变化模型，解决了这一问题。迄今为止，在气候变化模型中，很少有包含影响碳排放的内生性技术变化的模型。 虽然这些模型提供了宝贵的贡献的努力，模拟内生技术变革，他们遭受缺乏经验估计的技术变革的性质。 因此，本研究最重要的贡献在于，利用能源领域的技术变化的实证研究，更准确地模拟有助于改善气候变化的技术变化。本研究开始，将与现有实证研究一致的方式，对DICE气候变化模型进行修正，使其包含内生性技术变化。此外，通过使用DICE模型，明确模拟温室气体减排的成本和收益，拟议的研究旨在提供一个更好的理解如何考虑内生技术变化影响最优政策决策。 我们可以想象两种抵消效应。 首先，可能需要征收更高的碳税，因为碳税会导致研发活动的增加，从而降低实现特定减排水平的成本。 第二，较低的碳税可能是可取的，因为税收引发的创新使特定的减排目标更容易实现。 修订后的DICE模型将被用来研究这两种影响占主导地位。最后，拟议的研究扩展了以前的工作，在这一领域的其他研究人员通过建模的影响，研究的支持技术的提取可耗尽的化石燃料供应。 特别是，该项目提出的问题是，加快非碳支持技术进步的政策是否也会增加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.