Environmental Policy and the Direction of Technical Change
研究政府是否应将研发从“肮脏”技术转向“清洁”技术，以及碳定价的重要性，发现政府应优先支持清洁研发，因为清洁技术的私人与社会价值差距更大。
Abstract Should governments direct research and development (R&D) away from “dirty” technologies towards “clean” ones? How important is this compared to carbon pricing? We address these questions with the introduction of two model features to the literature on directed technological change and the environment. We introduce decreasing returns to R&D, and allow future carbon taxes to influence current R&D decisions. Our results suggest that governments should prioritize clean R&D. Dealing with major environmental problems requires an R&D shift towards clean technology. However, in the case where most researchers are working with clean technology, both productivity spillovers and the risks of future replacement increase. Consequently, the gap between the private and social values of an innovation is greatest for clean technologies.