Directed Technical Change as a Response to Natural Resource Scarcity
构建了一个量化宏观经济理论，分析市场如何通过节约投入的技术变革来应对自然资源稀缺，并以化石燃料为例。研究发现，美国数据表明能源与资本/劳动之间的短期替代弹性很低，而1970年代石油危机后能源节约型技术变革显著加速，长期内实现了与其他投入的有效替代，即使在能源价格持续上涨的情况下，长期消费增长仍有可能。
We develop a quantitative macroeconomic theory of input-saving technical change to analyze how markets economize on scarce natural resources, with an application to fossil fuel. We find that aggregate US data call for a very low short-run substitution elasticity between energy and the capital/labor inputs. Our estimates imply that energy-saving technical change took off when the oil shocks hit in the 1970s. This response implies significant substitutability with the other inputs in the long run: even under ever-rising energy prices, long-run consumption growth is still possible, along with a modest factor share of energy.