In recent years, many governments have implemented environmental regulations to combat climate change. In particular, carbon taxes have shown to be an important policy tool to reduce emissions. However, there is little clarity about what drives this relationship. Based on the Porter hypothesis, we find evidence of innovation as a mediator between carbon taxes and CO emissions. Using Canadian province-level data from the period 1997–2015, we exploit the implementation of the 2008 British Columbian carbon tax to conduct a difference-in-differences analysis. Our results suggest a statistically and economically significant switch from product innovation to process innovation for British Columbia compared to other Canadian provinces not subject to the carbon tax. So, the stimulating impact of carbon taxes on process innovation appears to be an important explanation for the reduction of emissions.

中文翻译：

---

环境税对创新的影响：来自加拿大的证据

近年来，许多政府都实施了环境法规来应对气候变化。特别是，碳税已被证明是减少排放的重要政策工具。然而，目前尚不清楚是什么推动了这种关系。基于波特假说，我们发现创新作为碳税和二氧化碳排放之间中介的证据。我们利用 1997 年至 2015 年期间加拿大省级数据，利用 2008 年不列颠哥伦比亚省碳税的实施情况进行双重差分分析。我们的研究结果表明，与加拿大其他不受碳税影响的省份相比，不列颠哥伦比亚省从统计和经济上都实现了从产品创新到流程创新的重大转变。因此，碳税对工艺创新的刺激作用似乎是减排的一个重要解释。