We develop an economic growth model that incorporates anthropogenic climate change and a publicly funded research sector that creates new technologies and simultaneously expands the productivities of existing technologies. Greenhouse gas emissions are affected by R&D activities both negatively, through the increase of output from productivity growth, and positively as new technologies are less polluting. We find that there may exist two different steady-states of the economy, depending on the amount of research spending: one with less new technologies being developed and the other with more technologies. Thus, a lock-in effect can arise that, however, can be overcome by raising R&D spending sufficiently such that the steady-state becomes unique. We derive the combinations of fiscal policy instruments for which that can be achieved and we study the implications for the economy and with respect to emissions. In particular, the double dividend hypothesis may hold under some specific conditions.

我们开发了一种经济增长模型，该模型结合了人为气候变化和由政府资助的研究部门，这些部门创造了新技术，同时扩大了现有技术的生产率。温室气体排放受到研发活动的负面影响，既受到生产力增长带来的产出增加的负面影响，也受到新技术污染较少的正面影响。我们发现，取决于研究支出的数量，经济可能存在两种不同的稳态：一种是正在研发的新技术较少，另一种是在技术较多的情况下。因此，可能会出现锁定效应，但是可以通过充分提高研发支出以使稳态变为唯一状态来克服。我们得出了可以实现的财政政策工具的组合，并且我们研究了对经济和排放的影响。特别是，双重红利假说在某些特定条件下可能成立。