It is very hard to make much of a dent in the problem of global climate change without inventing and deploying new, radically different technologies. Most emissions of warming gases come from industrial energy systems that will be expensive and difficult to alter until new technologies appear. In the electric power sector, for example, deep cuts in emissions are feasible with massive deployment of new renewable energy supplies or thousands of new commercial-scale nuclear reactors, among many other options. Yet today's intermittent renewable energy supply options are impractical at a large scale without new systems for storing power and assuring stability of the power grid. Expanding today's worldwide fleet of 436 nuclear reactors to perhaps 1,500 or 2,000 reactors will probably require wholly new reactor designs as well as new systems for supplying fissile fuel that are more frugal and less prone to proliferate nuclear weapons. Huge leverage on emissions probably will require rethinking the whole energy system.

This chapter is about policies that could spur invention and use of those technologies – what I will call “technology policy.” The pace of serious efforts to control warming emissions will depend, in part, on success with technology policy. I will focus on energy, which accounts for most warming gases, although big innovations may also play a role in agriculture, forestry, and other activities that also cause substantial emissions. About five-sixths of all CO2 and a large portion of other warming cases originate in the energy system.