"This paper develops a simple model of a polluting industry and an innovating firm. The polluting industry is faced with regulation and costly abatement. Regulation may be taxes or marketable permits. The innovating firm invests in R&D and develops technologies which reduce the cost of pollution...

"Public policies for pollution control, including climate change policies, sometimes allow polluters in one sector subject to an emissions cap to offset excessive emissions in that sector with pollution abatement in another sector. The government may often find it more costly to verify offset...