Next year in Paris, parties to the UN Framework Convention on Climate Change have the task of developing a global agreement to reduce carbon emissions — a successor to the failed Kyoto Protocol. They should strike a grand bargain with the World Trade Organization (WTO) to promote green industry.

For example, the new protocol could draw up an open-ended list of products and processes that would reduce emissions. This could then be used to exempt countries from the rules of fair trade for, say, five years, to allow them to build green industries.

Trade in green industries is crucial for transforming fossil-fuelled economies. Countries trying to promote a green economy should not have to experience trade disputes (see, for instance, go.nature.com/7joyyk).

There is a precedent for such exemptions in the WTO's General Agreement on Tariffs and Trade. The negotiation of a new 'Paris Protocol' provides a once-in-a-generation chance to create green industries and to cut emissions.