Domestic emission trading schemes are brought to attention as an administrative method for reducing greenhouse gas emissions in a flexible and effective manner, and now various countries and regions are developing those schemes. To deepen our understanding of the current situation and the challenges for combating global warming, IGES held an open symposium "Emerging Domestic/Regional Emissions Trading Systems: Challenges and Prospects." In the symposium, experts and administrators from the USA, Europe and Japan reported on initiatives being taken in the country and region, and specialists from around the world presented on the future prospects for emissions trading in the panel discussion.