It was in the 1990s that aspects of energy and climate research began to merge at IIASA, as the implications of the IPCC's first and second assessment reports on climate change, with their implications for energy use, took hold.
The economics of climate change were studied in depth at IIASA, and ECS developed an inventory of more than 1,500 energy and emissions mitigation technologies. Energy scientists made leading contributions to the Special Report on Emissions Scenarios (SRES) and Second and Third Assessment Reports of the IPCC, as well as the World Energy Assessment.
A number of policy-oriented energy scenarios, including a joint book with the World Energy Council on Global Energy Perspectives,were published in 1998. In the same year studies on the dynamics of energy technologies were released, including a major book on Technology and Global Change. The latter publication indicated the emerging importance of new technology as a means to mitigate climate change and to help the world transition to cleaner energy use.