The Global Scenario Group (GSG) was an international, interdisciplinary body convened in 1995 by the Tellus Institute and the Stockholm Environment Institute (SEI) to develop scenarios for world development in the twenty-first century. Further development of the Great Transition scenarios has been carried on by the Great Transition Initiative (GTI).
The GSG's underlying scenario development work was rooted in the long-range integrated scenario analysis that Tellus Institute and Stockholm Environment Institute had undertaken through the PoleStar Project and its PoleStar System. Initially conceived in 1991 as a tool for integrated sustainability planning and long-range scenario analysis, the PoleStar System was inspired by the 1987 Brundtland Commission report Our Common Future, which first put the concept of sustainable development on the international agenda.
The work of the Global Scenario Group was widely adopted in high-level intergovernmental settings. The scenarios informed numerous international assessments, including the World Water Council's World Water Vision report in 1999–2000, the OECD Environmental Outlook in 2001, the Intergovernmental Panel on Climate Change's greenhouse gas emission mitigation assessment in 2001, the United Nations Environment Programme's Third GEO Report in 2002, and the Millennium Ecosystem Assessment in 2005.
Several of the GSG participants who actively participated in the IPCC assessments have been recognized for contributing to the 2007 award of the Nobel Peace Prize to the IPCC.
In 2002, the GSG formally summarized their scenario approach in an essay called Great Transition: The Promise and Lure of the Times Ahead.