Don't look now but we are running in midair, a new book asserts. In 2052: A Global Forecast for the Next Forty Years (Chelsea Green Publishing), Jorgen Randers of the BI Norwegian Business School in Oslo, and one of the original World3 modelers, argues that the second half of the 21st century will bring us near apocalypse in the form of severe global warming. Dennis Meadows, professor emeritus of systems policy at the University of New Hampshire who headed the original M.I.T. team and revisited World3 in 1994 and 2004, has an even darker view. The 1970s program had yielded a variety of scenarios, in some of which humanity manages to control production and population to live within planetary limits (described as Limits to Growth). Meadows contends that the model's sustainable pathways are no longer within reach because humanity has failed to act accordingly.
Graham Turner of Australia's Commonwealth Scientific and Industrial Research Organization fears that collapse could come even earlier, but due to peak oil rather than climate change. After comparing the various scenarios generated by World3 against recent data on population, industrial output and other variables, Turner and, separately, the PBL Netherlands Environmental Assessment Agency, conclude that the global system is closely following a business-as-usual output curve. In this model run the economy continues to grow as expected until about 2015, but then falters because nonrenewable resources such as oil become ever more expensive to extract.