International environmental policy discussions occur between these points. There is knowledge, at least in some quarters, that a potential problem exists. But significant uncertainties regarding the severity, causal links, impact and time frame the problem. If there are large levels of scientific uncertainty, as there were in the ozone negotiations between 1977 and 1985, the debate is likely to take place within a range near the left extreme of our imaginary line. Increasing knowledge will likely shift the debate toward more forceful policy options.
Nothing is determined by increasing scientific knowledge per se.
It simply becomes more difficult to advocate no policy response. This process occurred in the ozone negotiations. Each major period in the negotiations was immediately preceded by, or took place in tandem with, large-scale scientific assessments organized by regime institutions, including, after 1985, the well respected Scientific Assessment Panel process. In the most notable examples, the 1996 report by the Scientific Assessment Panel helped to stretch the bargaining range during the 1986-1987 negotiations on the original Montreal Protocol, providing greater leverage for control proponents. The 1989 Assessments stated clearly that seasonal ozone depletion had occurred not only over Antarctica but also above the northern hemisphere and that releases of manmade ODS were most probably responsible.