The IPCC scenario stories and numerical projections remain based on what was known in the second half of the 1990s. The stories were used to build the emissions scenarios for IPCC’s Third Assessment Report (2001), which were then reviewed in the Fourth Assessment Report (AR4) in 2007. While it was acknowledged then that the threat of climate change had intensified, the scenario stories were not updated, and emissions scenarios published since 2000 were found to be reasonably comparable with the original projections. New scientific evidence since the writing of AR4 strongly suggests that climate change is accelerating, and the emissions scenarios are getting outdated as described in a background paper for the main Climate Change and the Florida Keys report. The findings provided a basis for a critical review of the original scenarios in the main project report. These updates must suffice until IPCC publishes new scenarios for its Fifth Assessment Report, due in 2013.