Uncertainties in the timing of unprecedented climates

Arising from C. Mora et al. Nature502, 183–187 (2013) The question of when the signal of climate change will emerge from the background noise of climate variability—the ‘time of emergence’—is potentially important for adaptation planning. Mora et al. 1 presented precise projections of the time of emergence of unprecedented regional climates. However, their methodology produces artificially early dates at which specific regions will permanently experience unprecedented climates and artificially low uncertainty in those dates everywhere. This overconfidence could impair the effectiveness of climate risk management decisions 2 . There is a Reply to this Brief Communication Arising by Mora, C. et al . Nature 511, http://dx.doi.org/10.1038/nature13524 (2014).