Notably, the multi-model median change in precipitation is relatively small in many regions-less than 10% over most of the global land surface at 1.5°C global warming. In contrast, in many locations, the 5th to 95th percentile range can include changes that are much larger changes than the median and also changes that are relatively large but opposite in sign. At 4ºC global warming, the median projected changes are larger, ranging from a 20% decrease to a 40% increase , but nevertheless often remain a poor indicator of the range of changes across the ensemble. Therefore, use of the median or mean projected changes for future adaptation decisions could substantially underestimate the risk of large changes in precipitation. It could mean that the risk of the opposite sign of changes is not accounted for. Indeed, for mean precipitation, different multi- model ensembles can show different levels of significance of the central estimate of change . Consequently, information on the range of possible outcomes can be valued by users for effectively informing risk assessments .
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report