When will warming-induced rainfall changes be perceptible?



Global climate change is not only changing temperatures but also altering precipitation. These changes in precipitation have been studied on large regional levels, but studies have not been able to identify changes in observed precipitation on smaller spatial scales. Natural interannual variability also makes it difficult to perceive precipitation changes caused by global warming at a statistically significant level. Using general circulation climate models to study future precipitation changes, Mahlstein et al. estimated how much global temperatures would need to increase for the warming-induced precipitation changes to be clearly noticeable on local or regional scales. They found that temperatures would need to be 1.4°C warmer than they were in the early twentieth century for regional precipitation changes to be statistically significant. The authors note that this is likely to occur by the end of this century. (Geophysical Research Letters, doi:10.1029/2011GL050738, 2012