Global precipitation variability decreased from 1940 to 2009


  • Colin Schultz


One of the strongly held assumptions of climate change is that the variability of precipitation will grow with an increase in temperature. Storms will become heavier but less frequent. Flash floods and droughts will increase. Regions that see extensive rainfall will get even more while arid regions will dry out. These projections stem from the way temperature affects precipitation patterns in global models. However, drawing on seven databases representing global monthly mean precipitation values, Sun et al. found that from 1940 to 2009 global overland precipitation variability actually decreased. In addition, they found that the changes in precipitation patterns that did occur led to a redistribution of rainfall such that on average wet areas and seasons got drier, and dry areas and seasons got wetter.