The Intensification of Global and Regional Climate Variability and Change

Recent evidence from the IPCC and National Climate Assessment reports indicate that extreme climate events are increasing in many regions of the world. Interestingly, the nature and causes of the changes in extremes may be expressed differently for the global and regional scales, and also amongst climate variables (e.g., precipitation and temperature). For instance, over the last several decades the temperature probability density function on the global scale exhibits a mean shift to the warmer side, as opposed to a change in it's variability. Conversely, the interannual variability of precipitation is intensifying on the regional scale, especially over the U.S. during spring. Although the statistical characteristics of the temperature and precipitation changes may have a varied expression they both contribute to the potential for increases in extreme events. The causes and physical mechanisms for the intensification of mean global temperature and regional precipitation variability are explored using observationally constrained datasets and non-traditional climate model approaches.