23/10/2013
Credits: CC foshydog @Flickr.com

In a new study recently published on Journal of Climate, researchers E. Scoccimarro, S. Gualdi, A. Bellucci, M. Zampieri and A. Navarra from CMCC’s SERC Division investigated possible changes in the distribution of heavy precipitation events under a warmer climate, using the results of a set of 20 climate models taking part in phase 5 of Coupled Model Intercomparison Project (CMIP5). These models are the same used for the realization of the IPCC Fifth Assessment Report (AR5).
Future changes have been evaluated as the difference between the last four decades of the twenty-first century (2061-2100), and the twentieth century (1966-2005), assuming the representative concentration pathway 8.5 (RCP8.5) scenario.
The RCP8.5 is the worst IPCC scenario and corresponds to the pathway with the highest greenhouse gas emissions while combining assumptions about high population and relatively slow income growth with modest rates of technological change and energy intensity improvements, leading in the long term to high energy demand and GHG emissions in absence of climate change policies.

Results highlighted that extreme events are expected to increase in the future even more than average precipitation in the Mediterranean area, according to the RCP8.5 scenario.

The abstract of the paper:
In this work, the authors investigate possible changes in the distribution of heavy precipitation events under a warmer climate, using the results of a set of 20 climate models taking part in phase 5 of Coupled Model Intercomparison Project (CMIP5). Future changes are evaluated as the difference between the last four decades of the twenty-first century and the twentieth century, assuming the representative concentration pathway 8.5 (RCP8.5) scenario. As a measure of the width of the right tail of the precipitation distribution, the authors use the difference between the 99th and the 90th percentiles. Despite a slight tendency to underestimate the observed heavy precipitation, the considered CMIP5 models well represent the observed patterns in terms of the ensemble average, during both boreal summer and winter seasons for the 1997–2005 period. Future changes in average precipitation are consistent with previous findings based on models from phase 3 of CMIP (CMIP3). CMIP5 models show a projected increase for the end of the twenty-first century of the width of the right tail of the precipitation distribution, particularly pronounced over India, Southeast Asia, Indonesia, and central Africa during boreal summer, as well as over South America and southern Africa during boreal winter.

Read the integral version of the paper:

Scoccimarro E., Gualdi S., Bellucci A., Zampieri M., Navarra A. 

Heavy precipitation events in a warmer climate: results from CMIP5 models
2013, Journal of Climate, 26, 7902–7911, DOI: http://dx.doi.org/10.1175/JCLI-D-12-00850.1