An international study, which includes the State University of Milan, based on data of 23 thousand stations in twenty -seven countries, analyzes the trend of rainfall in the Mediterranean since 1871. The research, published on “NATURE”, Confirms the historical stability of the rains but provides for a significant drop in the 21st century
A study of global relevance
An international team of researchers, led by Sergio Vicente Serrano del Pyrenean Institute of EcologySpain, and Yves Tramblay of the French Institute of Research for DevelopmentMarseille, conducted a global relevance study. The research, enriched by the contribution of the State University of Milan, the University of Salento and the CNR-ISACanalyzed the trend of rainfall in the Mediterranean from 1871 to 2020.
The results show that although the distribution was irregular, the overall amount of rain has remained substantially stable. However, in the 21st century, the projections indicate a significant drop in rainfall.
“This agreement between the modeling simulations and the observations on the stability of rainfall in the past strengthens the reliability of the forecasts of a future reduction of rains”says Maurizio Maugeri, professor of Department of environmental sciences and policies of the State University of Milan.
An innovative method of analysis
Posted on Naturethe study is based on data collected by 23 thousand weather stations in twenty -seven countries. The research fills a cognitive gap caused by the poor sharing of the observational series of the past, due to restrictive policies of some Mediterranean nations.
To overcome this limitation, the researchers have developed an innovative method of analysis that allowed data processing in distributed, using a single package of codes without the need to share the raw data between the countries involved.
Concerns about the future
The survey confirms that, in the long run, the rains in the region showed high spatial and temporal variability, without however suffering substantial variations. The trends identified for some areas and temporal intervals are connected to the natural internal climatic variability.
“This reduction is very worrying – continues the teacher – Because the Mediterranean region is already going through a period of growing climatic aridity, caused by the increase in evaporation due to the strong increase in temperatures “.
In addition, the most recent simulations of the Cmip 6 international project are confirmed in the observations collected. This strengthens the reliability of the forecast models and supports the projections of a future reduction in rainfall in the Mediterranean area.
“We fear, therefore, that in the next decades the scarcity of water resources and the aridity in the region will be aggravated”concludes Maugeri, among the first signatories of the study together with Professor Piero Lionello del Department of biological and environmental sciences and technologies of the University of Salento.