Study shows how climate change affects rain and floods

Washington DC [US], March 14 (ANI): Climate change may lead to more precipitation and more intense floods. A new study shows that to understand the details of this relationship, it is important to distinguish between different types of rainfall and flood events -- namely, between short-term events that occur on a time scale of hours, and longer-term events that last several days. In each case, climate change has a different impact.
An Austrian research team has now shown for the first time that short-term precipitation and flood events on the scale of a few hours are particularly affected by the temperature increase caused by climate change.
For events on a longer time scale, the relationship is more complicated. This finding was made using detailed data collected in Austria over more than a century -- but it can also be applied to other regions of the world.
It also allows conclusions to be drawn about which regions will experience changes in the probability of flooding, and how they will be affected. The results have now been published in the journal Nature.
Climate change is affecting water cycles all over the world. A look at Austria is particularly revealing: "We are in the very fortunate situation of having excellent data available," says Prof. Gunter Bloschl of TU Wien (Vienna), who led the research project. Since 1900, precipitation in Austria has been recorded by two separate institutions: by the meteorological service, now Geosphere Austria, and by the Austrian Hydrography, which is managed by the Ministry of Agriculture.
The Austrian data are therefore particularly reliable and can be used to make forecasts for other countries.
These data sets have now been analysed in a cooperation of TU Wien, the Federal Ministry of Agriculture, Forestry, Environment and Water Management (BML), GeoSphere Austria and the University of Graz.
The analysis showed that short-term precipitation events lasting only a few hours have increased significantly in the last 30-40 years -- by about 15%. "This had already been predicted by climate models, albeit with uncertainties. We have now been able to confirm it," says Gunter Bloschl.
However, if longer-term rainfall events lasting several days are analyzed, a different picture emerges. In that case, global weather phenomena such as El Nino, a climate process influenced by ocean temperatures, play a much more decisive role. Rainfall events on this timescale are therefore not changing everywhere in the same way.
In the Mediterranean, in some regions of Italy, Spain and Greece, long periods of precipitation may even become rarer as a result of climate change. (ANI)