Floods are impacted by a changing climate

August 28, 2019

Climate change affects not only the temporal pattern of floods, but also their magnitude. This is shown by an international study which evaluated data from more than 3,700 flood monitoring stations throughout Europe over a period of 50 years. According to the data, flood events are increasing in northwestern Europe and decreasing in southeastern Europe. The study, in which Bruno Merz of GFZ German Research Centre for Geosciences was also involved, appears in the journal Nature.

Rivers overflowing their banks cause around 100 billion dollars of damage worldwide every year. And researchers have long suspected that climate change could exacerbate the problem. But there was a lack of data. "Two years ago, we were able to show that temporal patterns are changing. Now, together with international colleagues, we have demonstrated that the severity of events is also influenced by climate change," says Bruno Merz, head of the Hydrology Section at GFZ. He was involved in the study, which was led by Günter Blöschl from Vienna. Blöschl, who conducts research at the Vienna University of Technology, was a member of the Scientific Advisory Board of the GFZ for six years and is a Helmholtz International Fellow at the GFZ. The Austrian flood expert says: "Regardless of the necessary efforts of climate change mitigation, we will see the effects of these changes in the next decades. Flood management must adapt to these new realities."

The study in which 35 European research groups were involved evaluated data from 3738 flood monitoring stations throughout Europe. The data cover fifty years between 1960 and 2010: "It has long been suspected that climate change has an impact on the extent of flooding, as a warmer atmosphere can store more water," explains Günter Blöschl. "But that is not the only effect, flood changes are more complicated.

In central and north-western Europe, between Iceland and the Alps, floods are increasing as precipitation increases and soils become more humid. In Southern Europe, on the other hand, flood levels tend to fall - climate change leads to decreasing precipitation and higher temperatures lead to increased evaporation of soil water. In the case of small rivers, however, flooding can increase due to more frequent thunderstorms and changes in land management (e.g. deforestation).

In the more continental climate of Eastern Europe, flooding levels are also decreasing due to less snow in winter. "There are clear flood risk patterns across Europe that match the projected impacts of climate change," says Blöschl. So far, data have not been sufficient to determine whether both the extent and timing of flood events are changing across Europe. Now the authors say: Yes, the effects of climate change are clearly visible here.

The extent of the flood changes is remarkable: they range from a decline in expected flood levels of 23% per decade to an increase of 11% per decade (compared to long-term averages). If these trends continue in the future, significant effects on flood risk are expected in many regions of Europe.
-end-
Original study: G. Blöschl et al.: "Changing climate both increases and decreases European river floods" in Nature, 2019; DOI: 10.1038/s41586-019-1495-6

GFZ GeoForschungsZentrum Potsdam, Helmholtz Centre

Related Climate Change Articles from Brightsurf:

Are climate scientists being too cautious when linking extreme weather to climate change?
Climate science has focused on avoiding false alarms when linking extreme events to climate change.

Mysterious climate change
New research findings underline the crucial role that sea ice throughout the Southern Ocean played for atmospheric CO2 in times of rapid climate change in the past.

Mapping the path of climate change
Predicting a major transition, such as climate change, is extremely difficult, but the probabilistic framework developed by the authors is the first step in identifying the path between a shift in two environmental states.

Small change for climate change: Time to increase research funding to save the world
A new study shows that there is a huge disproportion in the level of funding for social science research into the greatest challenge in combating global warming -- how to get individuals and societies to overcome ingrained human habits to make the changes necessary to mitigate climate change.

Sub-national 'climate clubs' could offer key to combating climate change
'Climate clubs' offering membership for sub-national states, in addition to just countries, could speed up progress towards a globally harmonized climate change policy, which in turn offers a way to achieve stronger climate policies in all countries.

Review of Chinese atmospheric science research over the past 70 years: Climate and climate change
Over the past 70 years since the foundation of the People's Republic of China, Chinese scientists have made great contributions to various fields in the research of atmospheric sciences, which attracted worldwide attention.

A CERN for climate change
In a Perspective article appearing in this week's Proceedings of the National Academy of Sciences, Tim Palmer (Oxford University), and Bjorn Stevens (Max Planck Society), critically reflect on the present state of Earth system modelling.

Fairy-wrens change breeding habits to cope with climate change
Warmer temperatures linked to climate change are having a big impact on the breeding habits of one of Australia's most recognisable bird species, according to researchers at The Australian National University (ANU).

Believing in climate change doesn't mean you are preparing for climate change, study finds
Notre Dame researchers found that although coastal homeowners may perceive a worsening of climate change-related hazards, these attitudes are largely unrelated to a homeowner's expectations of actual home damage.

Older forests resist change -- climate change, that is
Older forests in eastern North America are less vulnerable to climate change than younger forests, particularly for carbon storage, timber production, and biodiversity, new research finds.

Read More: Climate Change News and Climate Change Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.