CP CHC PictureThe global hydrological cycle includes many different components reacting in complex, dynamic and often non-linear ways to external forcings such as, but not limited to, climate change. While hydrological impacts of climate change – e.g. spatial and temporal alterations in water balance, streamflow and extreme events (floods, droughts) - typically occur at regional or local scales, they can trigger modifications that lead to larger-scale or even global changes in the water cycle.

This Collaborative Programme aims at improving the scientific understanding of hydrological processes under modified climatic boundary conditions and at studying possible impacts of changing hydrological cycle components (precipitation, runoff, snow, etc) on the environment and the society. Meeting emerging societal challenges, in fact, is another aspect this CP intends to address.

Current key topics of the CHC—CP include:

  • Global precipitation changes and runoff. Precipitation changes at the global level display a complex pattern, without a clear-cut average trend in the last century but with an apparent tendency to the intensification of the hydrological cycle in many areas of the world. Using observations and (global to hydrological) model simulations, this research task studies current and expected changes of precipitation at the global and European scale, with a specific focus on extreme episodes and their effects on mean runoff and intense flooding and drought events.
  • Interaction between climate and hydrological/land surface processes. Modifications of the water cycle significantly affect land surface properties and ecosystem functioning and are at the same time driven by changes in vegetation and land surface changes. In order to better understand these complex interactions, this CP uses a hierarchy of models working at different spatial and temporal resolutions, compared to/validated against in-situ and EO data.
  • Climate hot spot regions: Mediterranean region and Global Mountains. The Mediterranean basin and mountains areas are among the regions which are referred to as “climate change hot-spots”. In these regions climate change signals are amplified, as are their possible effects. Studying these areas would allow to develop appropriate adaptation and mitigation measures in the coming decades.
  • Societal challenges related to impact of changes in the hydrological cycle. Among the expected impacts of observed and projected changes in the hydrological cycle are the lack of water for drinking, agriculture, industry and energy production, which imposes risks for civil security. Impact-oriented research aims at effectively responding to crucial societal challenges resulting from changes in different components the hydrological cycle and to support adaptation and risk mitigation strategies. 

See below for more information on the CP structure and tasks, and a factsheet summarizing the CP. A White paper delineating activities and presenting the grand challenges is in preparation and will be published in early 2019.

research topics

CP CHC Picture1

Global precipitation changes and runoff



CP CHC Picture2

Interaction between climate and hydrological/land surface processes



CP CHC Picture3Climate hot spot regions: Mediterranean region and Global Mountains



CP CHC Picture4Societal challenges related to impact of changes in the hydrological cycle



Collaboration (Projects/Initiatives)

For this, the research groups and institutions involved in ECRA collaborate with other European and international scientific initiatives, such as the Belmont Forum with its Collaborative Research Actions (CRAs), the Mountain Research Initiative (MRI) and collaborations with existing national and international projects, e.g. the EU H2020 projects ECOPOTENTIAL, CRESCENDO and PRIMAVERA. New proposals and joint actions will be developed during the research activities.


The CP Changes in the Hydrological Cycle has organised three Workshops, two joint Workshops together with the CP High Impact Events as well as one Policy Briefing at the European Parliament so far. For further information on the Workshops, please follow this link.


The Hydrological Cycle Briefing Document (March 2015) includes a Special Focus on “The changing mountains of Europe – Water resources and ecosystems at risk”. It will be made available for download here soon.

A Factsheet presenting key issues as well as recommendations for research priorities in H2020 and beyond was prepared for ECRA’s General Assembly 2017. It is available for download here.


Coordinated by:

Ralf Ludwig, Ludwig-Maximilians-University Munich, DE, This email address is being protected from spambots. You need JavaScript enabled to view it.

Lisa Palazzi, National Research Council of Italy (CNR), IT, This email address is being protected from spambots. You need JavaScript enabled to view it.

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