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Understanding the Link Between Groundwater, Human Activities and Climate Change: The Case of Europe


Lorenzo Copia, Isotope Analyst, demonstrates how some naturally occurring radioactive isotopes present in water—such as tritium, carbon-14 and noble gas radioisotopes—are used to estimate groundwater age. (Photo: O. Yusuf/IAEA)

Despite the global attention to climate change, the direct and indirect effects of climate change on groundwater resources remain underexplored. In the coming decades, a constellation of factors—from agricultural and industrial activities to the growing variability of weather patterns—may have severe consequences for the availability of groundwater. In February, 22 counterparts from across Europe and Central Asia, supported by IAEA experts, gathered at the Agency’s Vienna headquarters to explore the current status of isotope hydrology in the region and future ambitions for its use, and to develop plans on how to work together to assess groundwater resources using nuclear and isotopic techniques.

Groundwater is the planet’s largest distributed store of freshwater. The strategic importance of groundwater, for both global water and food security, is expected to grow as climatic variability increases. “In order to develop adequate mitigation and adaptation strategies, national authorities and decision makers need to understand how climate change can affect water resources and water related infrastructures,” said Oliver Kracht, IAEA isotope hydrologist.

The direct impacts of climate change on groundwater systems are mainly linked to observed and projected increases in temperature and average global sea levels, as well as to growing variability in precipitation. But climate change affects us indirectly, as well, through changing land-use patterns and through the intensified use of groundwater for human activities, which increases demand for this resource.

Takuya Matsumoto, an Isotope Analyst working in the IAEA’s Isotope Hydrology Laboratory, explains how an assessment of noble gases in sampled groundwater can help experts to deduce its age. (Photo: O. Yusuf/IAEA)

At the February meeting, counterparts and experts discussed the extent to which isotopic techniques are included in their respective national hydrological assessments strategies, to identify incomplete or deficient isotopic information and, to agree upon approaches for regional knowledge- and information-sharing aimed at filing these gaps.

“The nuclear techniques have already proven to be very useful in giving answers to hydrology problems,” said Paula Carreira, a researcher in Portugal’s Superior Technical Institute. “For example, the use of carbon-14 in dating groundwater systems was applied in Portugal to identify potential water resources that are well protected from human actions. At the same time, chemical and isotopic parameters can help us to identify pollution sources and to delimit groundwater recharge protection zones.”

The IAEA has been a key point of reference for the development and dissemination of isotope data in hydrology since the 1960s, thanks to its  Global Network of Isotopes in Precipitation, established jointly with the World Meteorological Organization. At the same time, the Agency’s technical cooperation (TC) programme has helped countries to acquire critical equipment, as well as delivering training in the application of isotope hydrology and building national capacity. This IAEA support has provided countries with the capacity to collect and analyse data on the origin, size and age of groundwater resources—data  that are essential for policy-makers to make informed resource management decisions.

A new regional technical cooperation project[1] launched in January 2020 aims to support national efforts to integrate isotopic techniques into national hydrological assessments, so that the countries can subsequently develop sustainable water-use policies.

Held from 3 to 7 February, the coordination meeting benefitted from the close participation of experts and counterparts from across the Europe region. (Photo: O. Yusuf/IAEA)

“The cornerstone of the project is cooperation between several isotope hydrology laboratories in the Europe and Central Asia. We plan that these cooperating groups will team up with institutions in the region that are more advanced in isotope hydrology,” said Christoph Henrich, IAEA Programme Management Officer. “Our goal is that these teams will answer common and transboundary water resources management-related research questions that can be examined using  isotope hydrology.”

During the meeting, the participants agreed to develop eight, separate isotope hydrology case studies on the effects of external factors on  the quality and quantity of groundwater.

One case study will use isotope techniques to investigate a transboundary aquifer lying between Montenegro and Bosnia and Herzegovina, with the aim of better delineating the catchment area of the aquifer, as well as identifying the vulnerability of karstic springs to climate change.

Another study will focus on the influence of climate change on groundwater resources in the Sava River Basin, which is shared by Slovenia, Croatia, Serbia and Bosnia and Herzegovina. Finally, littoral countries participating in the project will investigate whether evolving human and environmental factors—such as rising sea levels caused by climate change or the extensive pumping of groundwater resources—may lead to salt-water intrusion in coastal aquifers.

These case studies, among others launched through the project, will enhance cooperation in the field of water and isotope hydrology in the region, and at the same time will support the development of new technical capacities and competencies in the participating countries. They are expected to help clarify persisting issues in the region related to the sustainable management of water resources.

[1] RER7013, ‘Evaluating Groundwater Resources and Groundwater-Surface-Water Interactions in the Context of Adapting to Climate Change’

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