Data collected with the help of nuclear techniques will play an increasingly important role in mitigating and reducing the impact of climate change on ever scarcer water resources, concluded an event organized by the IAEA and the World Meteorological Organization (WMO) at the 26th United Nations Climate Change Conference (COP26) in Glasgow, the United Kingdom.
The world is facing an escalating freshwater crisis. Climate change has significantly disrupted the water cycle, leading to shifts in precipitation patterns that cause extreme floods and droughts. As a result of rising temperatures, glaciers are melting, ocean and sea levels are rising and water bodies, such as lakes, are evaporating at increasing rates. Experts use isotopic techniques to monitor and study these shifts to better understand how climatic changes impact water availability around the world and to improve existing water management practices to conserve water for generations to come.
"Isotopes are powerful tools applied to assess region-specific climate changes in the past, present and future," said IAEA Director General Rafael Mariano Grossi. "Isotopic techniques are green, affordable and easy to use, and are an ideal method to better understand climate dynamics on a global scale."
When water moves through the different stages of the hydrological cycle, the oxygen and hydrogen isotopes in water molecules get redistributed. Isotopes contain the same number of protons and electrons but can contain varying number of neutrons - this means that their chemical properties are the same but can be distinguished based on molecular weight. The redistribution of isotopes provides water molecules with a unique isotopic composition, which acts as an isotopic fingerprint that informs us on the history of water and the path it followed. This, in turn, provides the scientific fats on which decisions to protect precious water stocks, both above and below the ground, can be based.
"The IAEA-WMO partnership is a testimony that nuclear science and technology support direct climate action," said Elena Manaenkova, WMO's Deputy Secretary General. "Isotope science helps us to understand where water comes from and how we can improve interdisciplinary and international cooperation."
As fresh water around the world is decreasing in quality and quantity, many countries are turning to groundwater as a source of drinking water. In fact, groundwater provides half of all potable water already globally, and climate change is severely affecting the availability of this strategic water resource worldwide.
By studying the age and replenishment rate of groundwater using isotopic fingerprinting, experts can quickly determine how these strategic water supplies can be exhausted and how vulnerable they are to pollution.
The more data we have on water, the better we can understand the shifts in its cycle caused by climate change.
Collecting data from Antarctica to the Arctic
To find data to investigate and optimize the use of groundwater and other water sources, scientists and practitioners turn to the Global Network of Isotopes in Precipitation (GNIP). Maintained by the IAEA and WMO for more than 60 years, GNIP is the world's largest collection of information on water isotopes in the atmosphere.
"The unique added value of GNIP is that it provides information on the hydrogen and oxygen isotopes, which form the water molecule," said Jodie Miller, Head of the IAEA Isotope Hydrology Section. "There are other isotopes in water, but it is by examining the isotopic values of the H2O molecule itself that scientists can determine the water's age, origin and movement."
This data is also extensively used by experts to establish climate models, complex mathematical equations illustrating processes and interactions determining the Earth's climate. Climate models are used to examine climate behaviour and define to which extent observed climate changes are caused by human activities, said Ana Maria Duran Quesada, Associate Professor at the University of Costa Rica.
GNIP houses monthly isotope records at over 1100 sites located in more than 90 countries - from Antarctica to the Arctic and everywhere in between, including remote islands in the middle of oceans and the world's major cities. This data is accessible online to researchers and practitioners. In the last 60 years, GNIP has collected more than 130,000 monthly isotope records in collaboration with many contributors from around the world.
"Water scarcity is a global problem, and it requires international collaboration," said Miller. "The IAEA is inviting countries to be part of GNIP - the more data we have on water, the better we can understand the shifts in its cycle caused by climate change."
Following the signing of an amended agreement at the event, the IAEA and WMO will work on establishing databases and networks to include additional hydrological components, such as rivers and lakes. This will further improve our understanding of the impact of climate change on water availability and will give us the tools to mitigate global water scarcity caused by rising temperatures.
"Through this renewed IAEA-WMO agreement we aspire to link a broader science community to work with us to create and analyse relevant water data. This is about helping everyone to better understand how we can provide resilient water solutions to mitigate the effects of climate change and to help reducing greenhouse gas emissions," said Johannes Cullmann, Director of Water and Cryosphere at the WMO.
The work of GNIP is key to the science-based protection of water resources, said Paul Monks, Chief Science Advisor at the United Kingdom Energy Department.
"GNIP is a unique monitoring and data collection system allowing genuine insights into one of the most dynamic and essential parts of the hydrological cycle," he said. "[…] We do face a climate challenge but without these high-quality data sets we will not be able to deliver those insights or the underpinning of those changes that we are seeing and the recovery we hope to see in the coming years."
