Living within safe and just Earth System Boundaries for blue water

17 November 2023, by MIN-Dekanat

Photo: unsplash/David Becker

In a new paper, Earth Commission experts, including researchers from the Department of Biology at Universität Hamburg, investigate how to ensure the basic water needs of the world’s population can be met in a safe and just manner.

About one third of the global population live in river basins where, in order to stay within safe and just boundaries for water, their basic water needs cannot be met from surface flows alone.

Earth Commission experts build on previous safe and just boundaries research for surface and groundwater, and tackle water scarcity questions by integrating blue water volumes required to provide minimum access to water for basic human needs. Blue water is defined as water sources found in rivers, lakes, groundwater or frozen in glaciers and polar ice caps.

“We have been using our water in ways that negatively affect aquatic ecosystems and other people who rely on renewable freshwater supplies. This also affects the ecosystem services provided by aquatic ecosystems such as reliable clean water supply and fisheries production.” said lead author, Ben Stewart-Koster, Earth Commission expert and Senior Research Fellow, Australian Rivers Institute, Griffith University.

The paper identifies that in some regions, the deficit could be met from a relatively low proportion of available groundwater. However, they also discover that in many drier and more populous regions, 50 percent or more of the average annual groundwater recharge would be required to close the gap.

Groundwater is an important source of water around the world, however, in many regions climatic driven declines in annual groundwater recharge increase the challenge of meeting the needs of people in a sustainable manner. 

In dire need of transformation

The authors conclude that radical transformations are required to meet the basic water needs of all people (just access) while respecting the safe and just Earth System Boundaries for blue water. They outline that changing the way we use water is a critical step to prevent the ongoing loss of freshwater biodiversity and meeting the needs of people within safe and just Earth System Boundaries.

"There is an urgent need for global collaboration to radically transform and recalibrate our water management approach, adopting more efficient practices in food production, reducing urban water consumption, balancing the use of surface and groundwater, and optimizing diverse water sources. Such measures are crucial for preserving biodiversity and maintaining essential ecosystem services like clean water and healthy fisheries that are crucial for our survival", says Dr. Awaz Mohamad, Postdoctoral Researcher at the  Functional Forest Ecology group of the Department of Biology at Universität Hamburg and one of the authors.

„There have been substantial improvements in producing more food with less water and our research has highlighted where demand side transformations such as this are needed to ensure the basic water needs of the world’s population can be met in a safe and just manner”, says Earth Commissioner Prof. Stuart Bunn, Australian Rivers Institute, Griffith University and co-author of the paper.

Text: Earth Commission, red.