When people use freshwater beyond a physically sustainable rate, it causes a cascade of impacts on ecosystems, people and the planet. These impacts include groundwater wells drying up, fish stocks being stranded before they can spawn, and protected wetland ecosystems turning into dry landscapes.
Developments in computer and satellite modeling have fostered a new understanding of how freshwater is being redistributed on the planet and made clear the central role people play in this change. This human impact is so significant that organizations such as the US Geological Survey are redrawing their water cycle diagram to include the impacts of human actions.
Equally important to understanding how people affect freshwater availability is understanding how people and ecosystems will respond to amplified freshwater challenges, such as drought, water stress, and groundwater depletion. Although these challenges affect localized places, their impacts are dispersed throughout the world. To address this global water crisis, urgent global action is needed.
In our recent study, we identified the world’s basins most likely to be affected by two central and interrelated aspects of water scarcity: freshwater stress, which occurs when water consumption exceeds renewable water supply, and loss of freshwater storage, which is the depletion of freshwater in reservoirs or groundwater bodies due to persistent overuse.
Global basins affected by water scarcity
We identified 168 basins worldwide that are most likely to suffer social and ecological impacts due to insufficient freshwater availability. These hotspot basins are found on every continent, a clear indication of the global and pervasive nature of these challenges.
Hotspot basins (in orange and red), which are the basins most likely to suffer severe social and ecological impacts due to limited freshwater availability.
(Xander Huggins)
To identify these hotspot basins, we assessed freshwater stress patterns and freshwater storage trends and compared them to patterns of society’s ability to adapt to environmental hazards and to indicators of ecological sensitivity based on fresh water.
Hotspot basins are the most vulnerable in large part because they are likely to experience social and ecological impacts at the same time. People and societies depend on freshwater ecosystems for drinking water, irrigation water, water filtration, erosion control, as cultural sites and for recreation. This means that the ecological impacts of freshwater stress and storage loss double the social impacts due to the degradation of ecosystem services.
Management of vulnerable basins
Hotspot basins are vulnerable as they are likely to face impacts such as low flow harming aquatic biodiversity, reduced food security as agriculture is heavily dependent on freshwater supplies, wells drying up and a greater potential for social unrest.
A decrease in the supply of fresh water can affect food security, as the agricultural sector is highly dependent on it.
(Shutterstock)
Reducing vulnerability in intertwined social and environmental systems requires better integration of policies and management across sectors. Integrated water resource management considers and balances social, ecological and hydrological sustainability objectives by coordinating management across water, land and other related resources. Its inclusion in the framework of the Sustainable Development Goals of the United Nations highlights its importance.
Our research found that countries such as Afghanistan, Algeria, Argentina, Egypt, India, Iraq, Kazakhstan, Mexico, Somalia, Ukraine, Uzbekistan and Yemen have hotspot basins, but with very low implementation levels of integrated management practices necessary
Prioritize hotspot basins
The location of hotspot basins around the world emphasizes the need for global and urgent action. Prioritizing regions based on their potential to experience social and ecological impacts can improve the effectiveness of global freshwater sustainability initiatives.
Our study calculated how vulnerable all of the world’s watersheds were to the social and ecological impacts of freshwater stress and storage loss. We have identified the most vulnerable watersheds as hotspots for global prioritization. However, although we focus on identified hotspot basins, this does not mean that impacts cannot occur in basins with lower vulnerabilities.
A dry stretch of the Cowichan River on Vancouver Island, BC
THE CANADIAN PRESS/Kevin Rothbauer
For example, only a few Canadian watersheds, all located in the prairies, are identified as having moderate vulnerability in our global study. However, dry streams on Vancouver Island, falling groundwater levels in the Lower Mainland, drought-affected crop yields on the prairies, and the potential for saltwater intrusion along east coast are examples of freshwater security challenges facing Canada.
With the planned massive expansion of irrigated agriculture in Saskatchewan and increasing water scarcity in British Columbia, Canada’s current (and enviable) position of being able to proactively address security challenges of water is decreasing rapidly.
Global action starts locally
Although our study was globally focused, the approach of mapping vulnerability to guide priority setting can be applied to other geographic scales. For example, this analysis could be refined and applied to Canada or to specific provinces or cities using globally unavailable data that may be available for those jurisdictions.
Such insights could help increase the urgency to act on the emerging national water crisis, help modernize the Canada Water Act, or help identify communities that will benefit most from water sustainability plans. water in British Columbia.
Although global studies such as ours are useful in systematically highlighting regions to prioritize, they do not—and should not—provide explicit solutions. Rather, in such complex social and ecological environments, actions to reduce impacts must be tailored to social norms, cultural values, hydrological conditions, and local, place-based knowledge systems.
Our hotspot basins can help guide this local, community-driven action to help conserve the freshwater resources that are most threatened and mitigate the ripple effects of these threats on people and ecosystems.