The global freshwater crisis fueled by pollution overuse and climate change

Water quality has been steadily declining, driven by agricultural runoff, urbanisation, industrial pollution, and climate change. One of the most severe consequences of nutrient pollution is eutrophication, where excess nutrients like nitrogen and phosphorus cause algal blooms, reducing oxygen levels in water and damaging aquatic ecosystems. This phenomenon has been increasingly observed in regions such as Asia, South America, and Africa, where agricultural practices contribute heavily to nutrient runoff. The impact is far-reaching—beyond disrupting aquatic life, it threatens human health, particularly in areas dependent on contaminated water for drinking and irrigation.

Pollution of freshwater is not just limited to agricultural runoff. Around 42% of global municipal wastewater sewage is still discharged into the environment untreated, with domestic and industrial wastewater production reaching 359 billion cubic meters annually in 2021—roughly double the flow of the Danube River. This untreated wastewater further degrades water quality, exacerbating risks to ecosystems and public health. In 2022, about 22% of the global population used drinking water sources contaminated with sewage, particularly in densely populated regions of Africa, Asia, and Latin America. The resulting microbial contamination poses the greatest health risk to safe drinking water globally.

Since 1980, global freshwater withdrawals, currently estimated at 4,300 km³ per year, have nearly doubled

Climate change is exacerbating these water quality problems by raising temperatures in freshwater bodies, accelerating chemical reactions, and promoting the growth of harmful algae. Warmer waters not only disrupt aquatic life but also increase the persistence of waterborne pathogens like E. coli, further compromising water safety. Changing precipitation patterns also intensify the problem, with floods introducing large amounts of pollutants into freshwater systems, while droughts concentrate contaminants in shrinking water bodies. These extremes threaten both the availability and safety of water for consumption and agricultural use.

At the same time, water scarcity is becoming an increasingly pressing issue. Since 1980, global freshwater withdrawals, currently estimated at 4,300 km³ per year, have nearly doubled. Agriculture remains the largest consumer, and this growing demand, compounded by population growth and industrialisation, is making freshwater resources more difficult to access. This is particularly critical in areas like Northern Africa and Western Asia, where water stress is severe. In South America, the construction of dams has disrupted water cycles, affecting fisheries and local ecosystems. Rising sea levels, driven by climate change, also threaten freshwater supplies, particularly in coastal regions, by causing saltwater intrusion into aquifers.

Globally, groundwater supplies about 25% of the water used in irrigated agriculture. However, groundwater levels have been declining in more than 30% of the world’s regional aquifers since 2000. While groundwater depletion has slowed in 20% of these aquifers and reversed in 16%, many regions continue to experience water stress. The overuse of groundwater has not only depleted water reserves but also led to land subsidence, further threatening agricultural productivity and water availability.

The potential for water conflict is rising as many of the world's freshwater resources are shared across borders. Transboundary rivers and lakes account for about 60% of the world’s freshwater, and the lack of effective cooperation between countries poses significant risks. Only a small fraction of countries with shared water resources have management frameworks in place, which increases the potential for disputes. In 2023, there were 379 water-related conflicts, highlighting the growing geopolitical risks tied to water security.

Indigenous communities, often living in areas dependent on pristine freshwater ecosystems, are particularly vulnerable. Water disruptions—whether through pollution, overuse, or climate impacts—threaten not only their livelihoods but also their cultural identities, as many Indigenous peoples have deep spiritual and cultural connections to the water sources they rely on.

Freshwater ecosystems are experiencing the highest rates of biodiversity loss, with an estimated 89 species confirmed extinct and 178 more suspected extinct. Around 24% of freshwater species are threatened with extinction, driven by habitat fragmentation, invasive species, overexploitation, pollution, and climate change. Among these ecosystems, wetlands face the greatest threats, vanishing three times faster than forests. The loss of biodiversity in these habitats directly impacts the human populations that depend on them for clean water, food, and livelihoods.

The challenges facing freshwater systems require urgent and coordinated action. Effective water management, pollution control, and strategies to mitigate climate change are crucial to ensuring that water resources are preserved for future generations. The Global Environment Outlook 7 emphasises the importance of integrated water resources management (IWRM), which can help balance competing water demands while safeguarding ecosystems. Increased investment in water infrastructure, especially in vulnerable regions, is also essential for providing equitable access to safe drinking water.

The report also highlights the role of advanced technologies, such as remote sensing and AI-based monitoring, in improving water management and detecting pollution early. However, these tools must be made accessible to all nations, particularly in the Global South, to bridge the technological divide.

As the world faces escalating environmental challenges, it is clear that freshwater systems are vital not only for human survival but also for the health of ecosystems and the stability of the global economy. Protecting water is an urgent necessity that demands immediate attention to secure a sustainable future.