Only 2.5% of all water on Earth is fresh water, of which less than 1% is accessible – yet this resource is essential for human life. Fresh water is essential for drinking water, agriculture, irrigation, industry and power generation. In addition, 10% of the world’s animal species live exclusively in freshwater habitats, many of which are threatened with extinction.
It has never been so important to protect our freshwater environments. This is acknowledged by the United Nations Sustainable Development Goals, in particular in goal 6: ‘Ensure availability and sustainable management of water and sanitation for all’.
The two important issues with fresh water are its quantity (or scarcity) and quality.
By 2050, nearly half of the world’s population will be living in areas where water is scarce, and over a quarter of cities globally are already facing water stresses. While water scarcity risks are highest in and around the Middle East, this truly is a global problem, with cities such as London, Tokyo, Miami, Bangalore, Moscow and Cape Town at risk. This makes it even more important that we protect the quality of the resource we do have.
The quality of fresh water is just as important as the quantity. Poor water quality is the cause of more deaths each year than from all forms of violence, including wars. Poor water quality is also putting over 50% of freshwater fish species and 30% of amphibians at risk of extinction.
Water quality refers to a range of measures including temperature, pH, nutrient and chemical levels. These levels naturally vary between different freshwater environments, but human activity can cause extreme changes in water quality, from which natural environments cannot always recover.
You will have heard about the devastating impact of oil spills in marine environments, but did you know that our freshwater environments are also under threat, from the chemicals we use across all of our everyday life? This pollution comes from our farms, our homes, our roads, our sewage treatment works and more.
One of the biggest threats to freshwater comes from an excessive inflow of nutrients, in particular nitrates and phosphates. Nitrates and phosphates occur naturally in the environment and are essential for plant growth. Healthy freshwater ecosystems usually have very small amounts of nutrients – just enough to sustain the plants that live there. However, human activity on land can cause extra nutrients to get into the water. Nutrients are commonly present in domestic and industrial waste and sewage, as well as in the fertilisers that wash off of farmland and into rivers, lakes and streams.
When too many nutrients are present in fresh water, an effect called ‘eutrophication’ occurs. The extra nutrients feed the rapid growth of algae, leading to dangerous algal blooms which can suffocate other life. The decline in quality of the environment means that our water needs heavier treatment before it is safe to drink and to use. Our food can become contaminated and other services that natural ecosystems provide, like regulating the climate and storing carbon, are being hampered. This can have a widespread impact on our lives.
Nearly all freshwater environments are impacted by man-made pollutants. This is why we created FreshWater Watch, to monitor the lakes, rivers, streams, wetlands and reservoirs on which we all depend. Through understanding the areas and causes of pollution, we can direct targeted mitigation to improve water quality and protect freshwater environments.