Nitrogen and phosphorous are two key nutrients that are natural parts of aquatic ecosystems. Nitrogen is also the most abundant element in the air we breathe. Together they play an important role in the global and local sustainable development agendas.
The use of these nutrients is key to growing crops and thus to the world’s food security. However, in some parts of the world farmers do not have access to enough nutrients to grow crops and feed growing populations. But in many other parts of the world there is an ‘excess’ of nutrients in the environment as a result of industrial and agricultural activity and has profound impacts, from pollution of water supplies to the undermining of important ecosystems and the services and livelihoods they support.
The result is a seeming divide between societal needs for food and energy and a complex web of adverse environmental impacts which undermine the natural resource base and the services and livelihoods it provides. This divide – ‘the nutrient challenge’- is set to intensify, to the cost of countries, as population, food and energy demands increase.
Against this backdrop, the key question that needs to be answered is ‘How to promote effective nutrient management, minimising negative impacts on the environment and human health, while maximising their contribution to global sustainable development and poverty reduction?’ The Global Partnership on Nutrient Management (GPNM) has been launched to address this challenge.
Some Facts and Figures:
- Human activities produce around 120 m tonnes of reactive nitrogen each year, much of which (nearly two thirds) ends up polluting air, water, soil marine and coastal areas, and adding harmful gases to the atmosphere;
- Some 20 m tonnes of phosphorous are mined every year and nearly half enters the world’s oceans - 8 times the natural rate of input;
- Between 1960 and 1990 global use of synthetic nitrogen fertilizer increased more than sevenfold, while phosphorus use more than tripled;
- One half of the world’s population is now thought to depend on nitrogen and phosphorous fertilizers for the production of their food – much of the fertilizers is not used by the crops;
- Worldwide, the number of coastal areas impacted by eutrophication caused by excess nutrients stands at over 500;
- Dead zones in the world’s oceans have increased from 10 cases in 1960 to 405 documented cases in 2008 (169 identified hypoxic areas, 233 areas of concern and 13 systems in recovery);
- Many of the world’s freshwater lakes, streams, and reservoirs suffer from eutrophication – millions of people depend on wells for their water where nitrate levels are well above recommended levels;
- More than 90% of the world's fisheries depend in one way or another on estuarine and near-shore habitats;
- Nitrous oxide is a powerful greenhouse gas – estimated to be responsible on current levels for about 11% of the net anthropogenic global warming potential from such gases.
