The increase in eutrophication is the result of human activities. Major sources of nutrients to freshwater and coastal ecosystems include wastewater, agriculture, and atmospheric deposition of nitrogen from burning fossil fuels. The drivers of eutrophication are expected to increase for the foreseeable future. Specifically:
- World population will continue to grow, reaching an estimated 9.2 billion by 2050, which will increase pressures on the productive capacity of agriculture and industry.
- Intensive agriculture and land use conversion—for crops, livestock, and aquaculture—will increase, especially in the developing world. In addition to population growth, intensifi cation is driven by changing dietary patterns. For example, over the period from 2002 to 2030, global meat consumption is expected to increase by 54 percent.
- Energy consumption is expected to grow 50 percent from 2005 to 2030. Fossil fuels, which release nitrogen oxides (NOx) into the environment when burned, will continue to be the dominant fuel source in this century.
As a result of these increasing global trends in population growth, energy use, and agricultural production, we expect that coastal and freshwater systems impacted by eutrophication and hypoxia will continue to increase, especially in the developing world.