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The world's largest rivers flow decreases due to global climate change
That is the conclusion reached by a study from the American Meteorological Society's Journal of Climate. Many people depend on water from these rivers for everything, from agriculture to drinking water. Among them are the Yellow River, the Ganges, the Niger and Colorado, all with a significant decrease in flow.
Scientists at the National Center for Atmospheric Research in Boulder, Colorado, investigated the flow rate of 925 rivers around the world over 56 years, from 1948 to 2004. Using computer models, scientists found that one third of the rivers showed changes in their flow rates, either increases or losses, but mainly, the latter. In most cases, the rivers that experienced increases in their flow, were located in areas of low population density, especially in the Arctic, due to the ice melting.
Research has shown that freshwater reaching the Pacific has fallen by 6%, which equals the volume unloaded by the Mississippi every year.
"Reduced runoff is increasing the pressure on freshwater resources20in much of the world, especially with more demand for water, as population increases," says NCAR scientist Aiguo Dai.
Researchers have linked these changes to climate change, although there may be other factors, such as dams or irrigation.
This decrease in freshwater levels will have a direct influence on food in many places, but scientists are also worried about the effect this may have on the oceans, because rivers discharge nutrients and minerals to them, which are very important for many marine species. The river´s freshwater impacts the ocean currents that could be also affected.
