Global Stream Flow Study: Water Levels Dropping in Major Rivers
by Derek Markham in Availability, Climate Change, Freshwater Ecosystems
An analysis of the stream flow data for 925 of the world’s largest rivers over the last 56 years has found that rivers in some of the most populated regions are losing water. The authors of the study suggest that the reduced flow is linked to climate change, and say that it could put water and food supplies in jeopardy in the future.
The scientists, from the National Center for Atmospheric Research, examined stream flow from 1948 to 2004 and found significant changes in about a third of Earth’s largest rivers. Some of the rivers actually increased flow, but the losers outnumbered the gainers by a 2.5 to 1 margin. The Colorado, Niger, Yellow, and the Ganges rivers, all serving large populations, were among those found to be channeling less water.
“Reduced runoff is increasing the pressure on freshwater resources in much of the world, especially with more demand for water as population increases. Freshwater being a vital resource, the downward trends are a great concern.” – NCAR scientist Aiguo Dai, lead author
Among the factors affecting river discharge are dams and agricultural and industrial diversion of water, but the researchers found that in many cases, the reduced flows appear to be related to climate change. The altered precipitation patterns and increased evaporation rate from an increase in average temperatures contribute to increased drought conditions. The impact on future water and food supplies may be severe in the affected areas.
“As climate change inevitably continues in coming decades, we are likely to see greater impacts on many rivers and water resources that society has come to rely on.” – NCAR scientist Kevin Trenberth, co-author
The study found that from the years 1948 to 2004, the annual freshwater discharge into the Pacific dropped by around 6%, and the annual flow into the Indian Ocean fell by 3%, but the annual river discharge into the Arctic Ocean rose by about 10%. In the U.S., the flow of the Columbia River dropped by about 14% due to reduced precipitation and high water usage, while the Mississippi River’s flow has increased by 22% over the same period.
Other concerns were raised by the study, such as the effect that reduced freshwater flow can have on the ocean’s circulation patterns, which also affects climate regulation. The lead author says that although the changes in stream flow appear relatively small and may only impact the areas around the mouth of the rivers right now, monitoring of these freshwater flows is necessary to measure long term changes.
The rivers analyzed in the study account for 73% of the world’s total stream flow, and drain water from every major landmass except Antarctica and Greenland. The results will be published on May 15 in the American Meteorological Society’s Journal of Climate.
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Posted on May 04, 2009
Arctic Ocean, Climate Change, Colorado River, Columbia River, Ganges rivers, Indian Ocean, Mississippi River, Niger, rising sea level
About the Author
Derek Markham
Derek Markham is husband, father, and writer based in Colorado, with a passion for all things sustainable. For the last ten years, he's worked in the natural foods industry, most recently running a small co-operative grocery store. Derek enjoys sharing tips, lessons learned, and resources for going green, simple living, and natural parenting. In his personal time, he loves to ride his bike (an 80s Trek singlespeed), go bouldering and slacklining, and he can usually be found in the middle of about ten different books. You can also find him on other sites including Twitter, Twilight Earth, Natural Papa, and Green Options.10 Responses to “Global Stream Flow Study: Water Levels Dropping in Major Rivers”
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[...] Not Ranked : 0 water dropping all over the globe The study seems a bit dubious for some reason, but apparently rivers are running low almost everywhere. I am not sure how we could lose water with the law of the conservation of matter in effect but I am no hydrologist. The water wars will make the oil wars look like fun. Tom Global Stream Flow Study: Water Levels Dropping in Major Rivers | Blue Living Ideas [...]
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[...] According to the following article, scientists have analyzed the flow of rivers around the world and discovered that most are losing water. Â This is particularly troublesome becasue many of the shrinking rivers service densely populated areas. Global Stream Flow Study: Water Levels Dropping in Major Rivers [...]
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[...] Global Stream Flow Study: Water Levels Dropping in Major Rivers … [...]
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May 04, 2009
It’s linked to overpopulation, not global warming. Geeze, is it that hard to figure out that adding billions of people every decade results in more water use, drawn from where? Rivers, Lakes, and Underground Aquifiers (and they’re all interconnected), wow, how did I know that?
Stop with the global warming panic crap. Start talking about being responsible and having fewer than 3 kids.
Stop having more than two children in each family and that would be a good start. It’s called zero growth. And, I’m sorry, if a country can’t feed it’s people, and those people continue to have more and more kids, then stop trying to save them by sending them free food and other assistance. It’s not working.
Allen917
Oct 22, 2009
Don’t worry too much about dropping river levels. Remember we live in a closed system and all that water is still here. We may need to work on the solar powered extraction of fresh water from the oceans, but that is a doable project. Also don’t worry about global climate change, cause Mother Gaia knows what she is doing. Think of climate change as a farmer thinks of crop rotation to preserve and improve the land. As animals and plants will move about to fresh areas to prosper and grow those that can’t adapt are eliminated allowing room for a new a better crop to arise. I find it somewhat arrogant for man to think that all things must remain static. Mother Gaia has been doing this much longer than we have, and with great success I might add.