The Colorado River (U.S.) is among rivers worldwide that have been affected by a warming Earth.
Click on image for full size
Courtesy of U.S. Geological Survey
As World Warms, Water Levels Dropping in Major Rivers
News story originally written on April 21, 2009
About one out of three of the world’s largest rivers have been changing over the past few decades. Most of those rivers now carry less water.
A team of scientists from the National Center for Atmospheric Research (NCAR) studied 925 of the Earth’s largest rivers. These rivers hold about three-quarters of all the water flowing through rivers worldwide.
They looked at data about how much water was in rivers between 1948 and 2004 and found that rivers are loosing water in some places where there are large human populations. Less water in the rivers may mean that there will be less food and water for people living in those regions.
"Reduced runoff is increasing the pressure on freshwater resources in much of the world, especially with more demand for water as population increases," says scientist Aiguo Dai, who led the study.
The scientists found that less water in these rivers appears to be related to global climate change. Climate change is causing amounts of precipitation to change in different regions of the world. Warmer temperatures are also increasing the amount of evaporation.
The scientists also found that there is now more water flowing in rivers in the Arctic where snow and ice are melting as the planet warms.
"As climate change inevitably continues in coming decades, we are likely to see greater impacts on many rivers and the water resources that society has come to rely on," says scientist Kevin Trenberth.
Last modified September 4, 2009 by Lisa Gardiner.
Shop Windows to the Universe Science Store!
Our online store
includes issues of NESTA's quarterly journal, The Earth Scientist
, full of classroom activities on different topics in Earth and space science, as well as books
on science education!
You might also be interested in:
Rivers are very important to Earth because they are major forces that shape the landscape. Also, they provide transportation and water for drinking, washing and farming. Rivers can flow on land or underground...more
One process which transfers water from the ground back to the atmosphere is evaporation. Evaporation is when water passes from a liquid phase to a gas phase. Rates of evaporation of water depend on things...more
Scientists have learned that Mount Hood, Oregon's tallest mountain, has erupted in the past due to the mixing of two different types of magma. "The data will help give us a better road map to what a future...more
The Earth's mantle is a rocky, solid shell that is between the Earth's crust and the outer core, and makes up about 84 percent of the Earth's volume. The mantle is made up of many distinct portions or...more
Some geologic faults that appear strong and stable, slip and slide like weak faults, causing earthquakes. Scientists have been looking at one of these faults in a new way to figure out why. In theory,...more
The sun goes through cycles that last approximately 11 years. These solar cycle include phases with more magnetic activity, sunspots, and solar flares. They also include phases with less activity. The...more
Studying tree rings doesn't only tell us the age of that tree. Tree rings also show what climate was like for each year of a tree's life, which means they can tell us about climates of the past and about...more