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The NASA satellite shows that the Earth has 44 percent more rivers than expected



W With more than 1,300 satellites orbiting the Earth at any one time, you would think we knew all about this planet, what there is to know. But the age of exploration is far from over, researchers point out in a new study Science which was released on Thursday. Just as Hernando de Soto discovered the great Mississippi in 1541, researchers from the University of North Carolina at Chapel Hill and Texas A & M University have mapped a variety of new rivers and streams, showing that we have 44 percent more of them than ever

The NASA-funded researchers led by Tamlin Pavelsky, Ph.D., associate professor of global hydrology at UNC-Chapel Hill, were not fame for the discovery. Rather, they sought to find out how much water is moving on Earth, because rivers and streams add a lot of carbon dioxide to the atmosphere and worsen the effects of climate change. It's important to know where carbon goes, they suggest in the paper, because if we can not track it, we can not quantify how bad our situation really is.

"Our new calculation helps scientists better estimate carbon dioxide moves from rivers and streams into the atmosphere every year," said Pavelsky in a statement released Thursday.

  A snake in the landscape
Rivers, like the Canaima pictured here, can absorb carbon dioxide in the air.

Although much of the focus on climate change on gaseous emissions to the atmosphere by burning fossil fuels, the carbonaceous pollution concentrated in our rivers and streams (such as fertilizer and human and animal) may also release carbon dioxide into the air. This "outgassing" of rivers and streams, the team writes, introduces a volume of carbon dioxide into the atmosphere "about one-fifth of the combined emissions from fossil fuel combustion and cement production."

Since Release of Dissolved Carbon Dioxide In the air of rivers and streams occurs at the water surface, it is important to know how much surface is actually covered by running water. Therefore, the team turned to the images of NASA's Landsat satellite, which they used to create a database called Landsat's Global River Aries (GRWL), which contained over 58 million measurements of rivers over 30 meters wide

  rivers Landsat (GRWL) Database
The line graph (right) shows river coverage as a percentage of land area by latitude, and missions show the density of

By feeding the GRWL data into a statistical model built by Pavelsky, the team calculated the entire surface of the earth covered by streams and rivers. In total, they measured about 773,000 square kilometers (298,457 square miles), about the size of Italy or the Philippines. This is much more agile water – and much more space for carbon dioxide exchange – than we ever thought, which is problematic.


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