Earth is covered under 300,000 square miles of rivers and streams, satellite data reveals
New Delhi : In a new discovery, the satellite data reveals unexplored rivers and streams which geologists never estimated before. The new estimate shows that, excluding land with glaciers, Earth is covered by just under 300,000 square miles of rivers and streams. That is more square footage than the state of Texas, and it’s as much as 44 percent higher than previous counts.
The finding has suggestion for the study of climate change, because rivers exchange greenhouse gasses with the atmosphere, especially when humans pollute their waters.
“It was assumed until about 2006 that rivers and lakes were just a pipe transporting carbon to the ocean,” John Downing, a limnologist and biogeochemist at the University of Minnesota Duluth, told Gizmodo. “But the rivers are leaking gasses into the atmosphere.”
As pollutants like fertilizers and sewage seep into water supplies, gasses including methane, carbon dioxide, and nitrous oxide bubble out and drift up into the atmosphere. More river exposure could mean we are sending even more of those greenhouse gasses into the air than current calculations stands for.
“Here’s another reason not to spoil water,” said Downing, who was not involved in the new study. “If you pollute it, you spoil fishing and swimming, but you also spoil the atmosphere.”
To calculate the rivers and streams in our planet, University of North Carolina hydrologists George Allen and Tamlin Pavelsky analyzed thousands of images from a NASA Landsat satellite. Using software developed by Pavelsky, the duo ended up with 58 million river measurements they then used to calculate the total coverage of rivers and streams on Earth.
To make sure the program was reliable, the researchers employed what Allen called “a small army of undergraduates” to carefully monitor whether the program was measuring rivers, not roads, and if it was avoiding other mistakes along the way. “They were so enthusiastic,” Pavelsky said. “They did such a great job.”
The researchers also found that rivers were both narrower and sparser in human-developed areas, which amazed them. This could be because people are draining off water for agriculture, draining swamps and rivers.