Rivers and Streams Cover Much More of the Earth Than We Thought, Which is Bad News

We are very much familiar with the fact that almost 71 percent of the earth’s surface is covered by water. But this water doesn’t just exist in the mighty oceans, it also runs between land surfaces in the form of rivers and streams. These rivers and streams cover a significant amount of area which was thought be to a lot lesser than it actually is according to the latest studies.

Long rivers, like the Amazon in South America, and their tributaries take up a lot more room than we were expecting.

According to the latest research which was published in the journal Science, the rivers and streams on Earth covers at least 44 percent more area than previously estimated. This is big news as these water sources have serious implications on climate change.

To measure the accurate surface area of all the rivers and streams, researchers used satellite data and combined it with on-the-ground measurements. They collected accurate measurements of over 60 millions rivers around the world and created the most detailed database ever compiled. This vast measurement project was named Global River Widths from Landsat (GRWL). The main reason behind this measurement project was to understand the extent to which rivers and streams affect climate change.

Scientists want to use accurate measurements of rivers and streams to study climate change.

There are many man-made processes that release large amounts of carbon dioxide which subsequently contribute adversely towards climate change. These processes include cement factories, chemical factories and fossil fuel-powered vehicles. When compared to all these processes, water only emits about one-fifth of total carbon dioxide. But water in the rivers and streams also releases a significant amount of greenhouse gases, which compelled the researchers to get accurate measurements in order to understand their effect.

The water that flows in the rivers and streams is fresh water, which is different from the saltwater in the oceans. This water flows through different types of soils which, after decomposition, release carbon dioxide and greenhouse gases.

The water in the rivers and streams keeps on flowing with these trapped gases which are eventually released in a process called ‘gas evasion’. Gas evasion is a simple phenomenon of gases separating from water. Scientists are well familiar with this phenomenon so all they needed was accurate measurements of rivers and streams to estimate the effect. Thanks to George Allen (doctoral candidate at University of North Carolina) and Dr. Tamlin Pavelsky (Associate professor at UNC), we now have a database of accurate measurements.

Gases trapped in moving water get released through a process called gas evasion.

The GRWL database is freely available for general public to read and examine. This database revealed that the total surface area covered by rivers and streams is around 773,000 square kilometers. This area is tens of thousands of square kilometers more than the estimated measurements of before.

The findings of the GRWL are clear indication that rivers and streams play a much larger role in climate change than what was previously believed. Now that the scientists have accurate measurements, they can use them to study other effects of rivers and streams, such as flooding and the creation of new landforms.