Earth surface covered by rivers and streams 45 pc higher than thought

How much of the earth is covered by rivers and streams? The surface area of rivers and streams in the world is about 45 per cent higher than estimated earlier, say scientists in a new study.

The study by US researchers made new calculations to find out how much of the earth is covered by rivers and streams.

The researchers, from the University of North Carolina at Chapel Hill and Texas A&M University in the US, used satellite images, on-the-ground measurements and a statistical model in their studies.

Rivers and streams are a major source of greenhouse gas emissions, so higher river and stream surface area calculations has important implications for understanding carbon emissions.

“As we try to mitigate the effects of climate change, it’s really important that we clearly understand where the carbon that we are emitting goes, and that requires us to accurately quantify the global carbon cycle,” said Tamlin Pavelsky, associate professor at UNC-Chapel Hill in a report by PTI.

“Our new calculation helps scientists better assess how much carbon dioxide is moving from rivers and streams into the atmosphere each year,” said Pavelsky.

This research differed from past studies of global river and stream surface areas that were based on theoretical extrapolations of small amounts of actual data.

In this study, published in the journal Science, the research team was able to directly measure both the smallest streams and world’s largest rivers through on-the-ground measurements and satellite images, and then use a statistical model to estimate river and stream coverage across the globe.

As part of the study, the researchers built the Global River Widths from Landsat database, which contains almost 60 million measurements of river width worldwide.

NASA will use data from this research to identify river segments during its NASA Surface Water and Ocean Topography (SWOT) satellite mission, which will launch in 2021. The mission will be NASA’s first satellite mission specifically focused on measuring rivers and lakes.

(With inputs from AP/PTI)