Credit: Cédric Dhaenens/Unsplash

The planet is losing free-flowing rivers. This is a problem.

Study finds a little more than one-third of the longest rivers on the planet remain unobstructed by human-made changes

Only 37 percent of the world's longest rivers remain unimpeded and free-flowing from their source to where they empty, according to a study published today in Nature.


Free-flowing rivers are ecologically crucial — replenishing groundwater, bolstering biodiversity, and reducing the impacts of droughts and floods.

The study is the first to pinpoint the remaining free-flowing rivers on the planet and suggests economic development via dams, reservoirs, roads and hydropower is leading to decreased connectivity via rivers, which can harm freshwater species and reduce rivers' ability to mitigate floods and drought impacts.

"Rivers are the lifeblood of our planet," said Michele Thieme, lead freshwater scientist at World Wildlife Fund and coauthor of the study, in a statement. "They provide diverse benefits that are often overlooked and undervalued."

Thieme and colleagues looked at the 242 longest rivers across the globe (all longer than about 620 miles). They found 37 percent of the rivers remain free-flowing for their entire length, and only 21 of the world's 91 rivers longer than 620 miles that originally emptied into oceans remain free-flowing.

The authors write than free-flowing rivers remain "prevalent only in remote areas of the world that are difficult to exploit economically (for example, the Arctic), in rivers too large to be developed by current technology, or in less developed regions (for example, the Congo region)."

"Both very long and long free-flowing rivers are largely absent from the mainland United States, Mexico, Europe and the Middle East, as well as parts of India, southern Africa, southern South America, China and much of Southeast Asia and southern Australia," the authors wrote.

Dams and reservoirs are the leading cause for connectivity loss, the authors write, estimating there are approximately 60,000 large dams worldwide, and more than 3,700 hydropower dams are planned or being built. "While hydropower inevitably has a role to play in the renewable energy landscape, well-planned wind and solar energy can be more viable options for rivers and the communities, cities, and biodiversity that rely on them," Thieme said.

Free-flowing rivers are important: they recharge groundwater, remain vital for the survival and health of fish populations, bolster biodiversity by destroying or changing habitats and preventing migration, and transfer sediment to deltas or flood plains, which helps reduce flood and drought risks.

"The world's rivers form an intricate network with vital links to land, groundwater, and the atmosphere,'' said lead author Günther Grill of McGill's Department of Geography, in a statement.

''Free-flowing rivers are important for humans and the environment alike, yet economic development around the world is making them increasingly rare."

See the full study at Nature.

insideclimatenews.org

Coal phase-down has lowered, not eliminated health risks from building energy, study says

Thanks to the phase-down of coal, the risk of premature death in the United States due to the burning of fuels for electricity, homes and businesses fell 54 to 60 percent from 2008 to 2017, Harvard researchers found in a new study.

Get our Good News newsletter

Get the best positive, solutions-oriented stories we've seen on the intersection of our health and environment, FREE every Tuesday in your inbox. Subscribe here today. Keep the change tomorrow.

To reduce carbon footprint, these artists greened up their practice

Passionate about the natural world, some artists are examining how their materials and creative process impact the environment.
yaleclimateconnections.org

New tool called 'Vulcan' could help cities better estimate their carbon dioxide emissions

lot of cities have ambitious goals to reduce greenhouse gas emissions. But to achieve those goals, they first need to know exactly how much carbon pollution they produce now and where it comes from.

www.washingtonpost.com

Biden’s new 30x30 plan offers a broad vision but few details

Months after President Biden set a goal of conserving 30 percent of the nation's land and waters by 2030, the administration Thursday laid out broad principles - but few details - for achieving that vision.

stateimpact.npr.org

To cut methane leaks — and maybe work on their image — 2 Pa. gas drillers eye ‘responsibly sourced’ label

The companies are launching pilot programs to produce gas without harmful methane leaks. There are business reasons to do that, experts say.
www.post-gazette.com

Energy secretary lays out need for funding for clean energy, fossil fuel research near Pittsburgh

Energy Secretary Jennifer Granholm outlined her agency's $46.3 billion budget request before House lawmakers as a necessary investment in clean energy technology, while boosting funding for fossil fuel research at federal laboratories near Pittsburgh.

www.post-gazette.com

EQT ventures into northeastern Marcellus with $2.9 billion deal for Alta Resources

Downtown-based natural gas driller EQT Corp. announced a $2.9 billion acquisition Thursday, expanding its reach into the northeastern part of Pennsylvania. Already...