Climate Change Could Cause 75% of U.S. Rivers to Lose Their Biodiversity, Scientists Warn

As global warming accelerates across the planet, a new study of river systems across the contiguous United States reveals that only 26% of these ecosystems—vital for people and nature alike—are likely to withstand the compounding climate change pressures underway and expected in the future.

Led by researchers from The Nature Conservancy’s Center for Resilient Conservation Science (CRCS), the study—published today in the journal PLOS One—finds that despite 75% of these river systems being at risk of biodiversity loss overall, only 19% of the most biodiverse rivers are currently resilient to climate change.

Working with experts across 44 states, the paper’s authors used mainly publicly available data to map those river systems and watersheds most capable of adapting to rising temperatures, as well as shifting rainfall and snowmelt. The result is a proposed national network of rivers and streams designed to allow nature to move and adapt as the climate changes, safeguarding increasingly vulnerable ecosystems.

Commenting on the paper’s findings, lead author Mark Anderson — a former director of conservation science at TNC who retired from his role leading CRCS following the conclusion of this research — said: “Right across the contiguous U.S., freshwater ecosystems are as indispensable for human lives and livelihoods as they are for nature — and yet thousands have become fragmented by dams that hinder species movement and adaptation, alongside other man-made interventions like water diversions, groundwater extraction and habitat degradation."

"At a time of compounding climate pressures, our study simultaneously highlights the scale of the problem and offers one of the clearest roadmaps to date on where protection and restoration efforts should be targeted in order to sustain America’s aquatic biodiversity in a fast-changing world,” Anderson adds. 

Crucially, the research also highlights the large gap in protection of the most resilient and biodiverse rivers in the Lower 48, finding that the majority are not sufficiently protected against future degradation at present. In doing so, it also reveals the many opportunities available to benefit both nature and people over the coming decades if smart freshwater protection decisions are made today.

Explore study data and maps in more depth via TNC’s Resilient River Explorer and learn more about TNC’s global efforts to conserve freshwater ecosystems for people and nature here.

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Anderson M.G., Olivero A., Barnett A., Khoury M., Martin E. A freshwater resilient and connected network to sustain biodiversity under a changing climate. PLOS One.