Beavers, those iron-toothed rodents with a talent for hydraulic engineering, can legally return to English river catchments after an absence of 500 years.
Castor fiber has been on the way back for the last two decades thanks to unauthorised reintroductions. But until a few weeks ago, an enclosure was the only home these semi-aquatic mammals could legally find in the UK.
Successive governments have hesitated to issue release licenses for beavers, given their ability to transform the environment in unpredictable ways. When it comes to mitigating and adapting to climate change, however, that’s their biggest asset.
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When the reign of Tyrannosaurus rex abruptly ended 66 million years ago, a “prehistoric beaver” was on the ascendancy according to Stephen Brusatte, a palaeontologist at the University of Edinburgh.
“It wasn’t a good time to be alive,” he says. An asteroid had smashed into Earth with the equivalent fury of several million nuclear bombs. But Kimbetopsalis simmonsae, with its buck-toothed incisors and appetite for leaves and branches, survived.
Within a few hundred thousand years, lush forests had returned. Filling the vacant niches left by vanished dinosaurs were mammals like Kimbetopsalis.
“This burst of evolution led to primates, which eventually led to us,” Brusatte says.
Beaver-like ancestors braved a mass extinction event to help mammals rise from the ashes. What could modern beavers do during another era of planetary crisis?
Read more:
How we found ‘prehistoric beaver’ that helped mammals inherit Earth after dinosaurs were wiped out
Dam the carbon
Legal protections and synthetic materials that reduced demand for warm fur have allowed beavers to regain their former haunts in Europe and North America.
The famously industrious rodents have wasted no time in picking up where they left off: damming streams to create ponds in which they build their dome-like lodges, safe from predators that might prowl the banks opposite.
Ebenart/Shutterstock
This behaviour has a stunning effect on the surrounding environment – perhaps even the climate. That’s because beaver dams trap vast quantities of sediment rich in carbon that might otherwise heat the atmosphere, says Christine E. Hatch, a professor of geosciences at UMass Amherst.
You should take this good news with a pinch of silt, however. CO₂ emissions from human activity were probably well over 40 billion tonnes last year – another annual high. Expecting beavers to offset our emissions is unrealistic, not to mention unreasonable.
Beavers may be skilled at stowing carbon in the wetlands they create, but this advantage is being undone by feedback mechanisms kickstarted by climate change. For example, the warming Arctic is inviting beavers to expand northwards. Here, their antics threaten to speed up the thawing of permafrost that has kept world-warming methane locked up says Helen Wheeler, a lecturer in wildlife ecology at Anglia Ruskin University.
Read more:
Arctic heatwave: what warmer summers mean for the region’s wildlife
Shelter from the storm
Where beavers really shine is in their knack for soothing damaged landscapes.
“Renowned engineers, beavers seem able to dam any stream, building structures with logs and mud that can flood large areas,” Hatch says.
“As climate change causes extreme storms in some areas and intense drought in others, scientists are finding that beavers’ small-scale natural interventions are valuable.”
The changes beavers make can help land hold onto water and release it slowly, which eases flooding and stalls drought. Compare this with human design innovations like tarmac, which radiates heat and allows storm water to slough off in torrents.
While the concrete dams that people construct bar the way for migratory freshwater fish, some of Earth’s most threatened animals, beaver dams present no such obstacle.
“One reason may be that the fish can rest in slow pools and cool pond complexes after navigating the tallest parts of the dams,” Hatch says.
Beaver wetlands do excel in blocking one thing, however: wildfires.
“Recent studies in the western US have found that vegetation in beaver-dammed river corridors is more fire-resistant than in areas without beavers because it is well watered and lush, so it doesn’t burn as easily,” Hatch says.
All of these qualities make beaver wetlands a fantastic refuge for a range of wildlife, particularly as ecosystems nearby are wracked and warped by rising temperatures and extreme weather. Even our towns and cities could be made more liveable with their help, as water evaporating from these ponds cools the air during heatwaves and absorbs flood water during a deluge.
Geographers Joshua Larsen (University of Birmingham), Annegret Larsen (Wageningen University) and Matthew Dennis (University of Manchester) are slightly more cautious.
“Unless the water bodies are very large, or high in number, this [effect] tends to diminish rapidly with distance from the water. This would make it difficult to rely upon beaver ponds for cooling benefits for human settlements,” they say.
Nonetheless, allowing beavers to recover a fraction of their former abundance will make the effects of global heating less severe.
“Beavers are showing that their impacts can offer added levels of ecosystem resilience to a changing climate that we would be wise to embrace,” they add.
The post “Beavers can help us adapt to climate change – here’s how” by Jack Marley, Environment + Energy Editor, UK edition was published on 03/13/2025 by theconversation.com