Beavers Could Be a Small Climate-Change Weapon

Scientists are exploring whether beavers could play an unexpected role in addressing climate change. A new international study focusing on a Swiss stream where beavers have been active since 2010 suggests their impact may be significant.

Researchers discovered that wetlands shaped by beaver dams can store carbon at rates far higher than similar areas without beavers. According to the study, these wetlands captured between 108 and 146 tons of carbon each year. That amount of stored carbon is roughly comparable to the emissions produced by burning 832 to 1,129 barrels of oil.

The animals influence the landscape in several ways that help trap carbon. By slowing the flow of water, catching sediment, and expanding wetland areas, beavers change how carbon dioxide moves through the environment. Joshua Larsen, the study’s lead author, explained that these changes fundamentally alter the movement and storage of CO2 in the surrounding ecosystem. The findings were published in the journal Communications Earth & Environment.

Researchers also found that sediments within beaver-created wetlands contained as much as 14 times more inorganic carbon than nearby forest soils. A large portion of the long-term carbon storage comes from dead wood that washes in from surrounding forests, which accounts for nearly half of the carbon held in these areas over time.

One important aspect of the discovery is how long the carbon can remain stored. According to the researchers, the carbon captured in these beaver-shaped wetlands can stay locked away for decades. As long as the dams remain intact, the wetlands function as stable, long-term carbon sinks.

The study also estimated the broader impact beavers could have. If beavers were able to return to all suitable floodplain areas across Switzerland, their wetlands might offset between 1.2% and 1.8% of the country’s annual carbon emissions. Researchers noted that this environmental benefit would come naturally, without requiring direct human management or additional costs.

The European beaver was nearly wiped out during the 1800s due to heavy hunting but has been gradually reintroduced in parts of Europe in recent decades. Early on, some people viewed the returning animals as a potential invasive problem. However, scientists say the European beaver typically feeds on grasses and shrubs close to riverbanks and generally builds smaller dams along secondary and tertiary streams.

Researchers involved in the study say the situation differs from areas where non-native beavers have been introduced. In parts of Patagonia, for example, American beavers have caused large areas of tree loss because they are not native to the region. Scientists say that kind of widespread damage is not expected from the European beaver in its natural habitat.