They may look cute and harmless, but squirrels and beavers are contributing to climate change far more than previously thought, climate scientists have claimed. However, their discovery doesn’t let us humans off the hook, as the scientists still insist that carbon dioxide emissions are causing arctic permafrost to melt, compounding the squirrels’ efforts, the Daily Mail has reported.

According to researchers working on the Polaris Project in the Arctic, which aims to study climate change at the poles, arctic ground squirrels and beavers both contribute to carbon emissions by burrowing into the frozen soil to make their homes, churning up the soil. Faeces and urine from the rodents fertilises the soil, encouraging decomposition of biological material that had been locked in suspended animation by the frost, releasing greenhouse gases into the atmosphere.

Nigel Golden, an ecologist at the University of Wisconsin who took part in the project told the BBC that the ground temperature around the rodents’ burrows was higher than in the surrounding area. “’They are soil engineers,” he said. “They break down the soil when they are digging their burrows, they mix the top layer with the bottom layer, they are bringing oxygen to the soil and they are fertilizing the soil with their urine and their faeces.

“We saw an increase in soil temperature in the soils where the arctic ground squirrels were occupying. This is a major component. As that permafrost begins to warm, now microbes can have access to these previously frozen carbons that were in the soil. And because they mix the soil layers, they are being exposed to warmer temperatures.”

The arctic permafrost is estimated to hold twice as much carbon as is currently present in the Earth’s atmosphere. Climate scientists are therefore concerned that, if the frost melts, the carbon could be released, contributing to climate change. However, they concede that the squirrels are not able to melt the permafrost on their own. There is still a role for man in this climate catastrophe story.

“This is a larger story about wildlife impacts on carbon cycling, and how this may change as the climate warms,” said Dr Sue Natali, who led the Polaris Project.

“Human activities are the primary influence on climate. We do, however, need to understand how these activities are impacting natural ecosystems, and how these ecosystem responses will amplify or attenuate these human-driven impacts.

“Even though we cannot alter wildlife activity, it’s important that we include greenhouse gas emissions from these activities into our accounting of carbon loss from the Arctic.”

The squirrels are not the first animals to have been accused of contributing to climate change. The world’s 1.5 billion cows are thought to contribute as much as 14 percent of the world’s greenhouse gas emissions by releasing methane into the atmosphere. PETA claims that “a staggering 51 percent or more of global greenhouse-gas emissions are caused by animal agriculture,” citing a report by the Worldwatch Institute, and the UN has said that raising animals for food is “one of the top two or three most significant contributors to the most serious environmental problems, at every scale from local to global.”