Sinking trees in Arctic Ocean could remove 1 billion tonnes of CO2
Cutting down boreal forest and sinking the felled trees in the depths of the Arctic Ocean could remove up to 1 billion tonnes of carbon dioxide from the atmosphere each year – but it could come at a cost to the Arctic ecosystem
Trees floating towards the Arctic Ocean
Carl Christoph Stadie/The Alfred Wegener Institute
Cutting down swathes of boreal forest and sinking the trees into the depths of the Arctic Ocean could remove up to 1 billion tonnes of carbon dioxide from the atmosphere each year.
Coniferous trees prone to wildfires could be felled and carried to the ocean by six major Arctic rivers including the Yukon and Mackenzie, where they would sink in about a year, according to a team of researchers.
“There is now a forest that is sequestering lots of carbon, but now the next thing is how to store it in a way that won’t get burned,” says Ulf Büntgen at the University of Cambridge.
Humanity will need to find ways to remove carbon dioxide from the atmosphere to compensate for industries that are hard to electrify – or even to begin reducing atmospheric CO2 levels. Direct air capture machines are expensive, however, and planting trees can backfire if they die or burn.
Several companies are burying wood, and US firm Running Tide sank 25,000 tonnes of wood chips off Iceland, although it was accused of endangering the environment and later shut down.
Up to 1 trillion tonnes of carbon are stored in wood, soils and peat in the boreal forest that stretches across northern Eurasia and North America, a number likely to rise as global warming accelerates plant growth. But more frequent and intense wildfires are increasingly releasing that carbon.
Büntgen and his colleagues previously found that wood had survived without rotting and releasing CO2 for 8000 years in cold, low-oxygen Alpine lakes. And the six Arctic rivers export huge amounts of logs, with beached driftwood in their deltas holding 20 million tonnes of carbon or more, estimates Carl Stadie at the Alfred Wegener Institute in Germany, who wasn’t involved in the new research.
If 30,000 square kilometres could be logged along each river each year – probably in winter when timber could be piled on the river ice – and then replanted, that growth could absorb 1 billion tonnes of CO2 annually, the researchers say.