As the planet warms, soil releases more carbon dioxide, which further warms the planet—a vicious cycle. But why does heating soil result in more emissions? It was thought the increased temperature boosted the metabolisms of detritus-eaters, such as worms, insects and microbes, meaning they ate and breathed more.
But a four-year study of the soil of the cold boreal forests of North America, published in Nature Climate Change, showed that heating the soil 1.7°C or 3.4°C didn’t make a difference to the appetites of detritivores. In drought conditions, feeding decreased by 14 per cent.
So why does hot, dry boreal soil produce more carbon dioxide than when it’s cold? Study author Madhav Thakur suspects this is due to plant respiration—the breathing of their roots and their resident microbes.