Earthworms play an essential part in determining the greenhouse-gas balance of soils worldwide, and their influence is expected to grow over the next decades. ~ Dutch soil scientist Ingrid Lubbers et al
Taiga is the Earth’s largest land biome, comprising 29% of the world’s forest cover. Boreal forest is a nearly continuous belt of coniferous trees across northern North America and Eurasia. At least 20% of the carbon that cycles through the world passes through taiga.
In the past, forests were the great terrestrial carbon sink. That is rapidly changing, as the carbon stored in soils is released.
Taiga has special soil. In warmer climates, the floor of a typical forest is a mix of minerals and organic soil. In a boreal forest, those components are distinct, with a thick layer of mosses, fallen wood, and rotting leaves on top of the mineral soil. The spongy organic layer holds most of the carbon stored in boreal soil.
As the world warms, earthworms have been migrating north into taiga, where these worms have been relatively scarce (compared to the soils in temperate forests). Most of the earthworms heading north are ones that eat leaf litter but don’t burrow into the soil.
Even though worms themselves are tiny and don’t individually seem to constitute a threat, considering how many of them there are, they’re very important organisms. ~ American soil scientist Adrian Wackett
The impact of invasive earthworms is expected to be intense: reducing forest floor carbon 50–94% over the next 4 decades, thereby accelerating global warming in a way that no current climate models anticipate.