Veni, Vidi, Vermi... I. On the contribution of Darwin’s ‘humble earthworm’ to soil health, pollution-free primary production, organic ‘waste’ management & atmospheric carbon capture for a safe and sustainable global climate.

Summary

Organic farming supplies more food with less ecological cost than chemical agriculture. Earthworm aspects of organic farming are twofold: ‘waste’ recycling through compost worms and soil enhancement from endemic field worms. Bio-physico-chemical benefits from sustained earthworm activity accrue for biodiversity, soil organic matter (SOM = worm-worked humus) derived from carbon sequestration of atmospheric CO2 via photosynthesis/humification and nitrogen N2 fixation from microbes rather than synthetic Haber-Bosch urea, plus greatly improved infiltration and soil-water-storage.
Just as earthworm burrows filter all rainwater, all atmospheric carbon from leaf litter/roots is processed through their intestines in 12 yr cycles as they build topsoil. Earth’s total soil data are not readily available, but flat-surface estimates with ranges of 2,400-6,020 Gt of topsoil humus are newly recalculated herein as 10,800-27,090 Gt containing 6,264-15,712 Gt SOC with a median value >10,000 Gt global soil carbon. Carbon restoration in this humus resource alone has potential for rapid reduction of Mauna Loa’s 400 ppm atmospheric CO2 by ~100 ppm, i.e., to pre-industrial levels.
This review highlights that organic husbandry – with earthworms at its core – offsets CO2 emissions (remediation) while moisture, pH, and soil temperatures simultaneously improve, increasing crop resilience and biodiversity (mitigation & adaptation). Earthworms naturally monitor & maintain healthy soils thereby solving human-generated climate & critical species extinction problems at both local & global scale. Such important considerations support 2015 Paris COP21 ‘Climate Change Policy’ agenda & international “4/1000 Initiative: Soils for Food Security & Climate”.