Robert J. Blakemore

Soil, with 30,000 Gt SOC (Gigatonnes of Soil Organic Carbon), is the greatest global store of active carbon as well as being source and sink of most atmospheric CO2. Soil respiration/decay (~220 Gt C/yr) is twenty times Fossil Fuel (FF) emissions (~10 Gt C/yr). Soil supports >99.9% of species biodiversity (mainly microbes), provides ~99% of human food, and filters100% of our drinkable freshwater (via earthworm burrows). Soil is yet the most neglected biome as are its main monitors and mediators, the resident earthworms. These are silently dying, just as soil is being eroded and degraded at irreplaceable rates, to our, and all other species’, detriment. Land use changes (LUC) release carbon from deforestation and soil erosion/poisoning at rates about twice that of FF emissions, themselves twice the CO2 increase (5 Gt C/yr). Knowing all this provides a ready solution to Climate, to Food Security as well as the most pressing of issues: The rapid and irreversible species extinction. Based upon proper scientific context and urgent triage priority, the imperative is to redirect all our efforts and funding to restore topsoil. The simplest remedies, available to anyone, are to vermi-compost, to demand or support 100% organic food (thus protecting earthworms), and to reduce excess red-meat. In this way rich soil humus is revived, deforestation is reduced and toxic poisoning of our air, water, soil and food is resolved. Organic husbandry within broader Permaculture design principles allows practical and proven solutions to the ecologically interlinked problems.

More than a decade of research led to the conclusion in 2022 that the Soil Biome is home to ~ 2.1 × 10²⁴ taxa and thus supports > 99.9% of global species biodiversity, mostly Bacteria or other microbes, based upon topographic field data. A subsequent 2023 report tabulated a central value of just 1.04 × 10¹⁰ taxa claiming soils had 59 ± 15%, i.e., 44–74% (or truly 10–50%?) of the global total, while incidentally confirming upper values of ~ 90% for soil Bacteria. Incompatibility of these two studies is reviewed, supporting prior biodiversity data with the vast majority of species inhabiting soils, despite excluding viruses (now with ~ 5 × 10³¹ virions and 10²⁶ species most, ~ 80%, in soils). The status of Oligochaeta (earthworms) and other taxa marked “?” in the 2023 paper are clarified. Although biota totals are increased considerably, inordinate threats of topsoil erosion and poisoning yet pertain with finality of extinction. Species affected include Keystone taxa, especially earthworms and microbes, essential for a healthy Soil foundation to sustain the Tree-of-Life inhabiting the Earth.

Basic inventory is required for proper understanding and utilization of Earth’s natural resources, especially with increasing soil degradation and species loss. Soil carbon is newly refined at >30,000 Gt C (gigatonnes C), ten times above prior totals. Soil organic carbon (SOC) is up to 24,000 Gt C, plus plant stocks at ~2400 Gt C, both above- and below-ground, hold >99% of Earth’s biomass. On a topographic surface area of 25 Gha with mean 21 m depth, Soil has more organic carbon than all trees, seas, fossil fuels, or the Atmosphere combined. Soils are both the greatest biotic carbon store and the most active CO₂ source. Values are raised considerably. Disparity is due to lack of full soil depth survey, neglect of terrain, and other omissions. Herein, totals for mineral soils, Permafrost, and Peat (of all forms and ages), are determined to full depth (easily doubling shallow values), then raised for terrain that is ignored in all terrestrial models (doubling most values again), plus SOC in recalcitrant glomalin (+25%) and friable saprock (+26%). Additional factors include soil inorganic carbon (SIC some of biotic origin), aquatic sediments (SeOC), and dissolved fractions (DIC/DOC). Soil biota (e.g., forests, fungi, bacteria, and earthworms) are similarly upgraded. Primary productivity is confirmed at >220 Gt C/yr on land supported by Barrow’s “bounce” flux, C/O isotopes, glomalin, and Rubisco. Priority issues of species extinction, humic topsoil loss, and atmospheric CO₂ are remedied by SOC restoration and biomass recycling via (vermi-)compost for 100% organic husbandry under Permaculture principals, based upon the Scientific observation of Nature.

Soil carbon is newly refined as ~32,000 Gt C (gigatonnes) over ten times previous totals. Soil organic carbon (SOC) of ~22,000 Gt C plus plants at ~2,400 Gt C in both above- and below-ground stocks hold 99% of Earth’s biomass. Occupying a topographic surface area of 25 Gha with mean depth 21 m, soil has more organic carbon than all plants, oceans, fossil fuels, or the atmosphere combined. Soils are both the greatest biotic carbon store and the most active CO2 source. Basic inventory is required for proper understanding and utilization of Earth’s natural resources, especially with increasing soil degradation and species loss. Values are raised considerably, the disparity due to lack of full soil depth survey, neglect of terrain and of other omissions. Herein new totals are determined for mineral soils, permafrost, and peats (of all forms and ages), to full depth (easily doubling shallow values) and allowing for terrain that is ignored in all terrestrial models (doubling most values again), plus SOC in recalcitrant glomalins (~30%) and friable saprock (+26%). Additionally, soil inorganic carbon (SIC), aquatic sediments and dissolved fractions are factored in. Soil biota (e.g. fungi, bacteria and earthworms) are similarly upgraded. Primary productivity, also upped for terrain, is confirmed at 220 Gt C/yr on land supported by C/O isotope fluxes. Priority issues of species extinction, humic topsoil loss, and excess atmospheric CO2 are all remedied by SOC restoration and biomass recycling via (vermi-)compost for use in 100% organic husbandry and adoption of wider practices of Permaculture based upon scientific observation of Nature.

Recent dawning and the uptake expansion of rapid genomic sequencing has radically transformed our understanding of the biosphere, especially casting a new light in relation to soils. Williamson et al. (2017) concluded: “Soils represent the greatest reservoir of biodiversity on the planet; prokaryotic diversity in soils is estimated to be three orders of magnitude greater than in all other ecosystems combined.” In other words, soils may contain >99.9% of species, mainly microbes. Supporting this were, for example, Bickel & Or (2020) and Zhao et al (2022) who found: “soil is the most microbiologically abundant (10²⁹) and diverse (10¹¹) environment on the Earth” and, in their figure 3A, these latter authors showed soil taxa at >10× that of the ocean, i.e., >90% diversity in Soil vs Ocean. Independently, Blakemore (2022) estimated the Soil Realm is home to ~2.1 x 10²⁴ taxa supporting >99.9% of global species biodiversity, mostly Bacteria, Archaea or other microbes, based upon topographic extrapolation of field data.

A decade or so of research led to the conclusion, in 2022, that the Soil Realm is home to ~2.1 x 10²⁴ taxa and supports >99.9% of global species biodiversity, mostly Bacteria or other microbes based upon topographic field data. A subsequent 2023 soil biodiversity report tabulated a central value of just 1.04 × 10¹⁰ taxa and claimed soils had 59±15% (i.e., 44–74%) of total species on Earth, incidentally confirming upper values of ~90% for Bacteria. Incompatibility of these two studies is reviewed, supporting the prior global biodiversity data with a vast majority of species inhabiting soil, this despite excluding virus entities (now with >5 x 10³¹ virions and up to 10²⁶ species, 80–90% being in soils). The true status of Oligochaeta (earthworms) and other taxa marked “?” in the 2023 paper are clarified. Although soil biota totals are raised enormously, inordinate threats and the reality of species extinctions yet pertain, specifically to those biota – such as microbes and earthworms – essential for rich, healthy soils that house & nourish almost all the Tree of Life presently on Earth.

Land’s basic metric is soil organic carbon (SOC) yet global estimates range 1,417–15,000 Gt C. Erosion of ancient topsoil and loss of soil taxa are most urgent of all context-triage concerns, and most ignored. Re-evaluation of topographical terrain on a non-flat Earth increases most soil dynamic inventories. Carbon credits of our neglected and disappearing SOC stocks are enumerated for mineral soils (~4,100 Gt C plus ca. 20–30% glomalin), Permafrost (>4,200 Gt C), peat (1,123 Gt C), plant roots (916 Gt C), litter (600 Gt C), microbes (200 Gt C), fungi (30 Gt C), biocrust (10–20 Gt C), earthworms (2.3–3.6 Gt C), termites (0.15 Gt C), nematodes (0.06 Gt C), ants (0.024 Gt C), and soil viruses (0.02–4.0 Gt C). Net contribution to atmospheric CO2 is more from biotic topsoil loss (>10 Gt C/yr) than fossil fuels (<10 Gt C/yr). Although higher CO2 results in a terrestrial greening effect with Net Primary Productivity (NPP) now ~220 Gt C/yr (cf. ~20 Gt C/yr Ocean NPP), this is arguably offset by topsoil erosion, desert expansion, plus fire at net ~16–20 Gt C/yr lost due, in part, to extravagant meat-eating with unsupportable, humus-depleting farm management. In particular, excess synthetic Nitrogen acidifies topsoil and destroys the natural SOC biota. Review shows critical topsoil loss up to 20,000 tonnes per second and, when soil microbes/invertebrates are properly considered, extinctions as high as 23 taxa per second. Sustainable Development Goals (SDGs) fail without solid soil foundation. Rather, heritage farm-data points to resolution in organic husbandry. Remedy via natural vermi-compost, 100% organic farming and practical Permaculture is under a simple premise that the Problem (i.e., SOC loss) is the Solution (viz., SOC restoration).

This new study revised interlinked issues of global soil organic carbon (SOC), annual net primary productivity (NPP) and atmospheric CO₂ turnover time (τ). Soil is confirmed as both the greatest sink and source for excess atmospheric CO₂. Most terrestrial NPP (~218 Gt C/yr) is ultimately processed in topsoil and SOC stocks now total >10,000–12,000 Gt. More excess carbon is released into the air and water from SOC loss (>20 Gt C/yr) due to land clearance for pasture/crops, fires, agrichemical poisoning and erosion, than from fossil fuels (~10 Gt C/yr). NOAA’s Barrow bounce and isotopic analyses support high terrestrial flux up to ~800 Gt C/yr and CO₂ turnover time of ~1–4 years. Earth’s re-humification via compost offers the best and only practical/time-critical fix for climate, strategy for species extinction plus remedy for human health.

Shutdown for just six days enables land plants to entirely fix CO2 excess of +4 Gt C per yr. Rebuilding soil organic carbon (SOC) in worm-worked humus is the only practical carbon capture and storage (CCS) capable of freely offsetting annual anthropogenic emissions. A case is made to redirect all available resources towards proven, earthworm-based, organic husbandry. Priority is to safely combat mounting global threats due to irreversible species extinction, perilous climate change and deteriorating human wellbeing (mental/physical health). All three interlinked risks are underpinned by a relentless, yet largely ignored, critical loss of precious topsoil. A first step to topsoil recovery is vermi-composting all vegetable and animal ‘wastes’ for return to the field.

Earth’s land surface is raised from conventionally flat 15 Gha to >64 Gha accounting for hilly slope undulation and topsoil relief detail. Three main aspects are: topography, rugosity/tortuosity, and micro-relief/porosity of ice/vegetation-free ground. Recalibration arises from four approaches: First, direct empirical estimates of compiled satellite/LiDAR data means of +2.5–26% surface progressively overlain by +94% at cm² scale for soil ruggedness then +108% for mm² micro-relief; Second, from digital elevation models with thrice 1.6–2.0 times flat areas; Third, by ‘reverse engineering’ global soil bulk densities and carbon reserves requiring ×4–6 land. Finally, a Fermi estimation doubles the Earth’s surface—as exposed to Sun, air and rain—conveniently set at 100 Gha (with 64 Gha land:36 Gha ocean). Soil organic carbon (SOC) thereby grows to 8580 Gt mainly in SOM-humus with its biotic complexity plus roots, Vesicular-Arbuscular Mycorrhiza (VAM-fungi), leaf-litter and earthworms itself totaling 17,810 Gt. Although four to six times IPCC’s or NASA/NOAA’s calculated 1500–2300 Gt SOC, this is likely an underestimation. Global biomass and biodiversity are at least doubled (×2–3.5) and net primary productivity (NPP) increases to >270 Gt C yr⁻¹ due to terrain. Rationale for a ‘Soil Ecology Institute’ gains ground.