Soil Organic Matter – the Most Critical Cause and Solution to Climate Change

Soil Organic Matter – the Most Critical Cause and Solution to Climate Change

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The current mainstream narrative is that climate change is caused by carbon dioxide (CO2) emissions from fossil fuels and methane emissions from farm animals. The solution is to reduce fossil use, scale up renewable energy, and eat less, preferably no, meat. I have shown why these ‘solutions’ will not stop climate change in previous articles.

-The Failure of Industrial Climate Solutions

-Response to Criticisms of Regenerative Grazing

-Regenerating Nature-based Systems – The Solution to Cooling the Climate

Skeptics claim there is no evidence that CO2 can cause climate change. Scientists have researched how CO2 drives atmospheric energy increases. NASA launched the IRIS satellite in 1970 to measure infrared radiation. Infrared is part of the spectrum of solar radiation that makes heat. The Japanese Space Agency launched the IMG satellite in 1996, which recorded similar observations. The data found decreased radiation returning to space at the infrared wavelength bands where CO2 absorbs energy. This radiation was being reflected and absorbed across the atmosphere. The measurements were direct evidence that proved the increase in heat and energy absorbed and radiated by CO2. 1

Subsequent research using more recent satellite data has confirmed these results. Since 1750, the start of the Industrial Revolution, this has added an extra 4.1 W/m² (watts per square meter) of energy to the atmosphere. Two thousand ninety-one trillion watts of energy have been added to the Earth’s atmosphere and oceans since 1750. This is the equivalent of the energy of millions of atomic bombs affecting our weather. This extra energy is violently fueling and disrupting our weather systems. It is causing weather events to be far more intense. Winter storms can become colder and be pushed further south and north than usual due to this energy, bringing damaging snowstorms and intense floods. Summer storms, especially hurricanes, tornadoes, tropical lows, etc., are far more intense, with increases in deluging destructive rainfall and floods. Droughts and heat waves are more common, resulting in more crop failures. They are also fueling damaging forest and grass fires that are burning out whole communities and changing regional ecologies due to not allowing time for recovery before subsequent fires.

Scientists assume that most of the increase in CO2 from 278 ppm in 1750 to over 427 ppm in 2024 comes from burning fossil fuels and cement production, with a small proportion from deforestation and nothing from the loss of soil organic matter. Research shows that this approach is highly problematic.

A study published by Skrable, Chabot, and French analyzed the change in the proportions of carbon-14 (C-14) in the atmosphere and disproved that the increase in CO2 is mainly the result of burning fossil fuels. All living organisms absorb C-14. It decays over time and disappears after 45,000 years. Its decay rate is used to date artifacts in archeology, paleontology, and many other sciences. Fossil fuels are so old that they do not have C-14. Consequently, the authors of this study could use it to determine the percentage of fossil fuel-based CO2 in the air from the beginning of the Industrial Revolution. 2

“Our results show that the percentage of the total CO2 due to the use of fossil fuels from 1750 to 2018 increased from 0 percent in 1750 to 12 percent in 2018, much too low to be the cause of global warming,”.

The research shows that a large percentage of the increase in CO2 in the atmosphere since 1750, from 280 ppm to over 400 ppm, comes from living carbon sources, not fossil fuels. These sources are obviously from clearing forests and soil organic matter (SOM) loss. 1.5 billion hectares (3.7 billion acres) of forest have been cleared since 1750, the beginning of the Industrial Revolution. That’s an area 1.5 times the size of the United States. This loss of forests has made, and continues to make, a massive contribution to the current CO2 levels. These forests played an essential role in removing CO2 through photosynthesis. Not only has this removal capacity been lost, but all the biomass was oxidized into CO2 and released into the atmosphere. Clearing these ecosystems also results in huge losses of SOM that are oxidized into CO2.

Soil organic matter (SOM) is the largest carbon pool after the oceans. Soil holds almost three times as much carbon as the atmosphere and forests combined. Degenerative land use is oxidizing this SOM into CO2. Despite being the second largest planetary carbon pool, SOM’s contribution to atmospheric greenhouse gases has not been included in current models used to calculate emissions. Oxidation of SOM is caused by excessive tillage, bare soil, and erosion. Synthetic nitrogen fertilizers stimulate the microbes that consume SOM and turn it into CO2. Research shows that they make considerable contributions to the CO2 in the atmosphere.

It is impossible to determine the amount of CO2 that has come from the extensive loss of SOM that started with the rapid expansion of broad-acre agriculture to supply the commodities for the Industrial Revolution due to a lack of records of the original levels of SOM. Ronnie Cummins and I give a conservative estimate in The Regenerative Agriculture Solution from the USA and Australia. Both countries had large areas of uncultivated land at the start of the Industrial Revolution, which became some of the first large industrial farms. There were records of the original SOM levels. Based on the current average SOM levels, we conservatively estimated that the United States and Australia alone are responsible for 660 billion tons (Gt) of atmospheric CO2 from the loss of SOM. This shows that thousands of Gt of CO2 have been lost from the soil and ended up in the atmosphere worldwide. 1

Researchers analyzed the results of a 50-year agricultural trial. They found that applying synthetic nitrogen fertilizer had resulted in all the carbon residues from the crop disappearing and an average loss of around 10,000 kg of soil organic carbon per hectare (10,000 Lbs per acre). It equates to emissions of 36,700 kg of CO2 per hectare (36,700 Lbs per acre) over and above the many thousands of pounds of crop residue that oxidizes into CO2 yearly. Multiple researchers have found that the higher the application of synthetic nitrogen fertilizer, the greater the amount of SOM lost as CO2. 3,4,5

A simple back-of-the-envelope calculation (see Appendix) extrapolating this on 90% of croplands shows that conservatively, 51 Gt of CO2 is emitted into the atmosphere yearly by the oxidation of SOM. This is the largest source of CO2, more than fossil fuels, and is not accounted for in the models or climate change negotiations.

The Global Carbon Budget is the primary document scientists, governments, and the UN use to quantify significant components of carbon emissions and sinks and their uncertainties. It describes and synthesizes data sets and methodologies from various climate scientists, research institutions, and governments. It uses statistics, production data, numerous models, assumptions, and estimations. 6

In 2022, they estimated that total anthropogenic CO2 emissions were 40.7 Gt. Emissions from clearing forests and associated land use were 4.7 Gt. Fossil fuel and cement emissions were 36 Gt or 88%.

The Global Carbon Budget gives estimates of the ocean and land sinks that remove CO2. The ocean sink removed 10.6 Gt, 26 % of total CO2 emissions. The land CO2 sink removed 12.1 Gt, 31 % of total CO2 emissions. All the other sinks were considered so negligible that they were not worth including. They calculated that the sinks removed 57% of emissions, and the rest, 17.5 Gt, went into the atmosphere. The average measurements of the atmospheric levels of CO2 showed it had increased by 19 GT in 2022, 1.5 Gt more than the 17.5 GT estimation.

The Global Carbon Budget does not balance. The authors saw this one-and-a-half billion-ton discrepancy as a minor issue. They gave the following reasons for this imbalance: ‘Comparison of estimates from multiple approaches and observations shows the following: (1) a persistent large uncertainty in the estimate of land-use changes emissions, (2) a low agreement between the different methods on the magnitude of the land CO2 flux in the northern extra-tropics, and (3) a discrepancy between the different methods on the strength of the ocean sink over the last decade.’

The methodologies, models, and assumptions used to inform them must be seriously questioned. Critically, living sources of emissions and sinks are seriously underrepresented in the models. A 2023 study published in Nature compared 11 marine biogeochemical models used to determine the amount of CO2 absorbed by the oceans by phytoplankton. The researchers found the level of uncertainty was over three times larger, calling into question the accuracy of 10.6 Gt used by the Global Carbon Budget. 7

Detailed research analyzing forests at a spatial resolution of 30 meters globally, published in Nature Climate Change in 2021, shows that forests remove 15.6 Gt of CO2 yearly compared to the Global Carbon Budget estimate of 12.1 Gt. Clearing forests and other disturbances emitted 8.1 Gt compared to the Global Carbon Budget estimate of 4.7 Gt. 8

The Global Carbon Budget models state that  88% of anthropogenic CO2 emissions come from fossil fuels and cement production, sources that do not have C-14 levels. The Skrable, Chabot, and  French study shows that 88% of the increase in CO2 since 1750 comes from sources with C-14. These are living sources, mostly from clearing ecosystems and the oxidation of soil organic matter.

Ignoring soil organic matter, the planet’s second-largest pool of carbon, as a significant source and sink for CO2 is a glaring oversight. The figures for the CO2 absorbed by forests do not account for the carbon they secrete into the soil.

Depending on the species, root exudates can distribute 10% to 40%, with an average of 30% of the CO2 captured by photosynthesis into the soil while the plants grow. The carbon compounds from root exudates penetrate deeper into the soils due to the depths of the roots than above-ground or tilled biomass. Deeper root exudates build SOM that is more durable and stable. 9, 10

Forest root exudates could amount to an extra 5 GT of CO2 removed annually, for a total of more than 20 Gt removed by forests.

Clearing 1.5 billion hectares (3.7 billion acres) of forest since the beginning of the Industrial Revolution and converting them into industrial agriculture has resulted in a massive decline in

SOM and considerable increases in atmospheric CO2. Agriculture, forest, and biodiversity management must change.

However, the most significant contributor to the current record levels of CO2 is the loss of soil organic matter through industrial agriculture. Historically, it has contributed thousands of gigatons, and currently, a conservative estimate of 51 Gt annually shows that it is a much higher source than fossil fuel emissions.

We must stop clearing ecosystems and start regenerating forests and pastures, end the use of synthetic nitrogen fertilizers, and adopt regenerative agriculture systems. This will stop the largest sources of CO2 and remove enough emissions to reverse climate change.

The following article in this series will explain how we can easily do this for a fraction of the trillions of dollars wasted on ineffective climate change mismanagement. 1, 10

Appendix for Calculations

United Nations Food and Agriculture Organization (UNFAO) has estimated that the land use:

  • Arable cropland: 1,396,374,300 hectares (3,490,935,750 acres)
  • Permanent crops: 153,733,800 hectares (384,334,500 acres)

Total 1,550,108,100 hectares
90% of this uses synthetic nitrogen fertilizers = 1,395,097,290 x 36,700 kg of CO2 per hectare = 51,200,070,543 kg

This means a conservative estimate of 51 billion tons (Gt) of CO2 are emitted into the atmosphere yearly by industrial agriculture’s oxidation of soil organic matter. This is the largest source of CO2 and is not accounted for in the models or climate change negotiations.

References

  1. Ronnie Cummins and André Leu, The Regenerative Agriculture Solution: A Revolutionary Approach to Building Soil, Creating Climate Resilience and Supporting Human and Planetary Health, Chelsea Green, September 2024
  2. Kenneth Skrable, George Chabot, and Clayton French, World Atmospheric CO2, Its 14C Specific Activity, Non-fossil Component, Anthropogenic Fossil Component, and Emissions (1750–2018), Health Physics 122,no. 2 (February 2022): 291–305,
  3. Khan, S.A., R.L. Mulvaney, T.R. Ellsworth, and C.W. Boast. 2007. The myth of nitrogen fertilization for soil carbon sequestration. Journal of Environmental Quality 36:1821-1832.
  4. Mulvaney, R.L., S.A., Khan, and T.R. Ellsworth. 2009. Synthetic nitrogen fertilizers deplete soil nitrogen: A global dilemma for sustainable cereal production. Journal of Environmental Quality 38:2295-2314.
  5. Man, M., B. Deen, K.E. Dunfield, C.Wagner-Riddle, and M.J. Simpson. 2021.Altered soil organic matter composition and degradation after a decade of nitrogen fertilization in a temperate agroecosystem. Agriculture, Ecosystems & Environment 310:107305.
  6. Friedlingstein, P., O’Sullivan, M., Jones, M. W., Andrew, R. M., Bakker, D. C. E., Hauck, J., Landschützer, P., Le Quéré, C., Luijkx, I. T., Peters, G. P., Peters, W., Pongratz, J., Schwingshackl, C., Sitch, S., Canadell, J. G., Ciais, P., Jackson, R. B., Alin, S. R., Anthoni, P., Barbero, L., Bates, N. R., Becker, M., Bellouin, N., Decharme, B., Bopp, L., Brasika, I. B. M., Cadule, P., Chamberlain, M. A., Chandra, N., Chau, T.-T.-T., Chevallier, F., Chini, L. P., Cronin, M., Dou, X., Enyo, K., Evans, W., Falk, S., Feely, R. A., Feng, L., Ford, D. J., Gasser, T., Ghattas, J., Gkritzalis, T., Grassi, G., Gregor, L., Gruber, N., Gürses, Ö., Harris, I., Hefner, M., Heinke, J., Houghton, R. A., Hurtt, G. C., Iida, Y., Ilyina, T., Jacobson, A. R., Jain, A., Jarníková, T., Jersild, A., Jiang, F., Jin, Z., Joos, F., Kato, E., Keeling, R. F., Kennedy, D., Klein Goldewijk, K., Knauer, J., Korsbakken, J. I., Körtzinger, A., Lan, X., Lefèvre, N., Li, H., Liu, J., Liu, Z., Ma, L., Marland, G., Mayot, N., McGuire, P. C., McKinley, G. A., Meyer, G., Morgan, E. J., Munro, D. R., Nakaoka, S.-I., Niwa, Y., O’Brien, K. M., Olsen, A., Omar, A. M., Ono, T., Paulsen, M., Pierrot, D., Pocock, K., Poulter, B., Powis, C. M., Rehder, G., Resplandy, L., Robertson, E., Rödenbeck, C., Rosan, T. M., Schwinger, J., Séférian, R., Smallman, T. L., Smith, S. M., Sospedra-Alfonso, R., Sun, Q., Sutton, A. J., Sweeney, C., Takao, S., Tans, P. P., Tian, H., Tilbrook, B., Tsujino, H., Tubiello, F., van der Werf, G. R., van Ooijen, E., Wanninkhof, R., Watanabe, M., Wimart-Rousseau, C., Yang, D., Yang, X., Yuan, W., Yue, X., Zaehle, S., Zeng, J., and Zheng, B.: Global Carbon Budget 2023, Earth Syst. Sci. Data, 15, 5301–5369
  7. Rohr, T., Richardson, A.J., Lenton, A. et al. Zooplankton grazing is the largest source of uncertainty for marine carbon cycling in CMIP6 models. Nature, Communications Earth and Environment, 4, 212 (2023).
  8. Harris, N.L., Gibbs, D.A., Baccini, A. et al. Global maps of twenty-first century forest carbon fluxes. Nat. Clim. Chang. 11, 234–240 (2021).
  9. Verma S and Verma A, Plant Root Exudate Analysis, in PHYTOMICROBIOME INTERACTIONS AND SUSTAINABLE AGRICULTURE, Editor(s): Verma A, Saini JK, Hesham A and Singh HB, John Wiley & Sons Ltd 2021, Print ISBN:9781119644620, Online ISBN:9781119644798
  10. Leu André, GROWING LIFE, REGENERATING FARMING AND RANCHING, Acres USA, Greeley Colorado, USA, December 2021