milky way across snow capped mountains

Obsession with top down

Sometimes you read a well-meaning research article and all is well until, boom, it hits you. The authors are from somewhere beyond the Orion nebula, over 1,300 light years away. Here is evidence that the aliens have landed…

Humanity will collapse or not depending on how we look after soil. 

This is the sustainably FED conclusion from decades of our research and advisory work and, as we hope this website attests, a reasonable understanding of the science behind feeding everyone well.

It will be possible to grow food in vertical gardens, make burgers from algae, and farm without fossil fuels, so there is a possible future where humans can persist without soil (assuming there are fewer people than today). The challenge is getting to that future in one piece, which means for at least another 50 to 100 years, global soils must be the source of most human food.

Presently global soils are in poor shape. 

When natural vegetation is cleared to grow crops or rear livestock, the soil is exposed, disturbed, and its biology disrupted. This is fine for a while as minerals are released and soil organic matter exchanges nutrients with the roots of crop plants. But exposure is terrible for the retention of organic matter and between 50 to 70% is lost within a few years forcing farmers to add inputs to maintain yield or even avoid crop failure.

After a few decades of use most agricultural soils are below optimum capacity to produce food because their capability is compromised—the FAO estimates that 40% are far enough below the optimum to be called degraded.

This is not fiction. 

All farmers, big and small, know this to be true from experience. They know that healthy soil is essential and that soil can get sick. Each farmer tries their best to look after soil health.

Science research is just as sure. 

Observational data catalogue the loss consistently, and experimental comparisons with undisturbed soils back up loss rates. Then there is detailed research on how and why soil carbon declines when soil is exposed and ploughed. The details you can see in our sustainably FED primer on soil organic carbon and our post on the soil carbon debt

Globally the current estimate is that land-use change and soil cultivation have contributed roughly 136 gigatons of carbon (Gt C) to the atmosphere from a change in biomass carbon since the beginning of the Industrial Revolution, with depletion of soil organic carbon (SOC) accounting for a further contribution of 78 Gt C.

Annual global carbon emissions from fossil fuel use (some of it in agriculture) is 10 Gt C and the amount of carbon dioxide in the atmosphere is 874 Gt C.

Peruse these numbers for a second.

What springs to mind? 

Maybe something like this 

  • 136 is roughly 16% of the current atmospheric carbon
  • add the 78 from soil carbon losses, and we are at 24%
  • each year another 1% is added to the atmosphere from fossil fuels, 10% per decade

You might also conclude that climate change is no surprise given what human activities have done and continue to do at a global scale. We are messing with more than the soil.

eroded soil on a gentle slope
Photo by Nima Mot on Unsplash

Sidenote | the carbon numbers in this post are expressed in tons of carbon (tC), whereas most climate information is expressed in tons of carbon dioxide equivalents (tCO2e). The conversion of tC to tCO2 is multiplied by 3.67, the ratio of the molecular weight of carbon dioxide to that of carbon (44/12).

The loss opportunity

Those with optimistic eyes will also see an opportunity in these soil loss numbers.

Suppose land management for agriculture has released so much carbon from the original vegetation that held on to way more. In that case, possibly, management could change and return some of that carbon.

Well, this is true. 

The science shows that it is possible to manage for carbon sequestration in agricultural lands both through vegetation and through soil organic carbon.

Science also tells us that this sequestration is suitable for climate mitigation in two ways. Sequestering organic carbon in the soil to repay the soil carbon debt could remove between 0.79 and 1.54 Gt C per year from the atmosphere. If super-optimistic like the FAO, then the potential at 2.45 Gt C per year, more than the yearly CO2 emissions from the aviation sector.  

Compliance and voluntary carbon markets present a means for farmers to generate carbon credits from carbon sequestration into the soil. As of 2017, fewer than 60 registered projects address soil organic carbon in croplands, pasture, peatlands or wetlands compared to 1,500 projects covering 12 million ha of land in the forest sector.

Opportunists still see the glass half full given these details. Meanwhile, the pragmatic among us see reasons that soil sequestration is late to the party.

Who is serious about soil organic carbon?

Not that many, at least in the carbon markets mechanism that is expected to reduce and offset carbon emissions. 

Fewer than 60 projects (half of them in Australia) that address soil organic carbon in croplands, pasture, peatlands or wetlands are currently registered under compliance or voluntary carbon markets, providing under 50,000 tCO2e in removals per year globally—nothing compared to 1,500 projects covering 12 m hectares of land in the forest sector.

People can see trees, so they feel more secure about them. Dirt is hard to see; what goes on in the dirt is a black box.

Perhaps the people entrusted with national policies on emission reduction are more serious. 

As of 31 March 2020, 186 parties (185 countries plus the European Union) had communicated their first Nationally Determined Contributions (NDCs) to the UNFCCC secretariat as per the Paris agreement. Only eight of these NDCs (4%) present targets for soil organic carbon within their intended mitigation options. A round of applause to Armenia, Burkina Faso, China, Japan, Malawi, Namibia, Uruguay and Zambia. 

Not sure what all the others were thinking.

Here are plenty of others with a stake in soil carbon.

infographic of the stakeholders in land management

Summary of the key stakeholders in changing land management practices

Source: Vermeulen, S., Bossio, D., Lehmann, J., Luu, P., Paustian, K., Webb, C., … & Warnken, M. (2019). A global agenda for collective action on soil carbon. Nature Sustainability, 2(1), 2-4.

The multitude of actors and the easy shift of responsibility hide a core challenge with soil carbon.

The narrative reads well for broad societal outcomes—double-digit increases in yield potential, particularly on degraded lands, higher household and national food security, reduced risks from disasters, improved water quality and lower rates of displacement and migration—but it is not society that must change practices. That task rests with the farmer. 

Farmers and land managers need a compelling value proposition because they take the risks and put in the extra effort to build soil organic carbon on top of already burdensome everyday management activities. A review by the Coalition on Agricultural Greenhouse Gases of on-farm soil projects in USA and Australia shows that ‘tradable carbon assets are unlikely alone to provide a strong value proposition on-farm’. 

A storyline around public good is not enough.

Farmers are practical folk, they need more than the promise of money from air.

Not least because soil carbon sequestration actions will cost them money. Here is a graph from a review of the costs of different carbon sequestration strategies (in 2012 US Dollars per tCO2e)

graph that shows the cost per tCO2e of different soil carbon sequestration tactics

Source: Tang, K., Kragt, M. E., Hailu, A., & Ma, C. (2016). Carbon farming economics: what have we learned?. Journal of environmental management, 172, 49-57.

What will it take to invest in soil carbon?

Several leading scientists in this field (see Vermeulen et al 2019 for an example) suggest that the value proposition for soil carbon has to meet five elements: 

  1. enhanced productivity, 
  2. improved risk management (for example, resilience to drought), 
  3. superior market access (for example, certified value chains), 
  4. financial returns to carbon assets, and 
  5. government support (for example, environmental subsidies)

These make good sense without resolving the farmer’s risk. He still has to take a punt that these elements will come together when he reduces tillage, avoids fertiliser use, keeps a cover crop or adds organic amendments to soils. Meanwhile, the forward contract for next season’s grain crop is just as hard-fought as ever.

Public gain, personal risk.

The scientists suggest a priority is to include soil organic carbon into existing international frameworks such as the UNCCD, UNFCCC, Ramsar and the Global Reporting Initiative.

And here we part company. 

International conventions and UN bodies are essential to keep the international dialogue going under the premise that it is best to keep everyone in one tent. But they tend to fail on the ground because the solutions they suggest are a million miles away from the farmer and her everyday decisions.

The cold reality is that anything top-down has failed because of the premise that top-down operates—the autonomy of individual choice.

Investing in soil carbon requires the farmer to decide it is the best and the right thing to do on his farm.

What sustainably FED suggests

We have always been wary of top-down edicts finding their way into decision-making within farm operations.

Big broad brushes with collective agendas rarely help the farmer. 

Remember that worldwide 500 million farmers only feed themselves and their families from their smallholder farms. These farms feed more than 2 billion people, including about 80 per cent of the food consumed in Asia and sub-Saharan Africa.

These farms are net energy producers but only just. Any change to tried and tested practices doesn’t risk profit margins, it risks livelihoods.

And we always remember what Albert Einstein so famously said: “We cannot solve our problems with the same thinking we used when we created them.”

Science sources

Amelung, W., Bossio, D., de Vries, W., Kögel-Knabner, I., Lehmann, J., Amundson, R., … & Chabbi, A. (2020). Towards a global-scale soil climate mitigation strategy. Nature communications, 11(1), 1-10.

Tang, K., Kragt, M. E., Hailu, A., & Ma, C. (2016). Carbon farming economics: what have we learned?. Journal of environmental management, 172, 49-57.

Vermeulen, S., Bossio, D., Lehmann, J., Luu, P., Paustian, K., Webb, C., … & Warnken, M. (2019). A global agenda for collective action on soil carbon. Nature Sustainability, 2(1), 2-4.

Hero image from photo by Benjamin Voros on Unsplash


Mark is an ecology nerd who was cursed with an entrepreneurial gene and a big picture view making him a rare beast, uncomfortable in the ivory towers and the disconnected silos of the public service. Despite this he has made it through a 40+ year career as a scientist and for some unknown reason still likes to read scientific papers.

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