Soils : The Missing Link In Carbon And Climate Change Conversations

With Skip Hyberg

If you pay attention to media coverage, you’ve probably seen numerous stories previewing the United Nations climate change meeting, formally known as COP26, that began Oct. 31 in Glasgow. More than 200 governments will work to reach agreement on a strategy to address climate change and make commitments to reduce greenhouse gas emissions. 

In the leadup to this meeting, many observers have noted that carbon emissions need to be reduced; that innovative technologies need to be developed; and that forest-focused activities such as protecting the Amazon rainforest and other established forests and planting 1 trillion more trees. 

Each of these ideas has merit. But how do we choose the correct approach? Most media coverage tends to focus on a single approach. It fails to mention the need to walk and chew gum at the same time. That is, we need to do multiple things to address climate change—including reducing net emissions, developing new technologies and using natural systems to sequester carbon.  

Understanding nature’s carbon-capturing capacity. Our primary objection to most public discussions of climate change is that they overlook the role of soils (and oceans) in reducing the emission of atmospheric greenhouse gases and regulating greenhouse gas concentrations. 
If you stop and think about it, you can identify three broad pools of carbon on Earth: 
1.    Active (short-term) carbon found in biological organisms, the atmosphere and oceans; 
2.    Intermediate carbon stored in soils and deep ocean deposits; and
3.    Inactive (long-term) carbon bound in mineral and petroleum deposits that has not been extracted.

Extraction of that long-term carbon and its release has contributed to the increase of carbon dioxide,  the dominant greenhouse gas, in the atmosphere. .
Soils and oceans link active and inactive carbon pools. They supply an environment for microbes, which take and process the carbon that plants capture from the atmosphere. If this carbon is left in soils, geological processes will eventually bind it in long-term storage in mineral, petroleum and coal deposits. Examples of this process in action include the permafrost in the arctic region and peat deposits found in more temperate regions. Bury these deposits, put them under pressure, wait millions of years and—voila—carbon is bound up in long-term mineral deposits.

Of greater interest to farmers is what the carbon does while it is in the soil. It improves soil health so that the soil is more productive, has better structure, can retain more water and nutrients, and is less prone to erosion. In short, increasing the carbon stored in soils makes agricultural operations on cropland, pastures and grazing land more resilient in a dynamic world. 

Stacked benefits of carbon sequestration. Let’s look at these effects one at time. Increased productivity means less land is needed to supply food to an expanding world population. At a time of more frequent and increasingly extreme weather events that damage crops and livestock, increasing the productivity of soils in the U.S. and abroad can only improve global food security. 

Improved soil structure and increased ability to retain soil water create greater resilience. Excess water will be able to drain through the soil when precipitation is high, and the soil will be able to hold moisture and make it available when precipitation is low. The result is that soil will provide more consistently beneficial growing conditions in the face of extreme weather. Finally, when soil is less prone to erosion your primary resource is protected and the productivity of your land is maintained. 

That’s all well and good for individual farmers. But how do these considerations help address climate change? Collectively, soils hold two to three times more carbon than the atmosphere. And agricultural soils have the capacity to store a substantially greater amount of carbon with proper management. 
Studies have estimated that the soil carbon content of U.S. cropland has decreased by as much as 50 percent since their conversion to agricultural use. This carbon was lost as the soils have been tilled over time. This tillage exposed stored carbon to oxidation, releasing carbon dioxide into the atmosphere. 
Conservation systems that reduce or eliminate tillage and retain crop residue can restore soil carbon that has been lost. But barriers to widespread adoption must be addressed, including equipment costs, social pressure, information deficiencies and the learning curve. 

Opportunities for farms and ranches. Any strategies addressing climate change should recognize the role natural systems must play in restoring carbon balances in long-term and short-term pools. 

Soils will be a necessary keystone of successful climate action because of their ability to capture and sequester carbon. We need to craft policies that recognize farmers who adopt soil management conservation systems to promote soil health as good stewards. We should help producers overcome barriers and reward them for addressing rising greenhouse gas emissions. 

We must also recognize the need for further resources. USDA’s Natural Resources Conservation Service (NRCS) offers conservation programs that help farmers overcome key barriers to voluntary adoption, but demand often exceeds available funding and technical support capacity. For example, between 2000 and 2010, only about 40 percent of projects proposed were approved for funding under the Environmental Quality Incentives Program (EQIP). America’s Conservation Ag Movement is an example of a social impact program bringing federal and private-sector resources to the fore to help farmers and ranchers on this journey. 

The time has come for conversations about climate change to recognize the importance of soil and the farmers and ranchers who steward it. Greater understanding of soil’s potential contribution to addressing climate change would lend itself to stronger support for policies that compensate farmers for adopting practices to increase soil carbon. 

Perhaps now is the opportunity for agriculture to make itself heard and emphasize the need to fully incorporate soil management into global climate-change strategies.