Q: In simple terms, how does carbon sequestration in natural systems work?
A. It begins with photosynthesis, the process by which green plants use light to split CO2 molecules that they draw from the air. The two oxygen molecules are released back into the atmosphere and the plant uses the carbon atom, called the building block of life because all life contains it, to produce sugars, build plant tissues and participate in symbiotic relationships. All three processes are essential to sequestering carbon.
When plant roots die, some of the carbon they contain is converted into stable substances in the soil. Similarly, as above ground vegetation, like leaves, falls to the ground and decomposes, some of the carbon they contain is moved underground by soil organisms and is sequestered in a stable form.
But research over the past several decades has shown that the most important process for sequestering carbon is the plant sugars. Sometimes called “the liquid carbon pathway,” these sugars directly or indirectly feed a myriad of organisms in the soil community, especially a type of fungi called “mycorrhizal fungi.” These fungi attach to the most plant’s roots in a symbiotic relationship in which the plant trades sugar for water and essential mineral nutrients that the vast web of fungal filaments through bacterial symbioses can obtain more efficiently than the plant’s own roots.
The underground biomass in a healthy soil community can be many times greater by weight than the above-ground biomass, including the animals living on the surface. Through several processes going on in this soil community, primarily a process called humification, much of the carbon the plants have drawn from the atmosphere and converted to sugars is sequestered in very stable forms. Researchers examining carbon sequestered in the soils of the Great Plains of the U.S. have found that some is as much as 13,000 years old and is still there.
It is this liquid carbon pathway and the management to facilitate it that are the foundation of all the many co-benefits that are generated by the win/win CO2 ecosolutions we are advocating for sequestering CO2.
Q: Where do these co-benefits of sequestration come from?
A. As noted in the FAQ above, they largely flow from the management that increases the carbon in the soil.
Carbon forms a water stable soil matrix that loosens the soil structure, holds nutrients and acts as a sponge for water. This means that in heavy rainfall events, more of the water can soak into the ground and be absorbed by the soil carbon and not run off into watercourses carrying silt and agrichemicals with it. Preventing this surface runoff has a number of direct environmental and economic benefits including improved aquatic habitat, reduced costs for providing drinking water and greatly mitigating flooding.
The water absorbed by the soil carbon is released slowly as plants need it, enhancing their growth and greatly increasing their ability to deal with drought. Some of this slow release of water also recharges springs and water courses, helping all the organisms in the ecosystem.
These more fertile and productive high carbon soils support a more diverse plant community, which in turn supports more diverse fungal and animal communities. High biodiversity is a characteristic of healthy ecosystems and is a major reason healthy ecosystems produce a number of important environmental and economic benefits.
Finally, healthy soil communities improve crop and forage production, both in terms of quantity and nutritional quality. This is important in dealing with the looming crisis of food security.
Forests can also be important carbon sinks, but unlike the carbon sequestered in agricultural and rangeland soils, most of the carbon sequestered in forests is above ground and subject to rapid reintroduction into the atmosphere by forest fires or more slowly as trees die and decompose. The key to making forests dependable carbon sinks is to manage them to achieve maximum health and productivity and reduce the danger of catastrophic fire. Healthy forests provide a wide range of economic and environmental co-benefits in their own right.
Q: Why are these win/win solutions beneficial “on both sides of the CO2 emissions equation?”
A. Currently, poorly managed and degrading crop and rangelands and burning forests are significant sources of CO2 and other greenhouse gases. The essential first step in implementing the win/win solutions to deal with excess CO2 is to begin to restore ecosystem integrity and health. As this is done, by such things as planting cover crops to cover, protect and cool the soil and reduce erosion, which is a major source of greenhouse gas emissions, and through restoring forest health by thinning and other good management practices, these emissions from these lands slow and quickly stop. That in itself is a major accomplishment in dealing with atmospheric carbon loading and does not even take into account the many co-benefits that are generated by these efforts to restore ecosystem health and integrity.
Then, as these various carbon-sequestering forestry, agriculture and grazing practices begin to take hold, these lands start to pull CO2 out of the atmosphere and sequester it long term in the soils and plant biomass.
So, on one side of the equation, the win/win CO2 solutions approach reduces emissions from these lands and forests. On the other side, once ecosystem integrity and health begins to be restored these lands that had formerly been significant emitters of greenhouse gases become important natural “sinks.”
Q: What is the difference between sequestering a ton of carbon and removing a ton of CO2?
A. There is a significant difference because the carbon atom makes up only about 27% of the CO2molecule by weight. In sequestering CO2 in soil, we are really only talking about sequestering the carbon portion of the molecule. During photosynthesis a plant breaks the molecule apart, releases the two oxygen atoms and uses the carbon to make sugars and plant tissue, etc. Some of that carbon is sequestered in the soil. So a ton of carbon sequestered in soil represents more than a ton of CO2removed from the atmosphere. The conversion is easy. Because the carbon atom represents only 27% of the CO2 molecule by weight, one ton of carbon sequestered in the soil is the equivalent of removing 3.67 tons CO2 from the atmosphere. Similarly, removing 1 ton of CO2 from the atmosphere through sequestration in soils is putting .27 tons of carbon in the ground.
Q: What are “CO2 equivalents” and why are they important?
A. The notation CO2e, meaning “CO2 equivalents,” is often used in measuring greenhouse gases (GHG). While CO2 is by far the most common GHG it is not the only one. Two others, methane and nitrous oxide, along with fluorinated gases, make up by far most of the greenhouse gases. Each of these has a different warming potential and remain in the atmosphere for differing periods of time. Methane, for example, is about 25 times more effective at trapping heat than CO2. Nitrous oxide is almost 300 times more efficient pound for pound than CO2. That means, for example that in terms of global warming potential 25 times more CO2 must be removed to compensate for the same weight of methane. To keep things simple, GHG emissions are usually referred to as CO2 equivalents or “CO2e.” A good primer on all this is here.
Q: What are “net zero emissions” and “net negative emissions” and why are they important concepts?
A. These terms refer to offsets for CO2 and other greenhouse gases (GHGs) being put into the atmosphere. “Net zero emissions” means that an equivalent amount of CO2e is being removed for an amount that is being discharged into the atmosphere or that a projected increase in CO2 emissions above a baseline amount is avoided by any of a number of means. “Net negative emissions” means that more CO2 is being removed from the atmosphere than is being added. There are a number of ways this can be done, but sequestration in natural systems is by far the best all around approach. The goal of the international “4 per Thousand” agreement, for example, is to achieve global net zero emissions for a period of at least several decades. The Paris Accords calls for achieving net zero emissions by about 2050. An increasing number of climate scientists believe that it is essential to achieve net negative emissions levels even before the 2050 Paris Accord target for net zero emissions is achieved. Again, sequestration in soil and natural systems is the only economical, practical, proven and available strategy that can be scaled up rapidly enough to have any prospect of achieving net negative emissions in any reasonable time frame.
Q: How can the amount of carbon being sequestered in natural systems be measured?
A. To understand the answer to this question it is important to first understand that there are two different approaches to measuring atmospheric CO2 removal.
It is essential to have precise measurements of how much CO2 is being removed by what we call the “mechanical” approaches to reducing atmospheric carbon. These include removing CO2 from stack gas emission streams and building “air capture” machines whose only function is to pull CO2 out of the air to utilize it in an industrial process or sequester it by injecting it into deep geological formations. The only way to know that any of these approaches is actually working is to determine that CO2 is coming out at the end. The only way to determine the efficiency, and therefore the practicality, of a mechanical approach, is to calculate such things as the capital and operating costs per ton of CO2 removed and that obviously requires precise measurements.
Using enough soil samples from a particular piece of land and chemically analyzing them can determine with great precision how much carbon is sequestered in the soil of that parcel. Repeating these measurements over time can determine how much carbon is being added or lost. This is the approach that is used by scientists to help determine the potential for sequestering atmospheric carbon in natural systems. (Some of that research is highlighted here.) But it is not practical to perform this level of testing on every acre of the large land areas that would be managed to sequester significant amounts of atmospheric carbon.
Fortunately, for a couple of major reasons, it also is not necessary.
For one thing, unlike with a mechanical device, nature has proven over millions of years that the methods by which carbon is sequestered “works.” And we know enough about how this process works to be able to make good estimates for how much carbon would be sequestered annually in any system with the same general parameters of weather conditions, plant species, soil type, land management approaches, etc. All the land falling within these same general parameters will sequester about the same amount of carbon. An analogy with a “mechanical” device would be to build one that always works without fail and removes the same amount of carbon every hour it is in operation. If such a machine existed, all we would need to know is how many hours it has run to determine how much CO2 has been removed. We would not need to measure each ton coming out of the process.
The second major difference is that scientific research on sequestration rates shows that there is more than sufficient land area in the world to sequester the total annual human generated CO2 emissions if we apply the best proven management techniques to it. In other words, we can achieve “net zero emissions” (See the FAQ above for a discussion of this term.) If we want to be more conservative in our estimates of how much land would be required to achieve a CO2 emission reduction target, or if we want to achieve “net negative” emissions, we simply apply these management techniques to a larger portion of the available land.
Taking such a conservative approach and managing more land to also sequester maximum CO2 would not be expensive. These proven land management techniques that also sequester large amounts of atmospheric carbon are already being employed on millions of acres around the world solely for the many environmental and economic benefits they generate. Any benefit from sequestering this additional carbon is not included in the cost/benefit management decisions to adopt them and, therefore, this additional carbon is literally being sequestered for free.
But we also have additional tools to help us be increasingly confident in the accuracy of our estimate on how much atmospheric carbon is being sequestered in natural systems. These include ongoing research, improved data from satellites and other remote sensing sources, extensive mapping of the world’s soils, the potential to develop every more sophisticated and accurate soil sequestration models and others.
While the mechanism for measuring the carbon sequestered in natural systems requires a different approach, it can certainly be done with enough precision to validate this as a viable and verifiable strategy.
(For a more detailed discussion of this topic, see our policy and analysis brief, “Measuring the Amount of Carbon Captured in Natural Systems” posted here.
Q: What is the “cattle/methane mistake?“
A. All ruminant animals, domestic cattle and their cousins such as buffalo, goats, and antelope, produce methane as part of the process by which they digest the plant material they eat. Methane is considered to be about 25 times more potent at trapping heat in the atmosphere than CO2. As a result, some uninformed scientists and climate activists make the mistake of assuming that merely reducing grazing or eliminating eating meat is a simple way to slow global warming.
This reasoning is overly simplistic, faulty and uninformed on several levels.
First, it is important to realize that the mechanisms by which methane is added and removed from the atmosphere are not well understood. For example, for reasons that scientist can only speculate about, global methane levels stabilized from 1999 to 2006 and then started rising again. Part of this uncertainty about methane is the result of a poor understanding of how methane is removed naturally in the atmosphere, primarily through interaction with sunlight, water vapor, and hydroxyl radicals.
In addition, it is also important to note that active steps to control methane emissions have proven to be effective for a number of other sources. EPA reports that in the U.S., methane emissions declined by 16 percent between 1990 and 2016 largely due to better control of emissions from landfills and in the energy sector.
With respect to methane and livestock production, it must first be understood that not all livestock production has the same carbon/methane “footprint.” For example, cattle raised entirely on grass have a much smaller footprint than animals finished on grain in feedlots. This is because various stages of the growing, harvesting and transportation of that grain fed to cattle in these feedlots have their own carbon footprints and methods of disposing of feedlot waste can be a major source of methane emissions as well.
These are not contributing factors in finishing cattle on grass and make simply talking about the potential “climate impact of beef (or livestock) production” even more misleading. Research shows that, when properly managed, raising and finishing cattle on grass actually creates a methane sink. The simplest way of demonstrating this (though as explained below one that does not fully reflect the “real world”) is to use the CO2e offset method explained in the FAQ above. If properly managed and healthy grasslands pull more than enough CO2 from the atmosphere to compensate for the warming effect of the methane the cattle grazing on that land produce then these grasslands are a net greenhouse gases (GHG) sink. The size of that sink is determined by how much additional CO2 is pulled from the atmosphere beyond that required to offset the methane emissions from the cattle. As noted in the examples of research posted on this site, that additional amount of CO2 sequestered can be substantial.
But in the “real world,” there are other ways that proper livestock grazing also compensates for methane production. One is through the improvement of forage quality that is a co-benefit of properly managed grazing. Higher quality forage generates less methane than lower quality forage.
It is also important to note that in the real world very significant amounts of the methane ruminants produce is actually eaten by “methanotrophic bacteria” that live in soils. The levels of these bacteria are heavily dependent on soil conditions and healthy rangeland soils will contain high levels of them. While the total potential of these bacteria to consume methane has not been thoroughly researched, it is known that they directly consume substantial amounts of the methane (and some experts think it may be all of it) emitted by livestock (or any other source), significantly reducing the amount that otherwise would have to be compensated for by sequestering CO2e as in the simple equation above. That, of course, makes healthy, grazed rangelands even more efficient GHG sinks in the real world.
Healthy rangelands also produce more water vapor from plant transpiration. As noted above, water vapor and sunlight are essential components in the most significant atmospheric chemical process for removing methane.
Finally, it is critical in the debate over livestock and methane to recognize that research has shown that the appropriate use of livestock is an essential element in most efficiently sequestering the greatest amount of carbon in rangeland and agricultural soils. Grazing lands and grazing animals evolved together and are interdependent. Proper grazing is essential to healthy rangelands. The Great Plains of North America, for example, contained the richest soils in the world and still have vast amounts of carbon sequestered in them. Analysis shows that some of this carbon was deposited thousands of years ago. The Great Plains were literally created over thousands of years by the grazing of countless millions of bison, elk, antelope, and deer. Grazing cattle in ways that mimic these wild herds can achieve equal results and on a much shorter timescale because of our improved understanding of how the process of soil sequestration works. From just a climate point of view, using this forage for grazing and consequently sequestering vast amounts of atmospheric carbon is far preferable to burning it, something that is happening naturally or being done intentionally on millions and millions of acres around the world every year.
In addition to being a critical tool in effectively sequestering CO2, the meat and dairy products that are produced are important elements in contributing to food security, also one of the goals of the Paris Accords. In the face of UN estimates that the world will need to produce 50% more food by 2050 just to keep up with population growth, this is a significant consideration as well.
The bottom line is that methane emissions are not a concern with grass finished cattle and other livestock properly grazed on healthy rangeland and pastures. In fact, this approach creates methane sinks, Even if this was not the case, the U.S. experience in reducing methane levels proves that there are other, better and more logical ways to deal with methane emissions than simplemindedly calling for elimination or reduction in livestock production. Properly done, livestock grazing can help produce many co-benefits in addition to sequestering atmospheric carbon that these other control strategies cannot. All of them should be applied first.
Like the world itself, the issue of livestock grazing and climate is much more complicated than it is often characterized to be and ignoring these facts and realities is a huge mistake.
Q: How do the win/win solutions improve food security?
A. Food security is becoming a significant and growing global problem and, while there are several major causes, the major culprits are deteriorating agricultural soils and some facets of “industrial agriculture” that are not sustainable. A high ranking UN official recently estimated that the world has less than 60 harvests left using current production methods and given the rate of deterioration of agricultural soils around the world. Adding to this coming crisis is the fact that the UN estimates that the world will need to produce 50% more food by 2050 just to keep pace with population growth.
The win/win solutions approaches not only stop the decline of soil productivity but reverse it, greatly increasing soil fertility. This means much higher production of crops and forage for livestock. The increased carbon content in the soils that is the result of sequestering atmospheric carbon also increases the resiliency of these lands to drought. Finally, since agrichemicals are virtually eliminated, profitability increases along with food security and nutritional density.
Q: How will the win/win solutions approach improve the lives of rural people?
A. Rural people, especially those in the developing nations of the world, are the most likely to be harmed by food insecurity. Experience with implementing these approaches and improving the availability and dependability of food shows that this not only improves their overall health and nutrition but the higher crop and livestock yields and the lower input costs of reducing or eliminating agrichemicals means higher profits that they can invest in a number of ways to improve their lives.
At the same time, the rural people living on the land are usually the ones who also are most impacted by deteriorating environmental quality. Since the mechanisms to sequester significant carbon in soils and natural systems requires the restoration of ecosystem health and productivity, these rural residents will see most of the co-benefits that are generated in this process.
Q: Why are these win/win solutions not being more widely adopted?
A. There are a number of reasons, but we think there are three principle ones. The first is that because there is not a lot of obvious money to be made if this solution is adopted as the primary strategy for dealing with CO2 there are no well-funded groups lobbying for it as there are for the mechanical alternatives. There is a lot of money to be made in researching, designing, manufacturing and installing these mechanical alternatives such pulling CO2 out of power plant emissions or creating “air capture” devices that would pull CO2 directly out of the air and dispose of or use it in some way (something, we cannot resist saying, that plants have been doing for millions of years for free). As a result, those who have a financial stake push for policies that emphasize and fund those approaches that would benefit them financially. Even worse, some special interests that would lose markets and profits if these win/win solutions are adopted actively work against them.
Very few members of the media are aware of this win/win approach either, so it gets little publicity.
As a result, too many policymakers and concerned citizens are not aware of this alternative approach and the many co-benefits that it generates. While some policymakers support the expensive mechanical approaches for a number of reasons, many elected officials would be supportive if they understood these many advantages. For many of the others, pressure from informed and concerned citizens would convince them to support them.
It is the primary mission of Win/Win CO2 Solutions Group to help inform the media, policymakers and concerned citizens of the many advantages of the win/win approach to dealing with CO2 and advocate for policies that incorporate them.
Please help us spread the word about the many win/win/win benefits of this approach to dealing with excess CO2 making a generous contribution
There are no big, well funded and well-organized groups pushing for this approach because they do not stand to make the huge profits they will with the mechanical alternatives to dealing with CO2 that they are pushing. So, if this win/win approach is to become the first policy choice for dealing with excess CO2 it is up to people like you to help make it happen. You can easily and securely donate to support our efforts here.