How Healthy Soil Can Help Stabilize Weather Patterns

To mitigate the most severe consequences of climate change, global initiatives like the Paris Agreement urge us to limit global temperature rise to less than 2°C above pre-industrial levels. While reducing emissions is critical, achieving this goal will likely also involve removing carbon dioxide (CO₂) from the atmosphere. Common approaches like planting forests or using advanced carbon capture technologies often come with challenges like high costs, land usage, or resource intensity.

An often overlooked but highly effective method is sequestering carbon in soil. This natural process offers a sustainable way to reduce atmospheric CO₂ while improving land productivity and stabilizing weather patterns.

Soil: A Massive Carbon Reservoir:

Earth’s soil stores some 2,500 gigatons of carbon—three times as much as the atmosphere and four times as much as living plants and animals—making the earth’s ability to store such a large amount of carbon an important tool in warfare against climate change.

“Considering the sheer size of the soil carbon pool, even small increases in its capacity can significantly affect climate stabilization,” explains soil ecologist Ben Taylor.

Healthy soil already removes about 25% of global fossil fuel emissions annually. This natural process helps moderate extreme weather, including heatwaves and intense storms, by reducing atmospheric CO₂ and its contribution to global warming.

How Carbon is Stored in Soil:

How much carbon soils can absorb and how long they can store it varies by location and is effectively determined by how the land is managed. Because almost half the land that can support plant life on Earth has been converted to croplands, pastures and rangelands, soils have actually lost 50 to 70 percent of the carbon they once held. This has contributed about a quarter of all the manmade global greenhouse gas emissions that are warming the planet.

Agricultural practices that disturb the soil—such as tilling, planting mono-crops, removing crop residue, excessive use of fertilizers and pesticides and over-grazing—expose the carbon in the soil to oxygen, allowing it to burn off into the atmosphere. Deforestation, thawing permafrost, and the draining of peatlands also cause soils to release carbon.

How soil stores carbon:

Through photosynthesis, plants absorb carbon dioxide from the atmosphere. Carbon is converted into leaves, stems, seeds and roots using water and sunlight. During respiration, plants release carbon dioxide back into the atmosphere and release carbon dioxide through their roots as an acidic substance. These effluents feed subsurface microorganisms (bacteria, fungi, protozoa and nematodes). When plants die, soil bacteria break down the carbon inside them and use it for metabolism and growth, and some are respired back into the atmosphere.

Because microbial decomposition releases carbon dioxide, the soil can store more carbon when it is protected from microbial activity. One key way that happens is through the formation of soil aggregates. This occurs when tiny particles of soil clump together, sheltering carbon particles inside them. Mycorrhizal fungi, which produce sticky compounds that facilitate soil aggregation, are able to transfer 15 percent more carbon into the soil than other microbes. Soils with high clay content are also able to form chemical bonds that protect carbon from microbes. These aggregates give soil its structure, which is essential for healthy plant growth.

Some carbon, made up mainly of plant residue and the carbon exuded by plant roots, remains in soil only for a few days to a few years. Microbes can easily digest this “fast pool” of carbon, so it emits a great deal of carbon dioxide. The “slow pool,” where carbon can remain for years to decades, is composed of processed plant material, microbial residue from the fast pool and carbon molecules that are protected from microbes. A third “stable pool,” comprised of humus—decomposed organic material—and soil carbon that is well protected from microbes, is found below one meter deep and can retain carbon for centuries to millennia.

Soils can sequester more carbon:

A 2017 study estimates that, if properly managed, the world’s cropland could store an additional 1.85 gigatons of carbon per year—the amount the global transportation industry emits annually and some scientists believes that soil can continue to store carbon for 20 to 40 years for many years before becoming saturated.

Most crops are annuals, so fields are generally empty after harvest. Agriculture can compensate for carbon losses by injecting more carbon into the soil by leaving crop residues in the soil or planting cover crops such as sesame seeds.

Crop rotation and the use of a variety of crops, particularly perennials with deeper roots, increase the amount of carbon in the soil by adding a wider range of biomass, some of which may be more resistant to breakdown.

When tillage is kept to a minimum, soil aggregates stay intact and their carbon is protected from oxygen exposure.

“By restoring the soil with natural sources of organics that support beneficial microbes that improve plant growth, the plants will flourish and draw down the carbon from the atmosphere,” O. Roger Anderson, a biologist at the Earth Institute’s Lamont-Doherty Earth Observatory, explained via email. “Theoretically the plants will grow at a more robust rate, drawing down CO2 more rapidly than the relatively lower emissions of CO2 that the metabolism of the microbes produce in a healthy soil ecosystem.”

What effects will climate change have on soils?

Since temperature and precipitation affect the distribution of organic matter and the amount of carbon in soils, how will climate change alter these carbon reservoirs?

According to new research, soils will release more carbon than previously believed as long as global warming persists. According to earlier research, soils heated 5 to 20 cm deep would emit 9 to 12 percent more carbon dioxide than usual. However, more than half of the world’s soil carbon is found in deeper soil layers, and scientists discovered that heating soils to a depth of 100 cm could cause them to release up to 37% more carbon dioxide than they normally would.

Studies show that there will be more carbon for microorganisms in the fast pool as rising atmospheric CO2 levels promote plant growth and the release of root exudates. This will increase CO2 respiration and microbial breakdown. Additionally, the microbial population may be “primed” to break down soil organic matter that might not otherwise be as readily available by the additional root secretions. According to some simulations, soils may transition from being a carbon sink to a source of carbon later this century as a result of increasing microbial respiration.

Furthermore, bacteria may actually emit more carbon over time, which would exacerbate global warming. Warming temperatures may cause periodic spikes in carbon dioxide emissions from soils, according to a 26-year study on soil warming in a hardwood forest. CO2 levels rose throughout the first ten years as bacteria in the heated plots broke down carbon and released it into the atmosphere. Levels then decreased and stayed constant over the following eight years, matching those of unheated plots.After that, CO2 emissions increased once more for five years before declining once more.
The scientists concluded that the community of microbes changed over the years. After the first wave of microbes that decomposed the easily digestible carbon died off, a new set of microbes evolved that were able to decompose more resistant carbon that contains more minerals or is wood-based. Most global warming studies only calculate the initial rise in carbon emissions; this research suggests that microbes will evolve, resulting in continuing pulses of CO2 into the atmosphere. However, scientists still do not know how much extra carbon might result or how fast it might be released.

No silver bullet:

According to researchers at the University of California, Irvine, models may have overstated soil’s capacity to store carbon by 40%. They discovered that the average age of soil carbon is significantly older than previous estimates using data from 157 soil samples and radiocarbon testing. Large-scale soil carbon absorption from the atmosphere may take hundreds to thousands of years. According to one of the researchers, “the soil will be a big carbon sink someday, but it will not be present in the next century.”

These recent studies suggest that soil carbon storage is not a silver bullet solution to climate change. The continuing debate about its efficacy reflects how complex the system is and how much research still needs to be done.

“There is a lot of promise there since the [carbon] pool size is so huge,” Taylor stated. However, given our limited understanding of what is happening down there, we should acknowledge that although there is a great deal of potential for that pool to benefit us, there is also a great deal of potential for it to harm us. Peatlands [and permafrost] contain large amounts of soil carbon that are susceptible to volatilization into the atmosphere. It might really make climate change worse in the future.

Though scientists will keep researching how soil carbon storage can aid us in the process, reducing our use of fossil fuels and switching to renewable energy sources are ultimately the greatest ways to fight climate change. Other advantages are also offered by land management and agricultural techniques that raise soil carbon. Fertile soils keep moisture better, increase food production, support biodiversity, and are less vulnerable to desertification, erosion, floods, and nutrient loss. More microbes in the soil enable plants to grow deeper root systems that allow them to tolerate drought better, and be more resistant to pests. Enhanced carbon in soils improves soil and water quality. These are all effects that will help society feed the growing global population and be more resilient to the impacts of climate change.

A Call to Action:

Investing in soil health offers a win solution for the planet. It reduces greenhouse gas emissions, supports biodiversity, and helps stabilize weather patterns—all while enhancing agricultural productivity.

“Healthy soil is a critical instrument in the arsenal against climate change,” Taylor highlights. For a more secure and sustainable future, let us give top priority to actions that preserve and replenish this natural resource.