Human

Soil sequestration

 By Michelle Leslie

Three-quarters of the world’s carbon is stored in soil, making it a key weapon in the fight against climate change. In fact, there’s increasing evidence that the long term storage or sequestration of carbon in soils will play a critical role in stabilizing global temperatures. However, industrial agricultural practices have been doubly damaging. Stripping carbon from our soil while at the same time flooding our atmosphere with it. But there is a way to bring back our soil’s health, as well as that of the planet. It’s called regenerative agriculture, made up of farming practices that rely less on tilling and disturbing the very dirt we need to grow food…

(Cover photo by Charles Knowles, Flickr)

Dirt.

It’s a major building block of life on Earth and it’s found under our feet. Now, with the world gearing up its fight against climate change, dirt is taking on even more importance, because three-quarters of the world’s carbon is stored in soil.

According to the International Panel on Climate Change (IPCC), CO2 emissions rose almost 20 percent between 1995-2005. The increase of CO2 in the atmosphere leads to a condition known as radiative forcing (RF), and its effects are becoming more pronounced, as global temperatures rise and the climate changes rapidly.

Unfortunately, current industrial agricultural practices are accelerating this damage, stripping carbon from our soil and releasing it into the atmosphere .

According to World Resources Institute, in 2011, farms accounted for 13% of total global emissions. That startling statistic means more attention is being paid to the long-term storage or sequestration of carbon in soils, as this can play a critical role in stabilizing global temperatures.

Photosynthesis is the process by which plants take in sunlight, water and carbon from the atmosphere and turn it into energy in the form of oxygen. Increasing the amount of greenery is like sticking a vacuum cleaner into the atmosphere and sucking out the carbon. Plants are nature’s vacuum cleaner. The more of them that grow, the more carbon is sucked out of the atmosphere and drawn back into the dirt. And even when the plant dies and decomposes, most of that carbon stays out of the atmosphere. Instead, it is added to the soil.

Regenerative Agriculture Techniques – Capturing Carbon on the Farm

To retain this benefit, the key is to find ways to keep that carbon in the soil. One solution is regenerative agriculture — farming practices that rely less on tilling and disturbing the dirt we need to grow food. It’s a more natural approach, growing diverse crops, using compost and trees to help keep the soil healthy and productive.

Agroforestry is one such approach to help improve agricultural lands and sequester carbon to soil, and has been long practiced in China. Eleven of Asia’s rivers are responsible for supplying over one-fifth of the world’s population with water. Agroforestry, or integrating trees with farmland, can help preserve these critical water supplies as healthier lands require less water — they are better equipped to store and hold moisture, which in turn improves environmental conditions and can even reduce poverty. A byproduct of improving the amount of carbon in soil means higher yields and more nutrient rich foods.

In China, home of the World Agroforestry Center, they have shown a strong understanding of how ecosystems will interact with different species of trees. This methodology helps to create environments that are more resilient to climate change while at the same time protecting natural resources.

Protecting our soils means changing how we use them.

A recent report by the United Nations Environment Program found that 25% of global land use has declined in productivity thanks to carbon being sucked out of soil. The health of soil can be found in its humus, which is a measure of the decomposition of organic materials contained within the dirt. A high humus content indicates a higher amount of organic matter which translates to more oxygen. Soils which contain more oxygen are more fertile. These carbon rich, healthier soils often reflect their vitality through their color; the more vibrant or rich the color, the more fertile the soil.

Traditional agricultural methods strip vitality from soil by removing this much needed carbon at astronomical rates. As outlined by work at the Rodale Institute, moving away from modern industrial agricultural practices to ones that rely more on cover crops, composting and crop rotation can increase food production while also being environmental friendly.

As stated in a recent paper, “data from farming systems and pasture trials around the globe show that we could sequester more than 100% of our current annual CO2 emissions with a switch to widely available and inexpensive organic management practices, which we term regenerative organic agriculture.” This low-till approach draws CO2 out of the atmosphere and back to the earth.

As outlined by the Ecological Society of America, enhancing the amount of carbon stored in soils can have huge environmental benefits, bringing back nutrients to our soil, removing greenhouse gases from our atmosphere and making our agricultural lands healthier.

 

SEE MORE: Using CO2 sequestration to boost geothermal yields by Robin Wylie

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The University of Ohio’s Carbon Management and Sequestration Center is looking at sustainable land practices as a means of improving the quality of our atmosphere, while at the same time reducing poverty. It’s a critical venture. The World Food Programme (WFP) has found that one in nine people on this planet is hungry.

As the world population swells so will the demand for food. The United Nations Environment Programme (UNEP) predicts demand will grow by 50% within the next two decades. A greater population means a greater strain on resources, including land, which makes improving the quality of farmland through carbon sequestration that more critical.

Government policies and financial incentives can ensure the maintenance and quality of the world’s soils. France is already forging ahead in soil restoration with its 4 per 1000 program. The aim is to add 4% more carbon to soil, preventing this greenhouse gas from making its way into the atmosphere. The program was launched during COP21 and at the time over 100 organizations signed on to France’s plan.

It’s a critical juncture. In a report by the IPCC, agriculture was the second leading contributor to global greenhouse gas emissions. As the world moves ahead in cutting GHG emissions, soil carbon sequestration can be a key part of the fight, addressing both food and climate security for generations to come.

about the author
Michelle Leslie
Alberta, Toronto and now Ottawa. Meteorologist, Journalist & Munk School Of Global Affairs Fellow.