Switch to compact fluorescent light bulbs and plant a tree – these are some popular suggestions for practical steps people can take to help mitigate climate change. But the truth is, we are standing on one of the most overlooked, most effective and least expensive strategies available: store carbon in the soil.
The earth's soil contains the second-largest quantity of carbon (the largest amount is dissolved in oceans). Unfortunately, many of our modern day practices – including the removal of fossil fuels for use as an energy source and the tilling of land for agriculture crops – has resulted in an increase in carbon present in the atmosphere. This has led to global climate change.
How do we encourage the movement of carbon from the atmosphere to the soil? We need the help of plants to accomplish this. However, it needs to be the right plants in the right place.
Planting trees might sound like a flawless idea since trees absorb large quantities of carbon. But trees are not always the best solution. In areas that were originally covered in wetlands and grasslands, native, deep-rooted grassland plants are much more efficient in the sequestering of carbon. Native grassland plants also use water resources more efficiently, contribute greater amounts of organic matter to the soil, and are better adapted to handling drought conditions. The ecological lesson is that we should plant trees only where the soil will benefit from it.
Another way we can change the amount of carbon stored in soil is to promote techniques that reduce the release of carbon from the soil into the atmosphere. One example is "no-till" farming, in which farm-seeding equipment inserts crop seeds into slits cut into the undisturbed soil. Farmers have reported that no-till agricultural practices delivered savings in just 2 to 3 years and increased crop yields by 10 percent. It also reduced fossil-fuel use for farm machinery by 90 percent.
No-till agriculture also leaves leftover plant matter on the land, which means the technique can add up to 1.3 inches of soil materials and organic matter per acre over the next 50 years. The many feet of new soil would be a sponge to hold back runoff and nutrients from entering rivers and lakes and hurting potable water supplies. It would also help reduce costly, damaging floods.
Ranchers can also contribute by using grazing practices that emulate the way bison used to graze. They moved quickly over the landscape – consuming then moving on-- and not returning to the same location for an extended period, often years. Ranchers now can graze their cattle on deep rooted native grasses and wildflowers, and keep the cattle and sheep “moving”, with short stops in each paddock, allowing a longer plant recovery period compared to conventional grazing where cattle may access the same paddock and wear down the energy and recovery potential of each eaten plant every day.
Scientific analyses show that recapturing atmospheric carbon into soil and plant communities is the easiest and least expensive method for mitigating climate change and that it provides many other economic, cultural, and ecological benefits. Restoring soils in currently farmed land can rein in 10 to 15 percent of the annual carbon emissions Americans create. Replanting native grasslands and restoring drained wetlands can reduce up to another 20 percent. We need to follow nature's lead and put carbon where the earth has securely stored it for millions of years – in the soils. Among many other benefits, this will cleanse the atmosphere, taking a big bite out of the existing greenhouse-gas loads.
Unfortunately, few Americans are aware of the power of the land below their feet to help balance our environment. Teaching children about the importance of soil is another way educators and parents can help fight climate change. Children need to be encouraged to play and explore soil so they will grow to appreciate its contribution to our global community. It is never too early to begin learning about the importance of soil. With the help of teachers, they will understand that what they stand to learn about soils is essentially important to their future and that of all other species on earth.
Steven I. Apfelbaum is a senior ecologist with Applied Ecological Services, Inc., in Brodhead, Wis. He and others at AES are part of a global team of scientists researching how to re-grow healthy soils for the benefit of people, climate, water cycles, biodiversity, and food systems on earth. Steve co-teaches a course on the future of coastal ecosystems at Harvard Graduate School of Design, Cambridge, and lectures regularly at various other universities. For more of Steve's writing on soil as a carbon sink, enjoy The role of ruminants in reducing agriculture’s carbon footprint in North America, for the Journal of Soil and Water Conservation.
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