Plants Naturally Remove Carbon Dioxide from the Air

Plants secure carbon from the air, and through the process of photosynthesis the carbon is stored in the soil, as well as in their plant structure and roots. The first 8 or 10 feet of soil currently holds more than three times the carbon that is in the air, and is capable of holding far more. Obviously we need to reduce CO2 emissions in the first place, but one of the most economical ways to remove carbon from the air is by using plants. We have always known that plants do this, it is a wonder it has taken so long to take better advantage. There are two ways to do this: Identify and increase the use of the greatest carbon fixing plants; and increase genetically manipulated carbon fixing plants (which is still controversial).

The capacity to carbon fix varies in plants. Carbon is a source of energy for plants. During photosynthesis CO2 is taken from the air, carbon is removed and stored for growth, and oxygen is released back to the air. The carbon is stored in the plant roots and also “leaks” into the soil. What a perfect opportunity to take advantage of! Identify plants with the highest capacity for carbon fixing and determine how to make greater use of those.

Research indicates that plants with well developed, deep root structures are able to sequester carbon very effectively. Plants with the largest root systems tend to also have the largest above ground structure. Trees, in fact, are a perfect example of the best carbon sequesters. But even with crops, which tend to have above and below ground structures out of balance, appropriate supply of nutrients can encourage greater and balanced growth of plant and root. Improvement to a plant's root structure additionally benefits soil structure and drought tolerance, which further benefit carbon retention in the soil. Multi-stemmed shrubs are also excellent carbon fixers. Shrubs are well branched full foliage photosynthesis machines that grow quickly, taking in carbon dioxide quickly to fuel their growth, and deposit large amounts of carbon in their extensive roots and surrounding soil. Native shrubs will also regenerate quickly after wildfire, aiding in erosion control and moisture retention when rain replenishes the soil.

In our own backyards as well as prairies, institutional land and large commercial landscapes, deep rooted perennial grasses are an excellent choice to contribute to carbon sequestering. Trees of course are the most valuable in sequestering carbon. Perennial native flowering plants are typically deep rooted, but just about any perennial is a better choice than annuals or shallow rooted grasses. The exception of course would be nitrogen fixing annual cover crops that prevent erosion and benefit the soil with nitrogen and organic material. Other cover crops used in long term soil restoration benefit the soil in a variety of ways in addition to capturing carbon. Tall sorghum with a network of fine roots and daikon radishes pushing deep into the soil are such examples.

We can also encourage greater carbon sequestering in our lawns. Typical maintenance of a lawn is not at all conducive to sequestering carbon. But if we fertilize moderately at most, water deep but infrequent, and leave grass clippings lay on the lawn, your greedy suburban lawn can certainly sequester more carbon. Those of us practicing sustainable gardening and incorporating native plants already see the benefit of “minimal” lawn maintenance.

Once carbon is sequestered deep into the soil, it is also important to help hold it there. In all sectors of soil use, farming, commercial, and residential, we need to reduce or eliminate tilling and digging; improve erosion control; organically improve the soil; and employ the use of cover crops.

Although controversial, increasing genetically manipulated carbon fixing plants could quickly advance the carbon sequester of what nature is already doing with plants. ‘Ideal Plants’, pioneered by botanist Dr. Joanne Chory, are already being developed with the use of gene editing. The plants being developed and tested are wheat, soybean, corn and cotton. The intention is for the plants to have deeper and stronger root systems that are highly effective at holding carbon. In theory, wide scale use of these plants could make an enormous difference in the amount of CO2 removed from the air, and do so very affordably. Gene Editing targets a very specific location in a DNA sequence, inserting an unrelated gene. Controversy, of course, due to objection to the general umbrella of Genetic Modification.

As I have noted else where, the entire subject of climate change is enormous. The study of plants that fix carbon is enormous on it’s own, so this is but a very brief summary of a wealth of knowledge available on the subject. What our plants can do to help mitigate climate change is amazing. A very interesting bit of information also came to light, some of the plant species with the highest carbon stores also have medicinal properties and are used in ingredients for medicines. Shouldn’t surprise us once we understand the power of carbon to fuel our plants.