When people discuss genetic engineering, they usually think of the production of GMOs for human consumption, but the potential of genetic modification ranges much further. Genetic engineering has limitless applications, and one facet researchers are currently investigating is combating global warming. The greenhouse effect that is responsible for global warming is a result of the accumulation of greenhouse gases, most notably carbon dioxide. By genetically engineering plants to be more efficient at consuming and storing CO2, scientists can decrease the amount of CO2 accumulating in the atmosphere. These plants edited to sequester carbon at an advanced rate are called bioengineered/genome-edited carbon capture and sequestration or BE/GEd-CCS crops, and could play a major role in countering the emissions of the agriculture sector.

When it comes to making a plant better at sequestering carbon, there are two aspects that should be examined: absorption rate and storage. An enhanced absorption rate allows for more CO2 to be taken from the atmosphere, and a greater root capacity puts that CO2 into the soil instead of remaining in plant tissue, which would be released back into the atmosphere upon the death and decomposition of the plant. In addition to genetically modifying plants, researchers are investigating the effects of transgenic bacteria, as the composition of bacterial populations in soil can affect carbon storage capacity in the soil.

One mechanism to enhance the absorption rate of CO2 currently being researched involves preventing photorespiration. RuBisCO is an enzyme involved in photosynthesis, playing a key role in the Calvin Cycle, which is the process in which plants store the energy they get from the sun in bonds between carbons, which they derive from ambient CO2. RuBisCO is extremely inefficient, especially because it can perform photorespiration, in which it binds to oxygen instead of CO2, which happens increasingly at high temperatures. This is harmful to plant survival and does not consume any CO2, causing researchers to look for a solution. One natural method forged by evolution is seen in C4 plants, which prevents RuBisCO from binding with oxygen by physically separating them.

To compare potential mechanisms for increasing carbon storage capacity in the soil, researchers must be able to see how the soil is affected by GM traits. Measuring carbon sequestration is tricky, as there are many types of carbon that can be stored in the soil, and different methods of measurement yield different results regarding how much carbon is actually sequestered. The advancement of measurement tools is not only important for the development of GM solutions, but are also warranted for companies that sell carbon credits. Contradicting claims about the amount of carbon sequestered indicate inaccuracy and foster uncertainty about buying them. Purchasing offsets is a choice made by climate-conscious individuals and isn’t required by law, so the sale of carbon credits is not regulated consistently, but starting in 2024, the USDA will encourage farmers to pursue the voluntary carbon market, meaning that they will help farmers produce, authenticate, and sell carbon credits. More research should be done to establish and authenticate proper methods of examining carbon sequestration, because researchers must ensure that carbon is being captured at an elevated rate and that it has no negative impacts on soil for a GM plant to be introduced as a climate solution. 

In combination with modifications for increasing the rate of carbon absorption and storage, GM plants may also be given transgenes such as Bt or glyphosate resistance to increase fitness, making them easier to cultivate and maintain. The addition of such traits likely won’t jeopardize the amount of time or likelihood of GMO approval, as they have already been examined by regulators.

Although these GM crops could be extremely beneficial for the environment and the study of carbon sequestration, they must be introduced in a mindful manner. Rigorous studies and clear communication is essential for introducing GMOs, because consumers should feel confident in their safety and that no information is being kept from them. Fear is one of the strongest opponents of genetic modification, so providing all knowledge surrounding the development of BE/GEd-CCS organisms is crucial to assure concerned individuals that there are no dark secrets being buried. Additionally, the introduction of BE/GEd-CCS plants must be handled carefully; if not addressed by effective communicators, BE/GEd-CCS crops stand to perpetuate agricultural inequality seen in the US. Over time, medium-sized farms have decreased in prevalence, which has “disproportionately harmed black farmers” and has the potential to be enforced by BE/GEd-CCS crops. Larger farms are more fit to absorb transaction costs required to engage in the voluntary carbon market, so communicators involved in these GM solutions should work with others to make BE/GEd-CCS crops a viable option for smaller farms.

BE/GEd-CCS crops have received funding for research and development by private investors and might be further backed by the NBBI (National Biotechnology and Biomanufacturing Initiative), as these plants align with one of their Ten Bold Goals for Climate Change Solutions, which involves the use of biotechnology to enhance carbon sequestration.

It is incredible that technology has been developed to such an extent that plants can be engineered to be better at photosynthesis and storing the carbon they absorb. The advancements made in studying BE/GEd-CCS plants could be extremely meaningful for the environmental impact of the agricultural sector, as it was responsible for  29% of GHG emissions globally in 2023 check  (IPCC, 2023)

This article was sent to me by Joseph Gakpo, who you might remember as the journalist I interviewed last Fall. It’s really encouraging to see how genetic engineering can be used to combat climate change, and this paper brought a lot of important details regarding the consequences of applying BE/GEd-CCS crops to my attention that I might not have otherwise considered. I was hoping to learn about specific projects on this topic, and I didn’t see any elaboration on how the soil microbiome can be optimized for BE/GEd-CCS plants, but I did learn quite a bit from this review. Maybe in the future I’ll look into individual studies about BE/GEd-CCS organisms, so if that sounds interesting, stay tuned to learn with me!

https://www.frontiersin.org/articles/10.3389/fsufs.2024.1329123/full