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Desert Revitalization as a Carbon Capture Solution: The Untapped Potential for Sequestration
The annual rate of increase in atmospheric carbon reservoirs, depicted by a blue arrow, is the difference between emissions generated from fossil fuels (9.6 Gt C), land use changes (1.2 Gt C), and the absorption of carbon into terrestrial (3.1 Gt C) and oceanic (2.9 Gt C) reservoirs. This representation only includes fluxes of carbon emanating from terrestrial sources. Source: Journal Trends in Plant Science, authored by Hirt and colleagues.
Scientists are advocating for the utilization of arid landscapes in conjunction with specialized flora and soil to establish robust carbon-capturing systems that do not interfere with land allocated for agriculture.
The mitigation of atmospheric CO2 levels requires more than merely reducing emissions. It also calls for the capture and containment of already-released excessive carbon. An opinion article recently published in the journal Trends in Plant Science on September 21 outlines that barren lands like deserts may offer a feasible solution to the challenge of carbon capture.
The authors contend that the transformation of arid regions into effective carbon-capturing ecosystems can be achieved through enhancing soil quality, increasing photosynthetic efficiency, and expanding root biomass. This can be accomplished by engineering an optimal combination of plant species, soil microbes, and specific soil types to harness a naturally occurring biogeochemical mechanism known as the oxalate-carbonate pathway, thereby creating subterranean carbon reservoirs.
According to the research group, led by senior scientist Heribert Hirt at the King Abdullah University of Science and Technology, “The focus should be on the restoration of ecosystem functions in deserts, including carbon storage. This approach presents an advantage, as it does not vie for land currently allocated to agricultural or food production operations.”
The Functionality of Oxalates in the Sequestration of Carbon
The proposed method employs plants that are well-suited to arid conditions and produce oxalates—ions composed of carbon and oxygen—which may be familiar to those suffering from ailments such as kidney stones or gout. Specific soil microbes feed on oxalates as their only source of carbon and subsequently release carbonate molecules into the soil. Though carbonate typically degrades rapidly, in alkaline and calcium-rich soils it reacts with calcium to form stable deposits of calcium carbonate.
Despite the natural cycling of carbon among the atmosphere, oceans, and terrestrial ecosystems, human activities have led to the excessive accumulation of CO2 in the atmosphere. The researchers emphasize that unless carbon is actively extracted from the atmosphere, the “…impact of elevated levels of atmospheric CO2 will be irreversible for a minimum of a millennium.”
Arid Regions Versus Forests for Carbon Sequestration
While forests are typically deemed perfect candidates for carbon capture, reforestation competes with agricultural land, thus limiting its applicability. On the other hand, arid regions, constituting roughly one-third of the Earth’s land surface, are not allocated for agriculture.
These barren ecosystems currently offer minimal support for plant life due to water scarcity as the primary limiting factor. Nevertheless, certain plant species have evolved various coping mechanisms to manage this scarcity and extreme temperatures. For example, plants categorized as “oxalogenic” generate large amounts of oxalates, which they can transform into water during drought conditions. Under specific circumstances, carbon from these oxalates is deposited underground, serving as carbon reservoirs—a mechanism the authors intend to leverage for carbon sequestration.
According to the authors, “One sixteenth of the carbon atoms fixed through photosynthesis could potentially be stored as carbonates in this form of sequestration.”
Enhancing this naturally occurring process in arid ecosystems could transition these now degraded and unproductive regions into effective carbon sinks, complete with healthier soils and plant life, propose the authors. They recommend initiating this process with “fertility islands”—small zones of revitalized habitat from which vegetation and microbes can proliferate.
The researchers anticipate that this strategy could result in substantial improvements in plant-based and soil carbon sequestration within a decade. However, they note that the efficiency and speed of implementation will be influenced by the rate of plant growth, which is typically slow in water-deficient conditions, and “will also depend on the financial and political resources available for the application of this technology in different arid countries.”
Reference: “Engineering Carbon Sequestration on Arid Lands,” authored by Heribert Hirt, Hassan Boukcim, Marc Ducousso, and Maged M. Saad, was published on 21 September 2023 in the Journal Trends in Plant Science.
DOI: 10.1016/j.tplants.2023.08.009
This research received financial support from the King Abdullah University of Science and Technology.
Frequently Asked Questions (FAQs) about Carbon Capture in Arid Lands
What is the primary focus of the research published in the journal Trends in Plant Science?
The research primarily focuses on the potential of arid lands such as deserts to serve as effective carbon-capture systems. The scientists advocate for the use of specialized plants and soil types to create robust carbon sinks that do not compete with land allocated for agriculture.
How does the proposed carbon capture method work?
The method involves engineering an optimal mix of plant species, soil microbes, and specific soil types to facilitate a naturally occurring biogeochemical process called the oxalate-carbonate pathway. This process results in the creation of below-ground carbon reservoirs, effectively capturing carbon from the atmosphere.
What advantage does carbon capture in arid lands offer over other methods?
The primary advantage is that arid lands, which make up about one-third of the Earth’s terrestrial surface, do not compete with lands used for agriculture or food production. This makes them a viable alternative to forest-based carbon capture methods, which often compete with agricultural land.
What role do oxalates play in the proposed carbon capture method?
Oxalates are ions produced by certain arid-adapted plants. These ions serve as the sole carbon source for specific soil microbes, which in turn release carbonate molecules into the soil. When present in alkaline and calcium-rich soils, these carbonates react with calcium to form stable deposits of calcium carbonate, facilitating long-term carbon sequestration.
What are “fertility islands” and why are they important?
“Fertility islands” are small zones of revitalized habitat where the initial implementation of this carbon-capture strategy would begin. These islands would serve as the starting points from which plant life and soil microbes could proliferate, eventually forming a more extensive carpet of vegetation that could serve as an effective carbon sink.
What are the anticipated outcomes of implementing this carbon capture method?
The researchers estimate that implementing this strategy could result in substantial improvements in both plant-based and soil carbon sequestration within less than a decade. However, the success and speed of the method depend on various factors, including rate of plant growth and available financial and political resources.
Who funded the research?
The research received financial support from the King Abdullah University of Science and Technology.
More about Carbon Capture in Arid Lands
- Trends in Plant Science Journal
- King Abdullah University of Science and Technology Research Funding
- Carbon Sequestration Methods: A Comparative Analysis
- Oxalate-Carbonate Pathway: An Overview
- Arid Ecosystems and Climate Change Impact
- Carbon Capture Technologies: Policy and Implementation
- Agricultural Land Use and Carbon Emissions: A Global Perspective
- Soil Microbes and Their Role in Carbon Capture
10 comments
Never thought deserts could be so useful in combating climate change. Very innovative.
Using ‘fertility islands’ as a starting point is clever. Kind of like a beta test for the whole system.
So its not just about cutting emissions, we’ve also got to think about capturing what’s already there. eye opening stuff!
this is groundbreaking stuff. Cant believe we haven’t looked into this before.
This research seems really promising. Finally, a solution that doesn’t fight with agricultural land for space. Good job!
How fast can this be put into action? Because we’re running outta time, climate change isnt waiting.
The use of arid lands for carbon capture could be a game changer. But, what about the native ecosystems, won’t they be affected?
Can’t help but wonder how this will actually play out in various arid countries with different policies and resources.
What a well-thought study. Would love to read more about the oxalate-carbonate pathway, seems like the key element here.
How realistic is it to implement though? Researchers always have grand ideas but what about the financial and political hurdles.