In a recent opinion paper published in the journal Trends in Plant Science on September 21, a group of plant scientists has put forth an intriguing idea for combating rising CO2 levels in the atmosphere. They propose that arid lands, such as deserts, could hold the key to the carbon-capture challenge.
The scientists argue that by engineering the right combinations of plants, soil microbes, and soil types, we can transform these arid ecosystems into efficient carbon-capture systems. This approach aims to harness a natural biogeochemical process known as the oxalate-carbonate pathway to create subterranean carbon storage.
The concept involves “re-greening” deserts by enhancing soil health, boosting photosynthetic efficiency, and increasing root biomass. This not only mitigates carbon emissions but also avoids competition with agricultural land.
The core idea revolves around arid-adapted plants that produce oxalates. Some soil microbes consume oxalates as their primary carbon source and release carbonate molecules into the soil. When these plant-microbe systems are cultivated in alkaline, calcium-rich soils, stable deposits of calcium carbonate form.
Human activities have led to excess CO2 in the atmosphere, and even with emissions reductions, these effects are long-lasting. The researchers emphasize the need for atmospheric CO2 sequestration to address climate change effectively.
While trees are often considered for carbon capture, reforestation competes with agricultural land. In contrast, arid lands, covering about one-third of terrestrial surfaces, remain untapped for agriculture.
Arid-adapted plants have evolved unique mechanisms for surviving in water-scarce environments, such as deep-reaching roots and specialized forms of photosynthesis. Some “oxalogenic” plants produce substantial oxalates, which can be converted into water during droughts. Importantly, a portion of the carbon from these oxalates is deposited underground as carbon reserves—an aspect the authors aim to exploit.
The authors estimate that this approach could significantly increase plant and soil carbon sequestration within a decade. However, success depends on factors like plant growth rates (often slow in water-scarce conditions) and the financial and political resources available for implementation in arid regions.
In summary, this innovative strategy seeks to harness the untapped potential of arid lands to combat climate change, offering a promising solution to the carbon-capture challenge.
Source: Cell Press