Reducing global carbon dioxide emissions is critical to avoiding climate disasters, but current carbon removal methods are proving to be inadequate and costly. researchers propose a scalable solution to remove carbon from the atmosphere and safely store it for thousands of years using simple and inexpensive technology.
As reported today in the Proceedings of the National Academy of Sciences, researchers propose growing biomass crops to capture carbon from the atmosphere and burying the harvested vegetation in artificially dried biolandfills. This unique approach, which the researchers call agricultural sequestration, keeps buried biomass dry with the help of salt, inhibiting microbial activity and halting decomposition, and stabilizing all biomass carbon. Allows isolation.
The results are carbon negative, and the approach could be a game changer, says lead author Eli Yablonovitch, professor in the Department of Electrical Engineering and Computer Science at UC Berkeley.
“We claim that with the right engineering, we can solve the climate change crisis 100%,” Yablonovitch said. “If implemented on a global scale, this carbon-negative sequestration method could potentially remove not only current annual carbon emissions, but also atmospheric emissions from previous years.”
Unlike previous efforts towards carbon neutrality, agro-sequestration seeks to be net carbon negative rather than net carbon neutral. According to the paper, it is possible to sequester about 2 tons of carbon dioxide for every ton of dry biomass.
Agricultural sequestration: a method for stably sequestering carbon in buried biomass
The idea of burying biomass to sequester carbon is gaining popularity, with start-up organizations burying everything from plants to wood. However, ensuring the stability of buried biomass is difficult. Although there is no oxygen in these storage environments, anaerobic microbes can still survive and break down biomass into carbon dioxide and methane, making these sequestration approaches carbon-neutral at best.
But there is one thing that all life forms need. Moisture. This is measured by “water activity”, a quantity similar to relative humidity. When the water activity inside drops below 60%, all life stops. This is the concept behind a new agricultural isolation solution from researchers at the University of California, Berkeley.
“For many of these recently popularized natural and agricultural-based technologies, there are significant long-term isolation issues,” said study co-author Harry Harry, a researcher in the Department of Electrical Engineering and Computer Science. Dickman said. “Our proposed agricultural sequestration approach can stably sequester carbon in salted biomass that has been dried for thousands of years at a lower cost and higher carbon efficiency than these other air capture technologies. .”
Hugh Helferty, co-founder and president of Producer Accountability for Carbon Emissions (PACE), a non-profit organization committed to achieving net-zero global emissions by 2050, is excited about the solution. I’m here.
“Agricultural sequestration has the potential to transform temporary nature-based solutions into permanent CO.2 said Helferty, who was not involved in the study. “By developing their approach, Deckmann and Jablonovic have created an invaluable new option for tackling climate change.”
Achieving the right level of dryness to prevent decomposition
To survive, living cells must be able to transport solubilized nutrients and solubilized waste products across the cell wall. According to Deckman, lowering the water activity below 60% he has been shown to shut down these metabolic processes.
To achieve the required level of drying, Jablonovic and Deckman took inspiration from salt, a long-term food preservation technique that dates back to Babylonian times.
“Drying, sometimes with the help of salt, effectively reduces the internal relative humidity of the sequestered biomass,” Jablonovic said. “And it has been proven to prevent decay for thousands of years.”
Researchers point to a date palm named Methuselah as evidence that it can be preserved well into the next thousand years if the biomass is kept dry enough.
In the 1960s, Israeli archaeologist Yigal Yadin discovered a date palm seed among ancient ruins atop Masada, a mesa overlooking the Dead Sea, one of the driest places in the world. The seeds were kept in a drawer for over 40 years until 2005 when Sarah Salon, a doctor who studies natural medicines, requested them. plant them. They sprouted and Methuselah, his one of those dates, continues to thrive today.
“This is evidence that if you keep the biomass dry, it will last for hundreds to thousands of years,” Yablonovitch said. “So it’s a natural experiment to prove that biomass can be preserved for 2,000 years.”
A cost-effective and scalable approach
Yablonovitch and Deckman’s agricultural isolation approach not only provides long-term stability, but is also highly cost-effective. The combined costs of agriculture and biolandfills add up to US$60 per tonne of carbon dioxide captured and sequestered. (By comparison, some direct air capture and carbon dioxide gas sequestration strategies cost US$600 per tonne.)
“$60 per tonne of carbon dioxide captured and sequestered equates to an additional cost of $0.53 per gallon of gasoline,” Yablonovitch said. “At this price, offsetting global carbon emissions, the global economy would fall back by 2.4%.”
Researchers have compiled a list of over 50 highly productive plants that can grow in a variety of climates around the world and with dry biomass yields ranging from 4 to over 45 dry tons per hectare. All are selected for their carbon capture capabilities.
The solution also allows for non-encroaching and non-competing expansion of agricultural land used to grow food. Many of these biomass crops can be grown in remote meadows, woodlands and even fallow land.
“It takes a lot of farmland to remove all the carbon produced, but it’s the amount of farmland that’s actually available,” Yablonovitch said. “This will be a huge boon for farmers as there is currently underutilized farmland.”
Farmers who harvest these biomass crops dry the plants and bury them in dry, artificial biolandfills located within agricultural areas, tens of meters below ground and safe from human activity and natural disasters.
The researchers based the design of these dry grave structures on current municipal landfill best practices, but added extensions to ensure dryness. For example, he has two nested layers of 2 mm thick polyethylene encasing the biomass. This is the method already used in modern landfills.
Landfills account for only 0.0001% of agricultural land. In other words, 10,000 hectares of biomass production could be buried in 1 hectare of biolandfill. Additionally, the landfill top surface can later be returned to agricultural production.
Fast track to recruitment
Deckman said the timeline for adoption of this carbon capture and sequestration method could be short.
“Agricultural isolation is technically ready and construction of the artificial biolandfill could begin after one growing season,” he said.
Yablonovitch and Deckman’s analysis shows that farmers can transition to biomass farming fairly quickly. They estimate that it will take about a year to convert existing farmland to biomass farming, but it will take longer for savage land that lacks the necessary infrastructure to support agriculture. Biomass crops are ready for harvest and isolation during the growing season.
Using this approach, the researchers found that to sequester about half of the world’s greenhouse gas emissions (about 20 gigatonnes of carbon dioxide per year), one-fifth of the world’s arable land or 15 minutes of the world’s We calculated that we would need agricultural production from an area equivalent to 1 of . All cultivated, pasture and forest land areas. They report that this amount of land is the same or less than the total area many of the Intergovernmental Panel on Climate Change’s greenhouse gas reduction models consider for biomass production.
“Our approach to agricultural segregation offers many advantages in terms of cost, scalability and long-term stability,” said Yablonovitch. “Furthermore, existing technologies of known cost can be used to remove carbon dioxide from the atmosphere, providing a practical path to solving the problem of climate change. We must continue our work towards the development and installation of solar and wind technologies, which will revolutionize energy storage.”
Original: To sequester biomass and carbon more effectively, just add salt
Than: University of California, Berkeley
