One of the primary drivers of climate change is excess greenhouse gases like carbon dioxide in the atmosphere. Mitigating climate change in the coming century will require both decarbonization — electrifying the power grid or reducing fossil fuel-guzzling transportation —  and removing already existing carbon dioxide from the atmosphere, a process called carbon dioxide removal.

Researchers at the Georgia Institute of Technology and Yale University are proposing a novel pathway through which coastal ecosystem restoration can permanently capture carbon dioxide from the atmosphere. Seagrass and mangroves — known as blue carbon ecosystems — naturally capture carbon through photosynthesis, which converts carbon dioxide into living tissue.

“Mangroves and seagrasses extract carbon dioxide from the atmosphere all day long and turn it into biomass,” said Chris Reinhard, an associate professor in the School of Earth and Atmospheric Sciences (EAS). “Some of this biomass can get buried in sediments, and if it stays there, then you’ve basically just removed carbon dioxide from the atmosphere.”

Restoring these ecosystems could potentially benefit local flora and fauna and help to energize coastal economies. But Reinhard and colleagues now suggest that restoring them could also remove additional carbon through a novel pathway while combating increasing acidity in the ocean.  

In May, they presented their research in “Ocean Alkalinity Enhancement Through Restoration of Blue Carbon Ecosystems” in Nature Sustainability.

Carbon 101

There are two major types of carbon that cycle through the Earth system: organic carbon and inorganic carbon. Organic carbon is contained in living matter, such as algae, plants, animals, and even humans. This form of carbon can remove carbon dioxide from the atmosphere temporarily, but if it becomes buried in sediments at the seafloor, it can lead to permanent carbon dioxide removal. Inorganic carbon can also be found in many forms, including rocks and minerals, but is present as a significant dissolved component of ocean water. Roughly 30% of the carbon emitted by human activities since the industrial revolution is now stored as dissolved inorganic carbon in the ocean. Although carbon dioxide stored as organic carbon can be disrupted, effectively redistributing carbon dioxide back into the atmosphere, carbon dioxide removal by inorganic carbon is potentially much more durable.

“Even if you change the way a coastal ecosystem restoration project is operating, potentially remobilizing previously stored organic carbon, inorganic carbon capture is largely a one-way street,” said Mojtaba Fakhraee, lead author of the study and former postdoctoral researcher in EAS. “So even if a massive ecosystem disruption in the future undoes organic carbon storage, the inorganic carbon that has been captured will still be in the ocean permanently.”
 

Capturing Carbon, Counteracting Acidity

Coastal ecosystems naturally remove carbon from the atmosphere and provide a range of environmental and economic benefits to coastal communities, but many human interventions have caused extensive degradation or destruction of natural coastal environments. Planting more mangroves and seagrasses, maintaining them, and protecting the overall ecosystem can restore their functioning and lead to additional carbon removal from the atmosphere. Reinvigorating coastal ecosystems as a technique for mitigating carbon emissions is not a new idea, but past research has focused on carbon removal through organic carbon burial and has not explored the potential for carbon removal through the formation of inorganic carbon.

Another major result of human fossil fuel use beyond climate change is ocean acidification from carbon dioxide in the atmosphere dissolving in the water and driving down the pH of the ocean, which can have severe, negative impacts on many organisms like corals. Storing carbon dioxide as inorganic carbon in the ocean could help mitigate this, because the chemical processes that lead to carbon capture as inorganic carbon involves alkalinizing ocean waters.

“The basic idea here is that you are shifting the acid-base balance of the ocean to drive conversion of carbon dioxide in the atmosphere to inorganic carbon in the ocean,” Reinhard said. “This means that the process can help to partially offset the negative ecological consequences of ocean acidification.”

Modeling Carbon Capture

To explore how effective restoring coastal ecosystems could be for inorganic carbon capture, the researchers built a numerical model to represent the chemistry and physics of sedimentary systems — the complex mixture of solid particles, living organisms, and seawater that accumulates at the seafloor. A key advance of the model is that it specifically tracks the potential benefits of restored mangrove or seagrass ecosystems and their impacts on organic and inorganic carbon cycling. It also calculates the effects of other greenhouse gases, such as methane, that can sometimes be created in the process of restoring mangrove and seagrass ecosystems.

“This model comes up with representations for the rates of carbon transformation in the sediment based on how much mangrove is growing above the sediment,” said Noah Planavsky, senior author on the study and professor of Earth and planetary sciences at Yale. “We found that across an extremely large range of scenarios, restoration of blue carbon ecosystems leads to durable carbon dioxide removal as dissolved inorganic carbon.”

The team hopes this research could provide an impetus to protect current coastal ecosystems and economically incentivize restoration of degraded ecosystems, potentially as a new form of carbon offset.

“Companies that are trying to offset their own emissions could potentially purchase carbon removal through funding restoration of coastal ecosystems,” Reinhard said. “This could help rebuild these ecosystems and all of the environmental benefits they provide, while leading to durable carbon dioxide removal from the atmosphere.”

CITATION: Fakhraee, M., Planavsky, N.J. & Reinhard, C.T. Ocean alkalinity enhancement through restoration of blue carbon ecosystems. Nat Sustain (2023). https://doi.org/10.1038/s41893-023-01128-2

Georgia Tech’s Sustainability Next Institute Strategic Plan initiative launched an annual seed grant program totaling $250,000 to support interdisciplinary or transdisciplinary climate and sustainability research. The overarching goals of the initiative are to nurture promising areas for future large-scale collaborative sustainability research, research translation, and/or high-impact outreach; to provide mid-career faculty with leadership and community building opportunities; and to broaden and strengthen the Georgia Tech sustainability community as a whole.

The Brook Byers Institute for Sustainable Systems (BBISS), which is administering the initiative modeled after the Office of the Executive Vice President for Research’s (EVPR) “Moving Teams Forward” and “Forming Teams” programs, put out a call for proposals this Spring. Proposal reviewers consisting of academic and research faculty at Georgia Tech were invited and assigned to review a minimum of three proposals each. The complete panel of reviewers discussed the relative merits of each proposal and made recommendations to the Interim Executive Director and Deputy Director of the BBISS. Ultimately three were chosen in the “Moving Teams Forward” category, and three in the “Forming Teams” category.

“I’m delighted that the transdisciplinary focus of the call achieved its purpose – accelerating team-based climate work that strengthens our community-engaged research infrastructure and HBCU partnerships with an emphasis on community engagement,” said Beril Toktay, interim executive director of the BBISS.

The proposals selected for funding are:

Moving Teams Forward

• Collaborative Approaches to Research Engagement (CARE): Building and Validating a Community-Centered Realist Approach to Human Subjects Recruitment; Lewis Wheaton (BIOL), Karen Minyard (Georgia State), Jennifer Hirsch (Center for Serve-Learn-Sustain), Melanie J Clark (Office of Research Integrity); Chris Parker (Georgia State), and Lea T. Marzo.
• Nurturing Climate-Aware Knowledge Networks for Environmental Justice-Oriented Design; Neha Kumar (INTA), Vishal Sharma (IAC), Anjali Karol Mohan (Integrated Design, India), Bonnie Nardi (UC Irvine), Aaditeshwar Seth (IIT Delhi), and Gayathri Muraleedharan (Integrated Design, India).
• Urban Heat Atlanta - Moving Forward; Brian Stone (SCRP), Christopher Le Dantec (IAC), Russell Clark (College of Computing), Kim Cobb (Brown University), Jairo Garcia (College of Design), and Na’Taki Jelks (Spelman University).

Forming Teams

• Building a Virtual Sustainability Lab for Climate Adaptation in Megacities – Urban Flood Modeling as a Prototype; Yi Deng (EAS), Xiaoming Huo (ISYE), and Jian Luo (CEE).
• Low-carbon Building Materials for Climate Adaptation and Mitigation; Ebenezer Fanijo (BC), Ece Erdogmus (BC), Kimberly Kurtis (CEE), and Giovanni Loreto (Kennesaw State).
• Heritage BIM and Sustainable Tourism; Danielle Willkens (ARCH), Junshan Liu (Auburn University), Maria Jose Viñals (Universitat Politècnica de València, Spain), Russell T. Gentry (ARCH), and Ece Erdogmus (BC).

The second round for this call is now open for the Fall of 2023, with submissions due on September 15. Details and application instructions can be found on InfoReady.

Overall greenhouse gas emissions in Georgia fell by 5% between 2017 and 2021, mostly due to the increased use of natural gas and solar for electricity generation, according to the research team behind the Drawdown Georgia climate initiative. Emissions from agriculture and the average individual carbon footprint also shrank.

The decline in emissions comes against a 10% expansion in the state’s economy, showing the potential for reducing emissions while pursuing economic growth, according to the team.

However, the team’s data also show a stark increase in transportation-related emissions, which now exceed pre-pandemic levels and has become the state’s largest source of climate pollution, according to Marilyn Brown, Regents’ Professor and Brook Byers Professor of Sustainable Systems in the School of Public Policy and the principal investigator on the Drawdown Georgia research team.

“While not all of the numbers are trending in the right direction, these data clearly show significant improvements in many sectors of our economy and also highlight where we have the greatest opportunities, namely transportation,” Brown said.

Track Greenhouse Gas Emissions in Your County

The report shows that while emissions from the electricity sector declined more than 15% between 2017 and 2021, transportation sources including cars and trucks put out 4% more climate-warming emissions in 2021 than five years earlier. Emissions from diesel vehicles spiked 16.1%, likely due to increased demand for delivery services driven by online shopping.

Emissions from Georgia’s agricultural and food sector fell by 7.1% during the study period while the average individual carbon footprint of Georgians declined from 22,092 pounds to 20,253 pounds.

“Based on the collaborations we’re a part of, we’re confident this is only the beginning of Georgia’s carbon reduction trend,” John Lanier, executive director of the Ray C. Anderson Foundation, said in a news release on the findings.

The foundation is a primary funder of Drawdown Georgia.

Brown leads the research team, which spans several Georgia colleges and universities. She is an internationally known climate policy researcher who has dedicated most of her career to helping solve the climate crisis.

The analysis is based on data from the first-of-its-kind Drawdown Georgia Emissions Tracker, which aggregates information from federal Energy Department, Transportation Department, and Environmental Protection Agency reports. The tracker was produced by a team of scientists led by William Drummond in the School of City and Regional Planning.

For a more detailed analysis of the findings, visit the Drawdown Georgia blog.

The Renewable Bioproducts Institute (RBI) at the Georgia Institute of Technology has launched a new science and technology research center called ReWOOD. The ReWOOD launch included a 2-day workshop involving faculty research partners from universities across the Southeast, as well as former Georgia Agriculture Commissioner Gary Black.

ReWOOD, abbreviated from “Renewables-based Economy from WOOD” will focus on a burgeoning field of science called Xylochemistry. Xylochemistry makes use of sustainable plant-based raw materials to develop industrial products ranging from jet fuel to industrial solvents to generic pharmaceutical additives and more. Right now, most of the world production of such materials comes from non-renewable fossil resources or petroleum products. Moving to a renewable source will not only aid in reducing the dependence on fossil fuels but will also help with reducing the overall carbon footprint. ReWOOD is sponsored by RBI through its endowment-funded fellowships and is developing a corporate affiliate program.

“The formation of this internal research center will drive regional momentum for producing carbon neutral chemicals and fuels from wood wastes deriving from the abundant and fast-growing wood in the Southeast,” said Carson Meredith, executive director of RBI. “In fact, the Southeast has a larger percentage of sustainably grown working forests than any other area in the U.S., and Georgia is the number one exporter of forest products in the nation.”

Research on chemical renewables via Xylochemistry has been ongoing at Georgia Tech under a consortium called GT-STANCE (Science & Technology for a Neutral Chemical Economy). GT-STANCE’s researchers have developed seed technologies that aid in the production of wood-based chemical intermediates with potential uses in consumer commodities like pharmaceuticals and plastics. In addition, RBI has made a significant investment of nearly $3 million in building research teams in the related area of lignin conversion in the last five years. The formation of a research center that will coalesce regional thought leadership is the logical next step, as a renewables-based economy has become a national priority with the bioeconomy, climate, and clean energy goals set by the Inflation Reduction Act and the Bipartisan Infrastructure Law.  

Raw materials for Xylochemistry could also be sourced from any kind of non-treated wood. For example, wood from demolished construction sites like old homes and wooden buildings provide an excellent opportunity for a circular economy, since this wooden construction waste ends up in landfills now.

Currently ReWOOD has 11 university affiliates that are joining Georgia Tech. In January 2023, faculty from Georgia Tech, the University of Alabama at Tuscaloosa, and Alabama A&M University convened to discuss the plans for a research center on a renewables-based economy from wood to develop renewable biofuels, industrial solvents, pharmaceutical additives, and many other products that culminated in the formation of ReWOOD. Since then, the center has gained the interest of multiple other researchers from the University of Florida, Kennesaw State University, and Clark Atlanta University. In addition, the Mississippi State and Forestry Office and Sandia National Laboratory have become key collaborators within ReWOOD. This collection of expertise includes chemists, engineers, economists, and forest experts, covering a broad range of activities that will include technology, economic, and workforce development, as well as lifecycle and socio-economic analysis. This partnership list will continue to evolve and grow as ReWOOD focuses on specific target research areas and proposals for funding to develop technology and processes in the business sector.

About the Renewable Bioproducts Institute at Georgia Tech
Georgia Tech’s Renewable Bioproducts Institute is one of ten campus interdisciplinary research institutes. RBI champions innovation in converting biomass into value-added products, developing advanced chemical and bio-based refining technologies, and advancing excellence in manufacturing processes. Our three strategic thrusts are circular materials, bio industrial manufacturing, and paper, packaging, and tissue.

RBI serves as a campus conduit for industry-university partnerships and provides a portal to Georgia Tech core laboratories, faculty and students whose work and expertise is focused on biomass and bioproducts.

The 2022-23 Micro-Grants Community-Based Research awardees presented their findings at the second annual symposium, held on April 18, 2023, in the auditorium of the Kendeda Building for Innovative Sustainable Design, which is the region’s first Living Building. Ten teams presented to faculty, staff, students, and student family members. The topics were wide ranging, and dealt with both practical and theoretical issues. The work surpassed all expectations for quality and quantity.

Devised by the Kendeda Building Advisory Board and sponsored by the Brook Byers Institute for Sustainable Systems and the Kendeda Building, the Micro-Grants Research Program solicits proposals for very small scale ($50 to $500), short term, sustainability related, research studies to be conducted by members of the Georgia Tech community. Community investigators are encouraged to explore ways in which the Georgia Tech campus can continue to innovate, demonstrate, prove, and promote the adoption of best and next practices in regenerative design and operations. Researchers were also encouraged to use the United Nations Sustainable Development Goals as a framework for research design. All members of the Georgia Tech community were encouraged to apply. The program especially sought proposals from students and staff that had little or no prior research experience.

The program has four objectives:

1. to expand scientific thinking and the understanding of the research process amongst those not (yet) directly involved in scientific research;
2. to bolster the use of the campus as a living laboratory;
3. to give voice to people and communities outside of research that have culturally novel perspectives on problems and their possible solutions, and to create new pathways for partnering with them; and
4. to seed novel ideas and nurture nascent investigators.

The 2022-23 awardees and the titles of their projects are:

• Alex Lomis, Devi Patel, and Dr. Jung-Ho Lewe, "Design and Development of a Low-Cost and Highly-Scaleable Occupancy Counter to Optimize the Utilization of HVAC Resources"
• Kaitlyn Tran, Shivani Potdar, and Amanda Janusz, "Bird Safe Campus"
• Ricardo Martinez, "Chiropterans at Georgia Tech"
• Elizabeth Umanah, "Reimagining Eco-Friendly Parking Lot Design Through Simulations"
• Lujain Diab, Ally Kimpling, Jenna Sitta, Marcus Morris, Skylar Ryan, Dr. Jennifer Leavey, and Steve Place, "A Greener Grey: “Ironing” Out Issues in Greywater Systems"
• Jun Wang and Yilun Zha, "Kendeda’s Educational Role in Waste Management and Recycling"
• Siddharth Sivakumarun, "Investigating Capacity for Regenerative Energy through Foot Traffic"
• Alexandra Rodriguez Dalmau and John Fortner, "Recognition of Insect Species in the Georgia Tech campus with Machine Learning"
• Gray Simmons, Kevin Leach, and Dr. Jung-Ho Lewe, "IOT Climate Sensor Development for HVAC Efficiency Analysis"
• Kaylin Cross, Pranav Jothi, Maanas Kumar, Brian Wu, Savannah Howard, and Sheng Dai, "Prototyping Bio-inspired Geothermal Energy Recovery for Space Heating and Cooling"

More details and links to all the presentations are available at this web page.