People and Community Research

Harnessing Earth’s natural cycles to reverse climate change

Editor’s note: The following opinion piece was submitted as part of the inaugural “Op-ed Challenge” hosted by the University of Miami Graduate School. Open to all graduate students, entries were judged by media professionals.

On average, fossil fuel emissions do not alter the planet’s temperature for a full decade after being emitted.Atmospheric carbon dioxide (CO2) and the resulting repercussions will continue to increase, even if we stopemissions entirely today. Climate scientist Tom Green offers a metaphor, “When you overfill a bathtub, you don’t expect turning the tap down to empty the tub. Similarly, cutting emissions will not be sufficient: we need to removecarbon dioxide from the atmosphere.” It is this removal of CO2 that scientists, like Green, are prioritizing as they strive to save our planet from irreversible damage. 

Carbon dioxide does not inherently pose a threat to our environment due to the planet’s ability to recycle and utilize the compound. The release of greenhouse gasses, including CO2, occurs naturally through decomposition, volcanic venting, and forest fires. However, the industrial burning of fossil fuels has quickly accumulated CO2 in our atmosphere in harmful amounts. Without a strong enough balancing process to act as a counter force, this reaps havoc on our planet—acidifying the oceans and increasing global temperatures. 

Tom Green is the CEO of Vesta, which is a climate change research firm. Green believes that Ocean Alkalinity Enhancement (OAE) is our best bet at atmospheric CO2 removal. OAE amplifies a naturally occurringphenomenon called the geological carbon cycle. According to this process, rain dissolves layers of exposed rock that eventually wash into the ocean. The rock then undergoes a reaction with the marine environment that allows for atmospheric CO2 to be captured and stored in the ocean. This carbon dioxide can be stored indefinitely due tothe dissolved minerals’ ability to increase the pH, or reduce the acidity, of the surrounding seawater. Currently, theocean has absorbed more than 30 percent of fossil fuel emissions. Ocean Alkalinity Enhancement offers the potential to increase oceanic CO2 absorptions to 50 percent or higher in five years. 

Olivine is one of the most abundant minerals on the planet and is also one of the proposed mediums for OAE. Olivine would be ground into sand which would then be dispersed to shorelines globally. These small particles of olivine, in combination with natural wave action, accelerate the weathering process that is required for the geological carbon cycle. The enhanced weathering leads to an increase in ocean CO2 uptake and a greater reduction in ocean acidity. Researchers project that the distribution of olivine sand to only 2 percent of globalshorelines could result in the removal of international CO2 emissions annually. Not only is this a scalable climatesolution, but it is also cost effective. Olivine mining and dispersal is estimated to cost around $35 to $112 per ton of olivine which captures one ton of CO2. This climate solution has the ability to remove billions of tons of CO2 yearly, which would also include the emissions spent mining olivine. 

Critics of OAE quickly discard the climate solution due to the unpredictable ecological impacts it may pose. The ocean is a highly variable place and widespread effects are difficult to study. Olivine is rarely present in a pure form, as it is frequently combined with heavy metals, like iron and nickel. Contamination would be unavoidable inthe olivine sand. Trace metals in low amounts can serve as nutrients in marine environments; however, in highconcentrations can be toxic. This sensitive relationship needs to be monitored and there is a continuous supply of research attempting to understand it further. 

My research focuses on the environmental impacts of olivine sand as an OAE medium. Specifically, I am studying coral physiology and overall health when in contact with OAE seawater contaminated with trace metals. Corals are one of the most threatened marine animals in the world. They are essential for minimizing wave action andhousing more than 30 percent of the ocean’s biodiversity. OAE

could not be deployed globally without the assurance that it will not negatively impact coral reefs and other vital marine ecosystems. The higher pH associated with higher alkalinity is beneficial in the growth of the coral skeletonand mitigates one of corals major threats—ocean acidification. An acidic environment eats away at the coral skeleton and ultimately can result in death. 

There are various risks associated with all novel ideas; however, with OAE the question is if the rewards outweigh the potential risks. The concept is natural, scalable, and cost effective, but there is uncertainty surrounding global deployment due to the ever-changing oceanic environment. Our planet is exceptional at regulating itself andmaintaining homeostasis; yet, with an influx of anthropogenic stressors this balance has been thrown off. Currentlywe are striving to return to that balanced state. The question is if we can learn from the pre-existing earthly systems and harness their power before it is too late. 

Adeline Nagle is a graduate student in the Rosenstiel School of Marine, Atmospheric, and Earth Science at the University of Miami. Read more about the inaugural “Op-ed Challenge.”