In a bold experiment that challenges conventional wisdom, scientists are exploring an unconventional approach to combat global heating and ocean acidification. The idea, known as Ocean Alkalinity Enhancement (OAE), involves pumping chemicals into the ocean to boost its natural alkalinity, a process akin to natural weathering but on a human timescale.
The recent trial in the Gulf of Maine, where a red-dyed chemical was released, raises intriguing questions and concerns. While the results showed promise, with increased carbon absorption and a return to pre-industrial ocean alkalinity levels, the potential environmental impacts are a cause for debate.
The Science Behind OAE
OAE leverages the ocean's vast capacity to store carbon, which is currently estimated at a staggering 38,000 billion tonnes as dissolved bicarbonate. By adding an alkaline chemical, scientists aim to enhance this natural process and potentially mitigate the effects of climate change.
The experiment, conducted by a team led by oceanographer Adam Subhas, found that over five days, the chemical plume absorbed up to 10 tonnes of carbon, with no significant harm observed to plankton, fish, or lobster larvae.
Environmental Concerns and Stewardship
However, the use of chemicals to address an environmental crisis is not without controversy. Benjamin Day, a senior campaigner at Friends of the Earth US, expresses concern about the potential for "catastrophic unforeseen consequences" if OAE is implemented on a large scale.
Phil Renforth, an expert in carbon dioxide removal at Heriot-Watt University, offers a different perspective. He argues that we are already experimenting with the climate through uncontrolled means and suggests we should view OAE through the lens of stewardship.
"We're adding CO2 to the atmosphere every year, and a large proportion is going into the oceans. The question is, can we be proactive about how we manage it?" Renforth asks.
Historical Precedents and Commercial Interests
The concept of OAE is not entirely new. Liming, a practice used by Greek farmers 2,000 years ago to neutralize acidic fields, has a modern counterpart in the treatment of Scandinavian rivers affected by acid rain.
Today, several OAE startups are verified to sell carbon credits, which are purchased by companies aiming to achieve net-zero status. This commercial interest raises concerns about the potential misuse of OAE as a "Trojan horse" to gain access to carbon credits, as noted by Sarah Schumann, a commercial fisher involved in the research team.
Scaling Up and the Need for Transparency
The team behind the OAE experiment has no commercial ambitions, and their focus is on demonstrating best practices in a rapidly evolving field. They plan to model the chemical plume's long-term carbon absorption and engage with local communities and stakeholders to address concerns.
Benjamin Day shares Schumann's apprehension, noting that many companies are "racing ahead" of the science, facilitated by tech firms eager to offset their emissions.
The Way Forward
The potential of OAE as a meaningful technology is significant, but it requires careful consideration and investment. The US National Oceanic and Atmospheric Administration estimates that OAE could remove between 1 billion and 15 billion tonnes of CO2 annually at a cost of up to $160 per tonne.
Renforth emphasizes the limited options for carbon storage on our planet, urging us not to dismiss any potential solution until we have a workable plan.
In conclusion, the OAE experiment in the Gulf of Maine opens a window into a possible future where human ingenuity and stewardship could play a crucial role in mitigating climate change. While the path forward is uncertain, the need for innovative solutions is clear. As we navigate these uncharted waters, transparency, collaboration, and a deep understanding of the potential risks and rewards are essential.
