Scientists are exploring a controversial new method that could help slow climate change by increasing the ocean’s ability to absorb carbon dioxide. The experimental technique involves adding alkaline chemicals to seawater, a process known as Ocean Alkalinity Enhancement.
In August last year, researchers carried out a small-scale field test in the Gulf of Maine, located about 50 miles off the coast of Massachusetts in the United States. During the experiment, scientists released around 65,000 litres of the alkaline chemical Sodium Hydroxide into the ocean. The chemical was mixed with a red dye so that researchers could track how it spread through the water.
The study was conducted under permission from the United States Environmental Protection Agency and involved scientists from the Woods Hole Oceanographic Institution. The experiment was part of the Loc-Ness research project, which aims to investigate ways to remove carbon dioxide from the atmosphere and store it safely in the ocean.
According to oceanographer Adam Subhas, the ocean already stores enormous amounts of carbon in the form of dissolved bicarbonate, a compound similar to baking soda. By increasing the ocean’s alkalinity, scientists believe it may be possible to enhance this natural carbon storage process.
During the five-day test, researchers used advanced monitoring tools including autonomous underwater vehicles, ocean sensors, and research vessels to track the chemical plume. Their measurements suggested that about 10 tonnes of carbon entered the ocean during the experiment. The pH level of the seawater in the test area also rose from 7.95 to 8.3, roughly matching levels that existed before the industrial era.
Scientists involved in the project said they did not observe significant harm to marine organisms such as plankton, fish larvae, or lobster larvae during the trial. However, they noted that the short experiment did not measure possible effects on larger animals such as adult fish or marine mammals.
Supporters of the technology believe it could play an important role in addressing the global climate crisis. Some researchers suggest that if applied on a large scale, ocean alkalinity enhancement could help prevent global temperatures from rising more than two degrees Celsius above pre-industrial levels while also reducing ocean acidification.
However, critics warn that introducing chemicals into marine ecosystems could have unpredictable consequences. Environmental advocates from groups such as Friends of the Earth argue that large-scale experiments may carry environmental risks that scientists do not yet fully understand.
Experts say the debate highlights a broader challenge in climate science. While reducing greenhouse gas emissions remains the most important strategy, researchers are also exploring carbon-removal technologies to address the huge amount of carbon already present in the atmosphere.
Scientists involved in the project say more research and careful monitoring will be needed before ocean alkalinity enhancement can be considered a safe and effective climate solution.