Scientists pour chemicals into the ocean to stop global heating

An ocean geoengineering trial administered by a team of American scientists released 65,000 litres of sodium hydroxide into the Gulf of Maine. The experiment centred around two goals: attempting to reduce global warming, and countering the damaging ocean acidification caused by excess absorption of CO₂.

Adam Subhas, the lead oceanographer on the research team, announced at the AGU Ocean Sciences Meeting on 25 February 2026 that early results from the test were positive. There was a significant impact on CO₂ uptake, with between 2 and 10 tonnes of CO₂ removed from the atmosphere over 4 days.

The sodium hydroxide was tagged with red dye as a means of displaying the impact, by giving the area a temporarily scarlet appearance. Despite perhaps looking concerning, the overall impact of the test on marine organisms appeared very encouraging.

The US National Oceanic and Atmospheric Administration estimates it would remove between 1-15 billion tonnes of C02 annually

Ocean alkalinity enhancement (OAE) boosts the natural alkalinity of the ocean to encourage it to absorb more carbon, which removes excess carbonic acid formed by the reaction of carbon and water. The ocean’s carbonic acid levels have increased by over 30 percent since the Industrial Revolution, and this acid is destructive to marine life, particularly organisms with calcium carbonate shells such as plankton or coral. The acid disintegrates their structure, killing these creatures and disrupting entire ecosystems.

In contrast, the experiment found no evidence of harm to marine life, displaying the evident benefits of the trial. While the experiment was relatively small scale, if it were to receive more investment, the US National Oceanic and Atmospheric Administration estimates it would remove between 1-15 billion tonnes of C02 annually at the cost of 160 dollars per tonne. This could be a significant step towards countering global warming.

The OAE approach may be favourable to other forms of carbon capture as the emissions do not need to be permanently stored. This carbon is turned into bicarbonate ions, with the carbon inside locked away for an estimated tens of thousands of years. The experiment may thus have uncovered a more permanent solution for countering CO₂ emissions, one not reliant on limited space.