The world’s oceans are emerging as one of the most powerful natural allies in the fight against climate change. Scientists are now exploring ways to strengthen the ocean’s ability to absorb carbon dioxide from the atmosphere, opening a new frontier in global climate action.
Researchers are studying innovative methods to increase the ocean’s capacity to store carbon for long periods, a process known as marine carbon dioxide removal (mCDR).
The ocean already plays a massive role in regulating Earth climate. Covering nearly 70 per cent of the planet’s surface, it stores around 50 times more carbon than the atmosphere. Since the industrial revolution, oceans have absorbed nearly one-third of human generated carbon dioxide emissions, significantly slowing the pace of global warming.
However, scientists warn that current efforts such as reforestation alone may not be enough to address rising greenhouse gas emissions. Land based carbon removal projects face challenges including deforestation, wildfires, limited land availability and competition with agriculture. As a result, attention is increasingly shifting toward the oceans.
Researchers in Halifax Harbour, Canada, are currently testing one such ocean-based climate solution. Scientists have been adding alkaline minerals such as limestone and basalt into seawater to reduce ocean acidity and increase its ability to absorb carbon dioxide from the air. The project is being developed by Planetary Technologies.
The basic principle is simple when carbon dioxide levels at the ocean’s surface decrease, the sea naturally absorbs more carbon dioxide from the atmosphere. Scientists hope this process could help store carbon in stable forms for centuries.
Another approach relies on marine biology. Tiny ocean organisms absorb dissolved carbon dioxide through photosynthesis. When these organisms die, part of the carbon sinks into deeper ocean layers through what scientists call the “biological carbon pump.” Researchers are examining whether adding nutrients to seawater could safely increase this natural process.
To monitor these experiments, scientists from Duke University are using advanced instruments capable of detecting subtle chemical changes in seawater. One device, a mass spectrometer, measures dissolved gases and helps researchers understand how carbon moves through marine ecosystems. Another instrument called the Gopticas tracks photosynthesis levels in seawater samples to evaluate ecosystem health.
Scientists say accurate monitoring is critical before such projects can be expanded globally. They stress that carbon removal claims must be backed by scientific evidence and environmental safety assessments.
Researchers also acknowledge concerns about possible ecological impacts. Large scale changes in ocean chemistry or marine ecosystems could create unintended consequences if not carefully studied and regulated.
Despite these challenges, scientists believe marine carbon dioxide removal could become an important climate tool in the coming decades. With global temperatures continuing to rise, the ocean’s natural ability to absorb carbon may offer a valuable opportunity to slow climate change while the world transitions toward cleaner energy systems.