We transformed the kitchen of a dive boat into a makeshift lab, connecting wires and tubing to craft a scientific instrument. Setting sail in Halifax Harbour, Canada, our mission was to discover if the ocean could help remove carbon dioxide (CO₂) from the air.
CO₂ is a major cause of climate change, lurking in the atmosphere and gradually warming the planet. Even a drastic cut in emissions wouldn’t halt the warming immediately, because the CO₂ already present continues to affect the climate. That’s why experts are focused on carbon dioxide removal (CDR), which aims to extract CO₂ that’s already in the air. Most current CDR efforts focus on land, like planting trees. However, land is limited. It competes with food production and can lose stored carbon through fires or deforestation, making ocean solutions increasingly appealing.
Did you know the ocean covers about 70% of Earth? It holds about 50 times more carbon than the atmosphere. Historically, there was a balance in how carbon moved between air and sea. We have added so much CO₂ that the ocean has absorbed around a third of human emissions since the industrial revolution. This has helped slow climate change, but it raises a new question: can we enhance this natural process? This exploratory field is called marine carbon dioxide removal (mCDR).
Marine carbon dioxide removal aims to reduce surface CO₂ levels in the ocean to allow for more atmospheric CO₂ absorption. One method involves adding alkaline minerals like crushed limestone to seawater. This can help decrease the ocean’s acidity while increasing its carbon absorption capabilities. For example, Planetary Technologies is working on this in Halifax Harbour.
Another approach harnesses marine life. The ocean is teeming with tiny organisms that use CO₂ for growth in what we call the biological carbon pump. By adding essential nutrients, scientists aim to boost these microorganisms, ultimately enhancing carbon storage.
However, one critical question remains: Are these methods effective? And what side effects might they have on marine ecosystems? The actions we take can be invisible, so relying on robust measurement and transparency is key. For instance, the Cassar Lab at Duke University has developed instruments to monitor changes in seawater chemistry, helping to piece together the role of microorganisms in carbon cycling.
We recently deployed a mass spectrometer in the waters near a coastal alkalinity project in Nova Scotia. This device can track dissolved gases, providing valuable insights into the ocean’s biological and chemical balances. Additionally, another tool, the Gopticas, measures photosynthesis levels in seawater samples, showcasing how scientific innovations can underpin climate action.
As we form a dedicated team to measure carbon transformations in the ocean, we aim to identify early signs of potential ecological disruptions. This is crucial because we need to differentiate between carbon that stays only briefly in the system and carbon that lasts for centuries.
Accurate monitoring is essential for two main reasons. First, it helps verify claims about carbon removal and ecological impact. Second, it ensures that public trust and support remain strong. If the ocean is to help combat climate change significantly, we need solid evidence that our methods are effective and safe for marine life.
Looking out at the turquoise water, observing the plume of alkaline flow, it’s easy to feel a sense of hope. While our efforts are small compared to the challenges of global climate change, they represent a step toward a more promising future. Innovation, care, and scientific diligence might just help us create effective and sustainable solutions.
This research is part of an ongoing initiative called Prototypes for Humanity, dedicated to addressing environmental issues through innovation.
