Lennart Bach kneels on the dock in Hobart, holding a vial of cloudy liquid that could one day help cities breathe easier. The seawater sample is part of a quiet revolution unfolding not in distant labs or global summits, but right here — in harbors, near wastewater plants, and beside wind farms. Scientists at the University of Tasmania’s Institute for Marine and Antarctic Studies (IMAS) are reimagining how we fight climate change: not with massive, planet-scale engineering, but with small, thoughtful steps that communities can take today.
For years, ocean alkalinity enhancement (OAE) was seen as a futuristic fix — a way to pull gigatonnes of carbon dioxide from the air by turning the sea into a giant sponge. But that vision overlooked real-world complexity. Now, in a new paper published in Nature Reviews Earth & Environment, researchers like Bach argue it’s time to bring OAE down to earth. Instead of waiting for global solutions, local governments and towns could start using it now to tackle their own emissions.
Here’s how it works: when you add alkaline minerals like silicates to seawater, they react with CO₂ and turn it into bicarbonate — a stable form of carbon that can stay locked in the ocean for thousands of years. It’s not magic; it’s chemistry nature has used for millions of years. Rivers do it naturally, carrying weathered rock into the sea and helping regulate Earth’s climate. The IMAS team says we can mimic this process responsibly, right where people live.
A city could use waste heat or excess wind power to boost alkalinity in coastal waters. A port might neutralize its shipping emissions by releasing treated minerals nearby. Even domestic wastewater — a source of carbon — could be paired with silicate runoff to cancel out its footprint. These aren’t hypotheticals. They’re practical ideas being tested now in places like Hobart, where divers collect sediment samples to study how marine life responds.
But there are caveats. Adding material to the sea changes more than just pH. Some methods may stir up sediments or introduce trace metals. That’s why lead author Lennart Bach stresses the need for local testing: “Understanding how these perturbations interact with marine life is critical,” he says. One size doesn’t fit all. What works near a rocky shore may harm a coral-lined bay.
Still, the potential is vast. Dr. Tyler Rohr points out that increasing average ocean alkalinity by just 2% could store all 2,660 billion tonnes of CO₂ humanity has ever emitted. The challenge isn’t capacity — it’s delivery. We need smarter models that account for local ecosystems, currents, and chemical feedbacks.
By starting small, communities can build trust, refine techniques, and scale only where it makes sense. This isn’t about fixing the whole planet overnight. It’s about giving towns, cities, and regions a tool they can actually use — today.