Removing carbon from the atmosphere is a growing field of business in the fight against global warming, focusing not just on air but the ocean, the world's largest natural carbon sink. The ocean, likened to the planet's lungs, generates half the oxygen needed and absorbs a quarter of unwanted carbon dioxide, acting as a buffer against climate change. However, excess heat and carbon dioxide have made it more acidic and less effective.

Companies such as Equatic, Captura, Running Tide, and a startup called Ebb Carbon are using technology to restore ocean chemistry and enhance its natural abilities. Ebb Carbon's co-founder and CEO Ben Tarbell anticipates removing upwards of a million tons of CO2 annually within five years by improving the ocean's capabilities. Ebb's modules are set up near ocean water, like at Sequim Bay in Washington state, and use an electrochemical process to remove acid, enabling better CO2 absorption.

The technology has potential for cost reduction, especially as Ebb sells its carbon removal service to companies like Stripe, seeking offsets for net-zero goals, making it attractive to investors like Prelude Ventures. "Right now, there are very large voluntary carbon markets, large corporations willing to pay to remove carbon from the atmosphere to offset emissions in other parts of their business. Those markets alone are a multibillion-dollar market opportunity," said Gabriel Kra, managing director at Prelude Ventures.

Tarbell states that the current cost is over $100 per ton of CO2 removed, but expects this to drop as the technology scales. By coupling systems with existing infrastructure such as desalination plants and coastal power plants, Ebb Carbon can reduce costs while providing benefits. The company, also backed by Evok Innovations, Congruent Ventures, and Propeller, has raised $27.75 million to date.