The most pressing threat to whales, plankton, life on Earth and civilization as we know it is not wind farms or preliminary studies on ocean alkalinity enhancement, but rather the very crisis both are intended to help resolve.

The repeated failure of world powers to sufficiently curb greenhouse-gas emissions has forced humanity into a bizarre pantomime. It feels like dancing around a wildfire with butterfly nets in hand, trying to catch every stray ember and flake of ash while halfheartedly throwing teacups of water onto the flames. Within the confines of this... See more

The Indigenous peoples of western North America farmed clams in walled gardens along the shore to which they routinely added crushed shells. Research has since confirmed that doing so raises the pH of the water, improving the growth and survival rates of juvenile shellfish and, in combination with other benefits of the gardens, yielding two to four... See more

Although this innate resilience helps keep Earth stable on geologic time scales, it operates far too slowly to save extant life from the current rates of warming and acidification. Ocean alkalinity enhancement is an attempt to emulate and accelerate the planet’s stabilizing feedback loops so that they occur in a matter of decades.

As rain falls on land, it breaks down rocks, including ones like basalt and limestone, which contain alkaline minerals. Rivers carry the minerals liberated from these rocks to the ocean, where they nourish calcifiers and bind to dissolved carbon in seawater, reducing its acidity and allowing it to absorb more carbon from the atmosphere. In tandem,... See more

Earth as a whole is not helpless in the face of climatic and chemical volatility, however. It has powerful self-stabilizing processes. When carbon floods the atmosphere, making the planet hotter and stormier, its carbon-sequestering processes speed up.

“If we’re serious about carbon-dioxide removal, it’s going to be the largest thing humanity has ever done,” says David Ho, a professor of oceanography at the University of Hawaii at Manoa and an expert on the marine carbon cycle. “It really should be something that governments pour effort into, like the Manhattan Project.”

Limiting warming to under two degrees Celsius requires the capture and sequestration of perhaps seven to nine billion tons of carbon dioxide each year, in addition to steep reductions in emissions. Experts estimate that ocean alkalinity enhancement alone could remove somewhere between one and 15 billion tons.

Since the advent of the industrial age, the oceans have absorbed about one-third of humanity’s heat-trapping carbon emissions. Were it not for that immense buffer, the planet would be substantially warmer and more tempestuous than it is today. As carbon dioxide from the atmosphere dissolves into the ocean, however, it reacts with seawater to form... See more