Turning Rivers into Climate Allies to Trap Carbon and Combat Global Warming

According to the New York Times, a company in Nova Scotia is developing a machine to help combat global warming by turning rivers and oceans into natural carbon dioxide (CO2) absorbers. The machine, built by CarbonRun, grinds up limestone and releases it into nearby rivers, where it interacts with CO2, converting it into a bicarbonate molecule that stays in the water and eventually flows into the ocean. This chemical transformation could trap carbon for thousands of years, preventing it from escaping into the atmosphere and contributing to the greenhouse effect.

This method, known as alkalinity enhancement, aims to accelerate a process that naturally occurs in oceans, which already absorb about a third of the CO2 emitted by human activities like burning fossil fuels. By speeding up this absorption using rivers and oceans, scientists believe they can significantly reduce the amount of CO2 in the atmosphere. CarbonRun’s first machine, which costs around $400,000, will be operating later this year in Nova Scotia’s West River Pictou.

The simplicity of the technology is a major advantage, as the river’s natural flow helps distribute the limestone and absorb CO2. The company envisions installing many such machines worldwide to help offset emissions on a large scale. Their work builds on older techniques used to combat acid rain in the 1970s and 80s, when limestone was added to rivers to neutralize acidic water and revive fish populations. CarbonRun’s founders discovered that this same method could also be effective at trapping carbon.

With climate change worsening, many scientists and entrepreneurs are exploring innovative ways to remove excess carbon dioxide from the atmosphere. Alkalinity enhancement is gaining traction because of its potential to trap billions of tons of CO2 annually. A $1 billion fund backed by tech companies like Stripe and Alphabet has already invested heavily in this approach, recognizing the enormous potential of ocean-based carbon removal.

Despite its promise, there are significant challenges ahead. While CarbonRun has proven that adding limestone to rivers can effectively trap CO2, doing so in oceans, will be far more complex. Scaling this method globally would also require massive amounts of limestone, leading to concerns about the environmental and logistical challenges of mining and transporting the necessary materials. Also, there are unknown risks associated with altering ocean chemistry. Some environmental groups have expressed their fear for the experiments and their potential effects on aquatic life.

Nevertheless, the urgency of the climate crisis has led many scientists to believe that these kinds of interventions are necessary. While the primary solution remains reducing emissions from fossil fuels, removing some of the CO2 already in the atmosphere is crucial to keeping the planet livable.

CarbonRun’s efforts are gaining momentum. In a recent deal, the company secured $25 million from Frontier to expand its limestone machines and remove over 55,000 tons of CO2 from the atmosphere.

Ultimately, scientists agree that while this idea has risks, they may be necessary to avoid catastrophic climate outcomes. Efforts like CarbonRun’s represent the intersection of innovation, environmental science, and global cooperation, as the world grapples with finding effective solutions to the climate crisis.