As greenhouse gas emissions continue to be dangerously large and the perils of climate change are increasingly apparent, the world is increasingly exploring ways to deliberately intervene in climate systems. A number of these ideas involve introducing substances into the atmosphere, but there are also ways to tinker with the oceans.
The oceans naturally absorb about a third of the carbon dioxide that humans pump into the atmosphere, mostly by burning coal, gas, and oil. People are exploring ways to get the ocean to take up even more of the carbon dioxide. One approach that is gaining traction is known as alkalinity enhancement. By adding limestone, magnesium oxide, or other alkaline substances to rivers and oceans, it changes their chemistry and makes them soak up more carbon dioxide.
This approach has been around for a while as a way to mitigate acid rain in rivers and has been very successful. A start-up company in Canada called CarbonRun is building a machine that grinds up limestone and will release the powder it produces into a local river in Nova Scotia. The limestone in the river will be naturally converted into a stable molecule that will eventually be washed into the seas, where it should remain for thousands of years.
Expanding this approach to oceans faces many challenges including the costs and complexities of obtaining, processing, and transporting vast amounts of limestone to where it is to be released. There are also potential environmental issues to grapple with. But CarbonRun and others are moving forward with testing the approach.
In any event, the biggest barrier to ocean alkalinity enhancement is proving that it works. That effort is underway.
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They’ve Got a Plan to Fight Global Warming. It Could Alter the Oceans.
Photo, posted May 27, 2007, courtesy of John Loo via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio
