Numerous studies show the world will need to remove billions of tons of carbon dioxide a year from the atmosphere by 2050 to prevent dangerous levels of warming. For decades researchers, investors and governments have been looking for ways to sequester that carbon efficiently, and at a large enough scale to make a difference.
Planting trees, recycling and reusing, minimizing production and transitioning to a fossil fuel free economy are some of the measures we know we need to take to curb global warming. And for the past few years, seaweed has been making a name for itself as another possible solution.
Amazon and Elon Musk are amongst the big names funding new seaweed farming projects, and some others have already been underway for some time, like the sargassum farms of British company Seafields. But new research has started casting doubts on both the scalability of the seaweed solution, and its potential negative impact on the ocean’s ecosystems.
Why seaweed
It is estimated that seaweed may naturally sequester nearly 175 million tons of carbon around the world each year as it sinks into the deep sea or drifts into submarine canyons. Therefore, these projects are looking to scale that natural ability to sequester carbon by farming seaweed, in the same way we plant trees, and then sinking it to the ocean floor.
Further studies have indicated that certain types of seaweed, like kelp, have the capacity to pull down around 1 billion to 10 billion tons of carbon dioxide per year. Plus, seaweed grows quickly – much more so than trees. This makes it an apparently ideal, scalable solution to global warming.
But as researchers dig deeper, new reports are beginning to show that seaweed may not be the dream answer we once thought it was.
Why not seaweed
According to the MIT Technology Review, a study published this June “estimates that around a million square kilometers of ocean would need to be farmed in order to remove a billion tons of carbon dioxide from the atmosphere over the course of a year.”
This is a problem because there likely isn’t enough space for these large seaweed farms in places where seaweed grows easily. Also, we should be removing more than 1 billion tons: to prevent global warming levels from rising past 1. 5?C, we will need to remove up to 29 billion tons of CO2 by 2050.
Scientists are also worried about the consequences of sinking this much seaweed to the ocean floor. We know very little about the ocean floor, as it has been largely unexplored, and scientists have said they can’t begin to estimate the impact that sinking large amounts of seaweed could have on this ecosystem.
While funding from big players continues to flow towards seaweed farms, researchers continue to investigate how to maximize this idea without doing more environmental harm than good. But as with so many ‘solutions’ to global warming, it is becoming clear that there is no magic answer, but instead a handful of measures that need to work together to help the planet, and ourselves, survive.