CO2 storage: how Alphabet X wants to stop climate change with seaweed

Last September, Bianca Bahman was in paradise. She was snorkeling above a seagrass meadow off the west coast of Flores, a volcanic island in eastern Indonesia. But she wasn’t here for fun: As she swam across the green seabed, the researcher piloted an underwater camera suspended from some small pontoons. The stereoscopic camera captured high-resolution images from two slightly different angles, creating a three-dimensional map of the ribbon-shaped fronds sprouting from the seabed.

Bahman is a project leader at Tidal, whose team uses these specialized cameras along with image recognition technology and machine learning to better understand life under the oceans. The offshoot of Google parent Alphabet’s research company Alphabet X has been using such camera systems for several years to monitor fish in aquafarms off the coast of Norway.

As MIT Technology Review learned, Tidal plans to use its system to conserve seagrass beds in the world’s oceans and even plant new ones. This is intended to speed up efforts to allow the oceans to absorb more carbon dioxide than before – thus combating climate change. Alphabet X is a so-called moonshot factory. The Tidal Project’s mission is to advance our understanding of underwater ecosystems to advance ocean conservation efforts in the face of increasing threats from pollution, overfishing and acidification. “Our tools can open up areas that are much needed in the ocean world,” says Bahman.

Several studies suggest that the oceans could absorb a significant portion of the billions of additional tons of carbon dioxide that would need to be removed from the atmosphere each year to contain the mid-century temperature rise. However, to achieve this requires restoring coastal ecosystems, growing more algae and adding nutrients to boost plankton growth.

Tidal decided to focus on seaweed first, as it is a fast-growing plant that is particularly effective at absorbing carbon dioxide from shallow waters. These “coastal meadows,” researchers say, could absorb much more greenhouse gases if coastal communities, businesses or nonprofits help them grow.

So far, however, scientists have only a rudimentary understanding of how much carbon seaweed actually binds and what role the plant plays in regulating climate. Without this knowledge, and without affordable ways to verify that recovery efforts are actually storing more carbon, it becomes difficult to track any progress. But only then would seaweed become a valuable tool for climate protection – and could it be grown for compensatory measures by industry, for example.

Tidal hopes to solve the problem by developing new models and algorithms that translate the three-dimensional maps of seagrass it captures into reliable estimates of the carbon it stores. If successful, automated processes can follow growth in the future. This could boost emissions trading and lend credibility to the new storage tool.

The team hopes to develop autonomous versions of its tools, possibly in the form of floating robots equipped with its specialized cameras that can remotely monitor coastlines and detect biomass growth or loss. “If we can quantify and measure these ecosystems, we can drive investment to protect and preserve them,” said Neil Davé, executive director of the Tidal project.


Tidal Engineer Terry Smith tows an underwater camera system across a seagrass bed at Manjerite Beach in Labuan Bajo, Indonesia.
(Image: Agoes Rudianto)

However, some scientists remain skeptical that Tidal’s technology will be able to accurately estimate changing carbon levels in far corners of the globe. The challenges are enormous. In fact, such compensatory measures are increasingly criticized: Studies show that the benefits to the climate can be overestimated, environmental risks arise or injustices are done to the population. Davé admits that it is not yet clear how well the approach will work. That is why they have now come to Indonesia together with Australian researchers.

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