Xprize Winner Is Betting on Seaweed to Save the Planet

The Climate Foundation won a $1 million Milestone award from Elon Musk’s Xprize foundation last year for its innovative solutions to trapping carbon via seaweed farming. Now, the group is vying for part of the foundation’s $100 million fund alongside 14 other prize winners, but the Guardian reports that some scientists are not fully on board with their plans. The method seems simple enough. Seaweed, like giant kelp, grows quickly, but with waters warming, its future is uncertain, and production is down by 20% in the Philippines since 2011. The Climate Foundation built a giant ring in the waters there that raises farmed strands of seaweed using energy from solar panels to bring it up, where it soaks in sunlight and sucks in CO2 to photosynthesize energy twice a day. After, the ring lowers back down into cooler temperatures.

Seaweed is packed with nutrients, making it a great food source, and it has many environmental bonuses along with its ability to store carbon. It’s being formulated into eco-friendly plastic, and farmers in South Africa are experimenting with adding it to cow diets to reduce methane from their farts. For future financial viability, the Climate Foundation plans to produce its seaweed into a pesticide-free fertilizer, which is another positive environmental solution, but that plan runs into a speed bump. For seaweed to store carbon, it must act like an underwater forest. Like trees, once you chop down the seaweed, trapped carbon is released back into the atmosphere. The group estimates 20% to 40% of the crop falls to the sea floor, where it will potentially sequester carbon, but the majority of it will be harvested.

And then there’s the problem of artificial upwelling. Rising temperatures has disrupted the natural upwelling of water, a process where nutrient-rich deep water mixes with warmer surface water. Climate Foundation’s team plans to artificially induce the process via pipes, and conservationists are concerned. Forcing warmer water deeper can harm the plants and animals below, and that’s just one example in a long list of artificial upwelling’s potential effects (which include toxic algae blooms, oxygen depletion, and altering ocean currents). “In a worst-case scenario, if there was a problem with the upwelling, we can turn off the pumps and everything goes back to the way it was before,” says Climate Foundation’s founder Brian von Herzen. But German ocean research center GEOMAR says artificial upwelling may be irreversible based on simulations it’s run.

And while seaweed is a great hope for climate change, according to Hakai Magazine, there are not many definitive answers to how long it locks away carbon from the atmosphere, Research is being done to understand it more. Seaweed’s capacity to store carbon must last for at least 100 years in order to classify it as long-term carbon sequestration. But to von Herzen, trying something is better than nothing. “Whether we like it or not, we have already perturbed planet Earth,” he says. “Every time you fly in a fossil fuel-powered plane or drive a car, it’s an act of geoengineering. We know the consequences of releasing more carbon into the atmosphere, and yet we keep choosing to do it.” (More science news).