Climate change: Can an enormous seaweed farm help curb it?

Imagine a immense seaweed workplace the size of Croatia floating successful the South Atlantic betwixt Africa and South America.

Spinning successful a earthy water eddy, it sucks a cardinal tonnes of c retired of the ambiance each twelvemonth and sinks it to the water level retired of harm's way.

Far-fetched? Maybe. But a British businessman plans to person this up and moving by 2026.

Scientists accidental reducing the world's emissions astir apt won't beryllium capable and that c seizure volition beryllium important to limiting planetary warming. But carbon seizure schemes person truthful acold been comparatively low-scale and seen constricted success.

If they are going to work, they request to beryllium bold, big, and charismatic to investors.

Businessman John Auckland believes helium has conscionable specified an idea. He wants to exploit what helium calls "the wondrous properties" of the floating seaweed sargassum. He's assured his Seafields floating workplace volition gully capable CO2 from the aerial to mean the effects of clime change, portion besides earning its backers c credits.

At 55,000 sq km (21,200 sq miles) Auckland is reasoning big. It needs to beryllium immense to enactment a dent successful the 50 gigatonnes of c dioxide we pump into the ambiance each year. A gigatonne is simply a cardinal tonnes: the magnitude of c Auckland's mega-farm aims to seizure annually.

The task is presently road-testing its exertion successful the Caribbean and Mexico, and is inspired by the ideas of Prof Victor Smetacek, a marine biologist. Described by Seafields arsenic their Scientific Founder, helium has agelong been fascinated by the imaginable to turn seaweed successful tremendous rotating water currents known arsenic gyres.

"They cod each kinds of worldly successful the middle," helium says. "The champion known examples, of course, are the integrative garbage that is accumulating successful the mediate of the subtropical gyres."

In the aforesaid mode these elephantine eddies trap islands of floating plastics, Seafields plans to hem successful its harvest of sargassum.

"The gyre conscionable stops the sargassum from escaping," explains John Auckland. "As agelong arsenic we make the close conditions for it, it volition lone turn there. If immoderate escapes from our farm, it volition conscionable dice disconnected oregon conscionable neglect to proceed growing."

He had amended beryllium right. Sargassum has plagued the Caribbean's tourism manufacture for decades. When it washes up connected the coast, its rot gives disconnected a foul stench. Not the champion mounting for relaxing connected a formation towel.

But Seafields is assured this volition not hap with their seaweed. It says immoderate that escapes from the workplace should beryllium starved the nutrients the squad plans to syphon up from the water depths to provender their crop.

Because of evaporation from the subtropical prima beating down connected it each day, the aboveground h2o trapped successful gyres is precise salty and debased successful nutrients. It is wherefore Prof Smetacek calls gyres "the oceans' deserts".

Yet, arsenic these deserts dilatory turn, they glide implicit a colder, nutrient affluent water furniture that the prof wants to gully to the aboveground to prolong the sargassum.

"If you were to link the nutrient rich, heavy h2o with pipes," explains Prof Smetacek, "bring that h2o up from the bottommost and fto it lukewarm up, past it volition travel up by itself and proceed flowing forever."

The squad is investigating their exertion successful aboriginal 2023. It volition beryllium a nail-biter. While archetypal theorised backmost successful 1956, the brackish fountain has successfully been recreated, but obscurity adjacent the tremendous standard Seafields plans.

If the brackish fountain does enactment to scale, Prof Smetacek predicts a bumper harvest of sargassum.

"They person tremendous maturation rates. They treble their biomass each 10 days," helium says. "The bully happening astir seaweed is that you tin harvest it with a harvester harvester."

Prof Smetacek envisages floating harvesters volition bale the harvest up and past nonstop it down to the inert depths of the oversea floor, wherever determination is truthful small oxygen the bales volition not rot. The c they incorporate volition stay fixed successful the seaweed's structure. Tests are ongoing, but the squad envisages they tin sequester captured c for hundreds, possibly thousands of years.

Seafields' fiscal backers anticipation sargassum volition interval wealth their mode too. They program to merchantability credits for captured c connected the world's c markets. These credits let businesses similar airlines that cannot easy chopped their emissions, to bargain up c reductions made elsewhere.

Carbon marketplace critics kick the onward unreserved to monetise CO2 seizure has led to backers overselling technologies that yet autumn abbreviated of their stated aims. Which begs the question: volition Seafields' promising program successful the laboratory really enactment erstwhile released into the wild?

Dr Nem Vaughan, subordinate prof successful clime alteration astatine the University of East Anglia says: "I'm a boring scientist, [I'd want] much data, much research, earlier I'd wholeheartedly accidental that you're going to get that benignant of gigatonne-scale removal happening."

Dr Vaughan is besides disquieted astir a strategy that itself could person profound impacts connected biologic systems. Can Seafields incorporate truthful overmuch perchance damaging seaweed retired successful the South Atlantic? Is the brackish fountain robust capable to upwind each conditions?

"People wouldn't beryllium precise happy," she says, "if tonnes of integrative tubes got acceptable adrift by a large Atlantic tempest similar we've conscionable had".

She says determination are little technologically challenging ways of giving quality a nudge, specified arsenic increasing much trees and hedgerows and protecting habitats specified arsenic peatlands that people clasp carbon. But, archetypal and foremost, she says: "We request to not instrumentality it [CO2] up there. Just permission the fossil fuels successful the ground, team. It's an atrocious batch easier to conscionable permission it successful the crushed than it is to effort and seizure it erstwhile it's out."

John Auckland concedes immoderate elements of the process aren't yet proven, but believes it's worthy the gamble.

"I spot acold much risky things connected a regular ground that investors are consenting to enactment their wealth into," helium says.

"We tin really marque important gains successful solving the clime crisis. You can't not instrumentality this risk, due to the fact that if everyone thought that way, no-one would beryllium moving connected solutions of this scale."