Sequestering carbon in the briny deep is one approach. Another is to solidify the carbon into limestone or baking soda and bury it, deep. And while some big money (and political power) says removing carbon from the air is going to be required, there is opposition from folks with a range of objections; from the most common-sense: it is expensive and the cost of avoiding 1/10 degree C of warming should be laid in front of the people affected i.e. everyone. This is a number no one is talking about, even though it is basic math.* Another objection is the very real risk of severe cooling which is probably more dangerous than warming.** And then there is the unspoken objection: "but if we remove carbon I won't have my justification for mandating financial and economic rules-of-the-road and their capital, income, and cash flows."
From MIT's Technology Review, September 19:
In late January, Elon Musk tweeted that he planned to give $100 million to promising carbon removal technologies, stirring the hopes of researchers and entrepreneurs.
A few weeks later, Arin Crumley, a filmmaker who went on to develop electric skateboards, announced that a team was forming on Clubhouse, the audio app popular in Silicon Valley, to compete for a share of the Musk-funded XPrize.
A group of artists, designers, and engineers assembled there and discussed a variety of possible natural and technical means of sucking carbon dioxide out of the atmosphere. As the conversations continued and a core team coalesced, they formed a company, Pull To Refresh, and eventually settled on growing giant bladder kelp in the ocean.
So far, the venture’s main efforts include growing the seaweed in a tank and testing their control systems on a small fishing boat on a Northern California lake. But it’s already encouraging companies to “get in touch” if they’re interested in purchasing tons of sequestered CO2, as a way to balance out their greenhouse-gas emissions.
Crumley says that huge fleets of semi-autonomous vessels growing kelp could suck up around a trillion tons of carbon dioxide and store it away in the depths of the sea, effectively reversing climate change. “With a small amount of open ocean,” he says, “we can get back to preindustrial levels” of atmospheric carbon dioxide.
'No one knows'
Numerous studies show the world may need to remove billions of tons of carbon dioxide a year from the atmosphere by midcentury to prevent dangerous levels of warming or bring the planet back from them. In addition, more and more corporations are scouring the market for carbon credits that allow them to offset their emissions and claim progress toward the goal of carbon neutrality.
All of that has spurred a growing number of companies, investors, and research groups to explore carbon removal approaches that range from planting trees to grinding up minerals to building giant C02-sucking factories.
Kelp has become an especially active area of inquiry and investment because there’s already an industry that cultivates it on a large scale—and the theoretical carbon removal potential is significant. An expert panel assembled by the Energy Futures Initiative estimated that kelp has the capacity to pull down about 1 billion to 10 billion tons of carbon dioxide per year.
But scientists are still grappling with fundamental questions about this approach. How much kelp can we grow? What will it take to ensure that most of the seaweed sinks to the bottom of the ocean? And how much of the carbon will stay there long enough to really help the climate?
In addition, no one knows what the ecological impact of depositing billions of tons of dead biomass on sea floor would be.
“We just have zero experience with perturbing the bottom of the ocean with that amount of carbon,” says Steven Davis, an associate professor at the University of California, Irvine, who is analyzing the economics of various uses of kelp. “I don’t think anybody has a great idea what it will mean to actively intervene in the system at that scale.”
The scientific unknowns, however, haven’t prevented some ventures from rushing ahead, making bold promises and aiming to sell carbon credits. If the practice doesn’t sequester as much carbon as claimed it could slow or overstate progress on climate change, as the companies buying those credits carry on emitting on the false promise that the oceans are balancing out that pollution, ton for ton.
“For the field as a whole, I think, having this research done by universities in partnership with government scientists and national labs would go a long way toward establishing a basic level of trust before we’re commercializing some of this stuff,” says Holly Buck, an assistant professor at the University at Buffalo, who is studying the social implications of ocean-based carbon removal.
The lure of the oceanSwaying columns of giant kelp line the rocky shores of California’s Monterey Bay, providing habitat and hunting grounds for rockfish, sea otters, and urchins. The brown macroalgae draws on sunlight, carbon dioxide, and nutrients in the cool coastal waters to grow up to two feet a day. The forests continually shed their blades and fronds, and the seaweed can be knocked loose entirely by waves and storms.
In the late 1980s, researchers at the Monterey Bay Aquarium began a series of experiments to determine where all that seaweed ends up. They attached radio transmitters to large floating rafts of kelp and scanned the ocean depths with remote-operated submarines.
The scientists estimated that the forests released more than 130,000 tons of kelp each year. Most of the rafts of kelp washed up on shore within the bay in a matter of days. But in the underwater observations, they found bundles of seaweed lining the walls and floor of an adjacent underwater gully known as the Carmel Submarine Canyon, hundreds of meters below the surface.
Scientists have spotted similar remnants of kelp on the deep ocean floors in coastal pockets throughout the world. And it’s clear that some of that carbon in the biomass stays down for millennia, because kelp is a known source of oil deposits.
A 2016 paper published in Nature Geoscience 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.
That translates to well below the levels of carbon dioxide that the world will likely need to remove annually by midcentury—let alone the amounts envisioned by Crumley and his team. Which is why Pull To Refresh and other companies are exploring ways to radically scale up the growth of kelp, on offshore vessels or elsewhere....
....This has helped form my personal belief that carbon trading is not going to lower world temperature by even a half-a-degree.
For example, in an October 1998 article in Nature, Martin Parry (Co-chair of the IPCC's Working Group II) said the effect of the Kyoto Protocol (and it's associated carbon trading, CDM etc. [articles 6,12 and 17 of the protocol]) would be a reduction of –0.05°C by the year 2050.
Tom Wigley of the National Center for Atmospheric Research estimated that Kyoto would result in a reduction from baseline of 0.06°C to 0.21°C . (under one Kyoto scenario 0.06 to 0.11°C, under another 0.11 to 0.21).
As Warren Buffett said (in a slightly different context):"Now I'm known as a long-term investor and a patient guy, but that is not my idea of a big move."
....One of the reasons we ran Plankton Week last October—no, not as counterprogramming to Shark Week—was to refresh memories of one of the topics of conversation at all the better salons and soirées circa 2007.
Plankton Week: “Give me a half tanker of iron, and I will give you an ice age.”
The headline quote is from oceanographer John Martin during a 1988 lecture at Woods Hole Oceanographic Institution. Here's NASA's Earth Observatory archive page on the statement.
It is a bit of an exaggeration, you may need ten of those Valemax bulk carriers, currently the second largest ships in the world at 400,000 dwt (Euronav's two TI oil tankers at 441,000 dwt are bigger), to make an environmental change but what a change it would be. The orders of magnitude of carbon the iron-fed plankton would sequester are almost mind-boggling:
...Martin gathered the results of the incubation experiments and laid out the evidence in support of the Iron Hypothesis together with some back‐of‐the‐envelope calculations and presented his findings at a Journal Club lecture at Woods Hole Oceanographic Institution in July of 1988. He estimated that using a conservative Fe : C ratio that 300,000 tons of iron in the Southern Ocean induce the growth of phytoplankton that could draw down an estimated two billion tons of carbon dioxide. Then, putting on his best Dr. Strangelove accent, he suggested that “with half a ship load of iron….I could give you an ice age.” The symposium broke up with laughter and everyone retired to the lawn outside the Redfield Building for beers (from Chisholm and Morel, Editors, preface to: What controls phytoplankton production in nutrient‐rich areas of the open sea? Limnology and Oceanography, 36, 8 December 1991).
As repeated in "John Holland Martin: From Picograms to Petagrams and Copepods to Climate"
—Bulletin of Limnology and Oceanography, Wiley. 25 March 2016
....Coming up tomorrow, the Pope, and a Vancouver stock promoter.
Our series thus far:
October 27
Plankton Week: "Metal deposits from Chinese coal plants end up in the Pacific Ocean, research shows"
October 26
"Plankton Bloom Heralded Earth’s Greatest Extinction"