It was a throwaway line about “an inadvertent fish farm” in a book filled with stories about cutting edge, big idea, save-the-future, deep tech innovation. It was the invention that never made it out of the lab.
It was the story I couldn’t stop thinking about.
Pablos Holman, a self-styled outlaw hacker and salsa-dancing enthusiast famous for dressing in Johnny Cash black and a signature pair of snake-eyes tinted glasses, is in the business of turning science fiction into science fact. He is both an inventor and investor, a true-believer that the way to solve pretty much everything involves the pairing of technology and capitalism. In Deep Future, his new book (also the name of a companion podcast), Holman sings the praises of nuclear fission, silicon-free computer chips, making clothes with robots, AI and adhesives, self-healing cement and much more.
Of course, not all the big ideas work out (see killing mosquitoes with lasers), but they push the boundaries of imagination and the possible.
Fifteen years ago, when Holman worked at Intellectual Ventures, a spectacularly well-funded think tank / inventors’ playground / investment firm founded by former Microsoft CTO Nathan Myhrvold, he was part of a team charged with coming up with answers to humanity’s most daunting challenges. That included solving hurricanes: Could they find a way to make the most powerful storms on the planet a little less powerful and thus a little less deadly?
Hurricanes draw strength from the heat in the oceans above which they form. In general, the more heat energy, the faster they spin and the more water / water vapor they are able to swirl into the storm. In a warmer, climate-changed world with more frequent and increasingly intense atmospheric and marine heatwaves, hurricanes have more fuel. Holman’s team reasoned that if the surface waters of the oceans could be cooled down, it might be possible to turn a would-be Category 5 storm into Category 3. That is still a plenty big storm, just not quite as big.
For inspiration they looked an invention from mid-1970s to capture wave energy called Salter’s Duck. The Duck, named after legendary engineer, Stephen Salter, looks a little like a duck in profile as it bobs up and down in the water and was developed in response to the global energy crisis sparked by the 1973 Arab Oil Embargo. When the embargo was lifted and oil prices went down, funding for the Duck was scrapped.
The video below explains the physics of the Duck. It is also a fascinating window into what cutting edge science looked like a half century ago:
With a hat tip to Salter’s Duck, Holman’s team invented the Salter Sink. But instead of generating energy, the Sink uses waves to circulate water. A large circular ring at the surface is designed to function of a kind of beach over which waves of warm surface water crash. Once captured in the center of the ring, this warm water is pulled down a 500’ tube where it spills out into water that is much, much colder. As the warm water works its way back up to the surface, it loses heat.
“One of these things could affect about ten gigawatts of thermal energy transfer. Just astounding,” writes Holman. “It would bring the temperature of the ocean surface down by a couple of degrees for about a square kilometer.”
“…Our design was to be made with recycled truck tires, some cement, and polyethylene sheeting, like a Hefty bag. You might need a couple of thousand of these things out in the Gulf, but the cost would be dramatically less than the damage from a hurricane. Maybe tens of millions rather than billions of dollars. Holy shit, we could save so many lives and prevent so much damage and suffering.
We got busy doing computational models of the wave-pumping action and the thermal effects. We built a wave tank and a miniature Salter Sink to test in real life. We filmed it all with a thermal camera to see exactly how the mixing would go. Everything checked out perfectly.
That was fifteen years ago, and still no Salter Sink exists. It is the simplest thing we’ve ever invented. No computer chips, no chemical processes; just a big dumb tube in the ocean. The only negative consequence anyone has been able to come up with is that a barge might bounce off it now and then. The thing even brings nutrients from the cold water up into the warmer water, promoting the growth of plankton, which feeds fish. It is an inadvertent fish farm…”
A BUG OR A FEATURE? ON WHALES, CARBON AND CORAL
Holman’s team probably didn’t realize it, but this simple device—“just a big dumb tube in the ocean” to circulate ocean water vertically, bringing nutrients to the surface and feeding plankton blooms—is a biomimic of a whale.
“… During its life, which can last as long as century, a whale processes vast amounts of carbon as it dines on krill and plankton, the tiny organisms at the base of the marine food chain that collectively absorb around 40 percent of annual carbon dioxide emissions. Nutrient-rich whale poop, in turn, nourishes plankton, so the more whales, the more plankton, the more CO2 absorbed, and around it goes.
In death, a “whale fall” becomes a decades-long feast for dozens of species, a whale-size speck of astonishing biodiversity in the crushing darkness of the abyss.
…Today, there are simply fewer whales left to fall thanks to the industrial-scale hunting of the 18th and 19th centuries.”
— J.A. Ginsburg, When Life Hands You Seaweed
Although it may be species other than whales dining on Salter Sink plankton blooms, any increase in biodiversity would lead to more cycling of atmospheric carbon, which would be sequestered in food chains. The more biodiversity and the more complex the food chains, the longer the carbon would stay Earth-bound. One of the best carbon sinks of all is life itself.
At scale, this could help bring down atmospheric CO2 levels, which would cool down the planet, leading to cooler oceans and less fuel for hurricanes.
The root problem with hurricanes isn’t warmer oceans, but rather what is making oceans increasingly balmy. Part of it is chemical: greenhouse gases. But part of it is biological. Earth is a living planet defined by countless, endless cycles of gases, nutrients and water; by food chains, micro to macro, predator and prey.
The Gaia hypothesis looks at the interplay of Earth’s living and non-living components and how they create the stable, self-regulating conditions favorable to life. Nature is constantly trying to find balance. Seen through this lens, it is easier to understand that hurricanes, like all storms, are about restoring equilibrium, driven by the difference between warm and cold, dry and wet, high pressure and low. It makes sense that the hotter the planet, the stronger the storms. Hurricanes circulate water, bringing colder water to the surface and aerating marine “dead zones.” Since colder surface waters mean weaker hurricanes, a self-regulating feedback loop is in play. These storms also bring nutrients to the mangrove forests, coral reefs and wetlands that protect land from the full brunt of a hurricane’s force.
It is all of a piece.
•••••••••••••••••••
Holman’s team ultimately gave up on the Salter Sink because no one could figure out a business model.
“People think an insurance company would want to build it, but that would be economic suicide for them because of the free rider problem. If Allstate pays to build it, then State Farm gets the benefit for free, and Allstate’s higher cost makes it uncompetitive. People think a government would want to build it, but in case you haven’t been paying attention, most contemporary governments seem to suck at doing any kind of large-scale infrastructure projects these days.
—Pablos Holman, Deep Tech: Creating Technology that
But what if the clever hammer—the “big dumb tube”—they built was going after the wrong nail? What if instead of trying to cover the oceans with Salter Sinks, a handful were strategically placed where they could make an immediate, life-or-death difference?
Lowering the water temperature closer to shore, even only a few degrees, might give coral reefs—now under near-constant siege by marine heat waves—a fighting chance. When water gets too warm, the colorful symbiotic algae that live within corals pack up and flee for their lives, leaving their hosts defenseless against an invasion of harmful algae and bacteria. What was once a colorful underwater garden teaming with fish and crustaceans and octopuses and turtles and iguanas—the ocean’s nursery—is transformed almost overnight into a bleak, near-lifeless landscape.
“…During heatwave-induced mortality events, exposed coral skeletons are, within days, encased by a complex biofilm of algae and bacteria. Their metabolic activity accelerates calcium carbonate dissolution to levels that significantly exceed documented accretion rates of healthy corals in normal seawater conditions. This bioerosion reduces the coral’s skeletal density and hardness, and increases porosity…”
—NOAA: Rapid coral decay is associated with marine heatwave mortality events on reefs
The collateral damage is staggering. The loss of fish nurseries means the loss of fisheries and the food and livelihoods they provide. The frail, brittle bones of what’s left of the ravaged corals are are no match for hurricane-driven waves. What was once an effective storm barrier is no more.
But what if Salter Sinks could help?
In the 15 years since Holman’s team worked on Salter Sinks, then got stumped looking for a business model, there are now “blue bonds” and “blue carbon credits” to support marine restoration. Prince William’s prestigious Earthshot Prize has teamed up with Builders Vision, Bloomberg Philanthropies, Breakthrough Energy, Bezos Earth Fund, Temasek Trust and others to provide funding to scale and accelerate the development of ocean-focused initiatives all over the world.
There are companies such as Coral Vita breeding climate-hardier corals and several groups developing artificial reefs to kickstart the re-establishment of natural reefs.
But if the water is too hot, any gains will be short-lived.
It is even possible insurance companies, or their foundations, would provide funding. In a climate-changed world, catastrophe bonds have become a booming business. The Nature Conservancy recently teamed up with reinsurance giant Munich Re to provide parametric coverage for Hawaiian reefs. It would make sense for insurance companies to invest in technologies, especially a cheap one made from “recycled truck tires, some cement, and polyethylene sheeting,” that could help mitigate their risk.
Protecting the health and productivity of coastal waters, while helping natural storm barriers (mangroves forests, coral reefs and wetlands) stay robust, Salter Sinks could help lessen the damage from hurricanes—which was the original goal.
Maybe the time has finally come to put this “big idea, save-the-future, deep tech innovation” back into the mix.
WAVE HELLO!
In the fifty year since the first Salter’s Ducks bobbed in he water, wave energy technologies have improved dramatically. Although not nearly as well known their renewable siblings solar and wind, 40% of the world’s population lives within 65 miles of a coast, so wave power has the potential to play an important role in a clean energy future.
In a new report on “oceans as infrastructures for materials and energy,” Paris-based materials research company Tocco listed several promising ventures, including:
MeyGen Tidal Project (Scotland): the world’s largest operational tidal stream array.
Minesto (Sweden & Faroe Islands): undewater tidal kites
Orbital Marine Power (Scotland): floating tidal turbine platform
In addition, there are several sites around the US testing wave energy projects.
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