How to Save the Climate Despite Everything
Concerning seaweed and its many uses.
For 30 years, we’ve been saying we need to curb emissions to fight climate change—and for 30 years, emissions have kept rising every single pandemic-free year. With the Trump administration determined to drive a stake through the heart of climate policy, a lot of environmental activists are feeling dejected. I’m not. Because the old strategy was failing, and we were desperately in need of new ideas anyway. Could this Trump Shock be the thing that forces a rethink?
I hope so.
IPCC scientists have known for years that the Paris Agreement targets couldn’t be met without taking large amounts of carbon out of the atmosphere—that is, removing what’s already in the air rather than simply preventing fresh emissions. It was the sort of thing everyone knew and nobody wanted to call attention to. With the Trump Shock, gigaton-scale carbon dioxide removal is moving from quietly-acknowledged-necessity to hair-on-fire-imperative.
Plenty of methods have been proposed to do this. Most of them probably won’t scale. But one of them could.
It’s called marine Carbon Dioxide Removal (mCDR). This may be the first time you’ve heard of it. But it won’t be the last.
The logic for mCDR is straightforward. The only way we know to take carbon dioxide out of the air at scale is through photosynthesis: as some high school teacher probably tried to explain to you, plants absorb carbon dioxide and release oxygen as they eat sunlight. That’s what photosynthesis is. We’ve always known we can use it to capture CO2. The question is how.
The Little Brain version of this idea goes: “plant lots of trees!” That sounds nice—it is nice—but it’s not a climate-scale solution. People emit so much carbon dioxide now that there’s just not enough land for the number of trees you’d need to plant. Go down this path and trees start displacing farmland, but then what are we going to eat?
That’s why the Galaxy Brain version of the idea is to do it someplace we’ll never run out of room: the open ocean. Because oceans are vast—twice as big as the land. Everybody knows that. What fewer people know is how much of the ocean is barren. “Marine deserts”—stretches of water where not much of anything lives—cover more than a quarter of the Earth’s oceans. That’s more than twice the size of Asia.
Before industrial fishing and whaling, these oceans hosted much more life than they do now. When the first European explorers sailed to North America, they could lower baskets into the North Atlantic and pull them up just full of cod. On his trip on HMS Beagle, a young Charles Darwin reported that vast stretches of the Southern Ocean were literally orangish-brown from what we now know were huge banks of krill.
Ocean biomass has been in steep decline since the second half of the 19th century, when people started getting good at hunting whales. That’s no coincidence. By feeding in the ocean depths and then, well, pooing near the surface, whales fertilized phytoplankton blooms that fed the krill and other organisms that the whales would ultimately eat. This “whale pump” was key to making the whole thing work. Without it, phytoplankton biomass totals fell by half between 1969 and 2019. This is our mess. We need to fix it. We stopped mass-scale whaling almost 40 years ago, but the whale pump never recovered.
It can’t, unless we help it.
mCDR, then, isn’t just about taking carbon out of the atmosphere. It’s first and foremost about restoring oceans to the condition they were in before humans went and wrecked them.
But what kinds of plant life should we be focusing on? And where, exactly? There are a few different approaches. Some groups want to target “macroalgae”: seaweed big enough to see with the naked eye. Other groups are focused on “microalgae”: microscopic photosynthetic organisms. Both make a compelling case.
The Case for Big Seaweed
Seaweed is a wondrous thing. For one, it grows incredibly fast: when it comes to piling on CO2-guzzling biomass, no photosynthesizer can compete with seaweed. Under the right conditions, some species can undergo cell division four times in a single day—they can go from one cell to 16 within a single 24 hour period.
For another thing, seaweed is yummy—living in Japan, I eat some almost every day. It’s nutritious, and not just for people. Seaweed is an established source of feed for farm animals. Some seaweed species have been shown to reduce the methane cows produce through digestion, so that’s another climate win. And several teams are now exploring ways to turn the stuff into fuel, too.
But these kinds of approaches only scratch the surface: seaweed is incredibly versatile. It creates thick, tough cell walls whose potential uses technologists are only now starting to understand. Some researchers are working on turning seaweed biomass into building materials: buildings made from seaweed-derived bio-polymers would be carbon sinks themselves, locking CO2 away in their own structures. You can sell this stuff, which means you can fund this approach.
Pushed hard enough, you could solve a startling portion of the climate crisis just by focusing on scaling seaweed farming. Some groups are out there doing exactly that right now. But it’s not the only approach.
The Case for Little Seaweed
The alternative is to go microscopic.
Virtually every drop of water in every ocean, sea, lake, river, stream, and pond everywhere on earth hosts microorganisms that eat sunlight. And not one or two, but thousands of them. We seldom think about them because we can’t see them with the naked eye, but they’re everywhere.
They’re at the base of the entire ocean food chain, and though each of them is tiny, there are roughly a billion billion billion of them (that’s a one followed by 27 zeros.) At least half of the oxygen you breathe is made by these tiny marine photosynthesizers; they’re the key reason oceans are such an efficient carbon sink. But plankton populations are in trouble, and have been for a long time: as their numbers fall, the ocean’s ability to absorb carbon degrades.
That’s why stimulating their growth is probably the most intriguing idea in climate science today.
In marine deserts, phytoplankton—the gnarly name scientists give to tiny sea plants—often have every nutrient they need except one: iron. Field experiments have confirmed that you can stimulate huge phytoplankton blooms just by dissolving tiny amounts of iron fertilizer in the water. There was a boom in this sort of research in the 1990s and 2000s, and the theory of the case is now pretty much proven.
Plus, we have many documented cases of nature fertilizing phytoplankton blooms with iron: Hydrothermal vents do it, Saharan dust storms do it, volcanoes do it, even the ash from forest fires does it. In warmer waters, bioavailable nitrogen is a second limiting factor, which is why some scientists are working on strategies to fertilize nitrogen-fixing plankton. Some amazing research is getting done in this area.
Some of the carbon that plankton absorbs will stay out of the atmosphere for years, some of it for decades, some for centuries and some for millennia. Figuring out exactly how long bio-sequestered carbon will stay out of the air under which circumstances remains the major unanswered question in the field.
One group of scientists, led by University of Southern California oceanographer Dr. Seth John, is working on a trial designed to mimic a system of hydrothermal vents near Tonga that has been naturally fertilizing phytoplankton blooms in the South Pacific for years. He estimates that, scaled up, that approach could ultimately absorb up to 4 billion tons of CO2 per year: almost as much carbon dioxide as the entire United States emits.
Other groups are proposing trials to mimic the phytoplankton blooms that volcanoes fertilize. Still others want to mimic the migration patterns of whales. With a bit of funding, we could see demonstration projects as early as this year. Scaling up will take several years. We have a lot to learn. It will take careful tinkering with fertilization protocols to minimize risks and side impacts, and there’s no guarantee it will all work in the end. But it might. If it does, seaweed, big and small, could be capturing much of the carbon people emit within a decade or two.
There’s no question that the ecological impact of all this new plant life on the oceans would be profound. But it wouldn’t be unprecedented: oceans have hosted much more life than they now do many times in the past. And the ecological impact of letting CO2 build up in the atmosphere unchecked would be bad at best, catastrophic at worst.
The climate movement has been so focused on reducing emissions for so long, it’s lost all sight of the fact that there are other ways to bring carbon dioxide concentrations under control. In a world where 70% of emissions and the vast bulk of emissions growth come from developing countries, focusing on emissions from people in rich countries never made any sense as a climate strategy anyway.
Marine Carbon Dioxide Removal was always something we were going to have to do. In the new Trump era of not even pretending to try to curb emissions, the urgency to act is all the greater.
And, right now, seaweed might be our best hope.
Quico Toro is Director of Climate Repair at the Anthropocene Institute, a contributing editor at Persuasion, and writes the Substack One Percent Brighter.
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I got some news for you. The “climate” doesn’t care what you think or do - it’s too busy being massive, complex and ungovernable, in addition to undergoing its own changes which humanity affects only at the margins. Pollution, on the other hand, from littering by individuals to discharges from industry to overall waste management impacts our immediate environment and our quality of life and should be our focus.
And if you live on a speck of earth in the middle of a vast ocean, you’re not going to be inundated because Americans like driving F-150s - it’ll be because you live on a speck of earth in the middle of a vast ocean.
Same goes for any coastal habitation (I’m looking at you, Eastern Seaboard and Gulf of America (first time I’ve been able to write that, and it’s glorious) communities, Miami, et al.). The waters come because the ocean. Period.
Climate change is constant, and much like the poor, floods, droughts, tornadoes, hurricanes, and the natural calamities we call force majeure (acts of God) will always be with us. They’re a built-in reminder of how small we are.
Now pick up that Macdonalds wrapper you just “accidentally” dropped, quit throwing your cigarette butts goddamn everywhere, and quit rolling coal while you’re out cruising. And you hippies, Gaia is not one big composting pile, your “environmental protests” generate far more garbage and environmental degradation than that pipeline ever will, and if you insist on making fools of yourselves by throwing soup on classic artwork or blocking rush hour traffic, you had better not have one goddamn iota of petroleum-derived material on your person or in your household, or you deserve to be run over by that F150.
You know what, check that. If you’re a climate apocalypse “leave it in the ground” type activist, fuck you. Though I’ll don a grass skirt and coconut bra after several mai-tais at the poolside bar (never goes out in style), I am not going to live in an earthen hut and scratch out a living like a dust bowl chicken
There is no "saving the climate". You liberals and climate crisis cultists are not Gods. Climate is nature. You cannot control nature.
However, what you can do is to advocate for good stewardship of the environment. You can advocate for government support of technological R&D to improve green sustainable energy.
And you can STOP YOUR IRRATIONAL OPPOSITION TO NUCLEAR POWER.
Lastly, you can advocate for adaption measures as climate changes and will always change and adaption measures are supported by both climate crisis believers and those that think it is bunk.