Seaweed, Sequoias, Cement and Soybeans: How We Capture Carbon

The world warms, thanks to the atmosphere’s always-expanding volume of heat-trapping carbon dioxide. As President Biden said during a climate summit in Washington in April, “This is the decisive decade. This is the decade that we must make decisions to avoid the worst consequences of the climate crisis.”

Avoiding C02 emissions altogether stands as an important strategy. We need to fix our transportation sector, for example. It accounts for about one-fifth of global carbon dioxide. Advances in battery technology offer one tool to help reduce transportation’s C02 footprint. Buildings need attention, too; they are responsible for one-third of greenhouse gas emissions in the United States. Creating structures out of things other than energy-intensive steel and concrete, and relying on green energy for electricity, would help ratchet down their emissions.

These represent just two challenges. Our carbon-related burdens, however, are myriad. Our arsenal of tools needs to be vast.

One area of promising R&D and activity, with many powerful instruments, revolves around catching carbon before it reaches the atmosphere, and storing it.

When you hear terms like “carbon capture,” “carbon sequestration” and “carbon removal,” this is what is being referenced.

Following is a spectacle of editorial attention to carbon capture. It’s engaging! Lively! Interesting! And as with most spectacles, it’s also elaborate. Kinda’ long. At the end of the deep dive into biological carbon capture, we offer tips for YOU, reader, about how to mitigate your own carbon footprint on this grand Earth. If you want to skip ahead to the Earth-saving tips, click the button below. However, we think you should wade into this stimulating mountain stream and follow it to its conclusion.

From troposphere to space

One occasional misconception regarding the atmosphere is that it is exclusively “up there” somewhere; that C02 gets trapped in some band of air encircling earth like a girdle, which traps heat rising from below.

In fact, the atmosphere begins at our feet (a part of the atmosphere called the troposphere) and extends up through the stratosphere (which spans between 7 to 31 miles beyond Earth), the mesosphere (31 to 50 miles), the thermosphere (50 to 440 miles) and the exosphere (440 to 6,200 miles). 

Carbon dioxide figures into the chemical composition of all of these layers of the atmosphere. If humans manage to reduce the atmosphere’s concentration of C02, the achievement will affect chemical compositions from the ground all of the way up to the edge of space.

Another important consideration: What is carbon dioxide?

Plants belch oxygen after C02 feasts

The gas carbon dioxide, which contains one part carbon and two parts oxygen, is essential for life on earth. The most salient of C02’s important roles is its centrality to plant life. Plants combine carbon dioxide and water to produce carbohydrates — they essentially feast on C02 and water. And the byproduct — the waste, essentially — of this consumption is oxygen, which serves as a key foundation of human life. When humans take breaths, oxygen moves from lungs to blood; some of it gets exhaled. Humans also exhale the carbon dioxide they inhale during breathing.

For our bodies, C02 is waste. Plants, on the other hand, depend upon it for food. Carbon dioxide dominated Earth’s early atmosphere, while oxygen barely existed. As plants began emerging — and respirating oxygen after they consumed C02 — the atmosphere eventually changed enough to support oxygen-breathing creatures.

A Trio of Big Carbon Capturing Buckets

We understand that for life on earth to survive, if not thrive, humans cannot continue pumping C02 into the atmosphere at current volumes. We also know that humanity’s C02 spigots are not even close to being shut off. 

So in addition to implementing plans to reduce C02 emissions, we need to find novel ways of trapping C02 before it is released into the atmosphere. We also must turn to strategies and technologies that capture ambient C02.

All approaches towards carbon capture today revolve around three broad categories: biological, geological and technological. Too bad there isn’t a “magical” category.

Biological Carbon Capture

The ocean absorbs carbon dioxide through photosynthesis, thanks largely to phytoplankton. Terrestrial plants absorb carbon through photosynthesis, and store it in soil. Forests, grasslands and rangelands are responsible for the capture of about 25 percent of global carbon emissions. Oceans capture another 25 percent.

Geological Carbon Capture

Biological carbon capture hinges on natural processes, which we can advance through technology and smart activity. Geological carbon sequestration, on the other hand, is the application of tech and tactics to at least mitigate the broadcasting of carbon that results from industrial activities, such as steel and cement production, natural gas processing and the running of power plants. Our electricity needs, which largely revolve around fossil fuels, account for 40 percent of C02 emissions worldwide. Geological carbon-capture technologies seize carbon before it is released and then store it in different ways, often by injecting it into rocks for storage.

Technological Carbon Capture

This sphere of activity requires heavy investments and loads of R&D. The goal: to develop technologies that remove carbon from the atmosphere and store it. Direct Air Capture (DAC) represents an interesting field of research, in which facilities are built specifically to capture carbon and store it. It is expensive. Another exciting zone of research centers on engineering molecules that will essentially hunt down and capture carbon dioxide.

Biological carbon-capture nurtures wild diversity of innovation

The geological and technological approaches to carbon capture are fascinating and promising. They remain nascent, however. In this guide, we focus largely on the biological solutions. Industries and companies around the world are investing in biological answers to carbon-storing questions

One of the more prominent efforts centers on what in fact is an ancient practice: regenerative agriculture.

Farming carbon with regenerative agriculture

Outside of farming circles, few people encountered the term regenerative agriculture until somewhere in the mid-2010s. Now, it’s fairly well known, in part due to things like the movie “Kiss the Ground,” narrated by Woody Harrelson. 

Conventional agriculture is a leading source of greenhouse gas emissions in the United States, responsible for 10 percent of emissions. It relies heavily on fertilizer, pesticides and herbicides, tillage, mono-cropping, and enormous machines.

Regenerative agriculture rejects much of what conventional agriculture embraces. From the beginning — the term was coined in the 1990s by Robert Rodale, the son of the founder of the organic agriculture movement J. I. Rodale — regenerative agriculture championed soil vitality as the most important part of agriculture. But as the climate crisis ripened and science began offering fresh options for wrestling with the unfolding horror, people began to find solutions in soil health.

In short, some of the practices surrounding regenerative agriculture may help retain carbon in the soil, rather than releasing it as happens in conventional agriculture. Building organic matter into the soil is key.

Soil rules where regen reigns

Regenerative agriculture shrinks from disturbing the soil through tilling and other practices. It trumpets the use of cover crops, which among other things regenerate microorganisms in the soil while simultaneously capturing carbon. It turns to a diversity of plant and animal species to improve ecosystems, toils to keep living roots in the soil, and integrates livestock into farming operations.

All of these practices could help turn farmland into carbon sinks — vast carbon storage basins. However, science into clear links between regenerative agriculture and carbon capture is not yet a slam dunk. Critics may support regenerative agriculture with gusto for many reasons, including overall soil health and ecological strength through diversity. But at the same time, some regenerative champions urge the movement to step away from its advocacy for regenerative agriculture as a route towards carbon capture.

A Tidy Plot of Key Regen Players

  • Regeneration International, a nonprofit that highlights connections between healthy soil, regenerative agriculture and land use, food, health, healthy economies, and climate change. 
  • Savory Network, a global group of leaders advancing regenerative agriculture, reversing desertification and combating climate change. It has 30 hubs around the world, which helps train people in regenerative agricultural practices in their unique contexts.

Waves of innovation sinking carbon in watery depths

As biological carbon capture largely revolves around plants, we tend to fix our focus upon the land. That’s where we find dense deciduous forests, corn fields and alpine meadows. But 71 percent of Earth’s surface is covered with ocean water, and plants that most of us rarely see fill the seas.

Ocean plants capture carbon. Encouraging their development through aquaculture is much less energy (and thus, carbon) intensive than terrestrial agriculture, as seaweed does not require fresh water or fertilizers, and it grows rapidly — as much as two feet a day. In addition, seaweed farms don’t compete with land agriculture or residential or commercial development. Nobody is planting corn in the Ionian Sea, or erecting townhouse developments in the Bering Strait.

One of they keys to making seaweed aquaculture especially meaningful for climate is for it to be either sunk or used after it reaches maturity. If it rots in the ocean, it releases C02.

The seaweed solution

Companies around the world are figuring out ways to grow seaweed and then sink it, where it will remain, becoming another layer of the sea floor. One company, Running Tide Technologies in Maine, aims to grow kelp micro-farms hundreds of miles offshore, over especially deep oceans. As the kelp inhales and absorbs carbon through photosynthesis, the beds expand. 

While it grows, buoys keep the kelp aloft, to ensure that the plants soak up as much carbon as possible before floating away and landing on a beach or just rotting. In just a bit more than six months the kelp blades become heavy enough to break free from the buoys and sink to the sea floor.

The project begins this year, with a pilot run of 1,600 buoys. Eventually, leaders in this field envision millions of small kelp farms capturing billions of tons of carbon from the atmosphere and locking it up at the bottom of oceans.

Eat your seaweed. Wear your kelp. 

Harvesting seaweed, rather than letting it rot, also captures the carbon. As researchers and companies invest increasingly more in seaweed product development, they are finding applications in food, of course, as well as cosmetics, hair care, supplements and other industries.

Examples of seaweed foods are myriad. Just last week, for example, the Irish company Plantruption developed the country’s first plant-based seafood product, called the Sea Weed Burger. 

Some of the leading companies involved in the seaweed protein market are:

  • Maine Coast Sea Vegetables: Familar Consumer Packaged Goods company offering range of seaweed products.
  • Acadian Seaplants: Canadian company investing heavily in science and R&D into seaweed commercialization.
  • ALGAIA: French seaweed company producing myriad different products.
  • Cargill: Large multinational food and agriculture conglomerate with sustainable seafood arm.

Packaging made from seaweed rather than plastic? Absolutely. Consider Notpla, a London company making packaging for things like ketchup packets, sauces and beverages out of seaweed and other plants. Evo & Co., in Jakarta, offers a broad set of seaweed-based plastic alternatives.

Another area of seaweed innovation: textiles. The New York company AlgiKnit in March announced a fundraise of $2.1 million to transform kelp into bio-yarns. If fashion finds cost-effective and practical ways to incorporate algae textiles into production, that should lead to fast expansion of the seaweed industry.

Seaweed flattens bovine flatulence

On a different but related front, researchers are exploring ways to use seaweed in animal feed, as a way to alleviate methane emissions. Cow farts and belches introduce enormous amounts of methane into the atmosphere. The gas is much more effective at trapping Earth’s heat than carbon dioxide. The company FutureFeed is creating algae-based additives to animal feed that will mitigate those deadly farts and burps. A recent double-blind study demonstrated that using the additive, derived from a species of red algae called asparagopsis, is effective.

Note of Caution

To make this happen, humans will have to create vast seaweed farms. We do not know what environmental impacts large seaweed farms will have on ocean ecosystems. For example, thick mats of seaweed would diminish sunlight spreading down through the ocean, which would impact photosynthesis processes. It could interfere with marine ecosystems in ways we do not yet understand.

Trees to carbon: you’re yummy

Forest ecosystems trap carbon in the trees as well as the soil. Within forests, scientists estimate that plants trap 31 percent of the carbon, and that forest soil contains 69 percent. In all, forests every year withdraw from the atmosphere about one-third of all human-caused C02.

They are serious carbon sinks. One mature tree absorbs 48 pounds of carbon dioxide a year. An acre forest can absorb twice the C02 emitted by an average vehicle over the course of a year.

Relying on forests for help with trapping carbon revolves around two tactics: protecting existing forests, and reforestation.

First, save the forests

All trees absorb carbon. But old trees do it with the most oomph. Trees with diameters so large that they represent just 1 percent of trees on earth hold half of the world’s carbon stores in forests, according to a 2018 study. When these forests are felled, the trees processed into tables and lumber and decks, we lose enormous carbon sinks. Forests populated with young trees absorb C02, but not at the rate of mature trees.

Ending deforestation and just letting old trees continue to grow, according to researchers, would permit forests worldwide to take up twice as much carbon than they are absorbing now. Constant deforestation hobbles forests’ role in cooling the planet. 

Efforts to simply protect forests from feller bunchers — gigantic logging machines that cut their way through forests like samurai at a Mongol party — are gaining momentum. A pair of researchers at Oregon State University and Tufts University recently suggested in a paper that countries begin looking at the U.S. Strategic Petroleum Reserve, of all things, as a model for forest preservation. 

A key quote from the paper: “We propose creating strategic forest carbon reserves to store carbon as a way of stabilizing the climate, much as the Strategic Petroleum Reserve helps to stabilize oil markets.”

Important forest-preserving organizations include:

Fostering a world of Joanie and Jiang Appleseeds

Preserving forests doesn’t get much press. Reforestation — planting trees — gets rock start treatment. As trees absorb atmospheric C02, the more trees on Earth, the more captured carbon.

But planting trees in volume and mass that will make a difference won’t come easy. An important study published in Science found Earth ecosystems could support another 2.2 billion acres of forests, which is 25 percent more forest than blankets Earth today. Planting a half trillion trees could capture 205 gigatons of carbon and reduce atmospheric carbon by 25 percent.

A world spangled with 25 percent more forests would eliminate 20 years of human-produced carbon emissions. This amounts to half of all carbon humans have broadcasted into the atmosphere since 1960.

The idea comes with myriad cautions. For one, 2.2 billion acres is about the size of the United States and Canada combined. If humans every year plant between about 25 and 50 trees per acre on two million acres, it would take between 1,000 and 2,000 years to achieve a vigorous carbon-trapping tree canopy. In addition, for each acre planted it will take about 100 years for it to reach maturity, which is when the forest’s carbon-trapping powers are at their height.

Large organizations involved with reforestation efforts include:

Our future hinges on a single gas

This exploration is not close to comprehensive. The volume of R&D, commercial innovation, activism and nonprofit leadership surrounding the places where carbon and climate intersect is far in excess of the content of this précis. 

A different kind of charcoal

One approach towards carbon capture that has gained some notice is biochar, which involves leveraging a process called pyrolysis to make a charcoal-like substance from organic forestry and agricultural waste.

Where traditional charcoal production releases carbon into the atmosphere, pyrolysis involves the burning of biomass in a nearly oxygen-free container. The result is essentially charcoal, with its carbon largely intact. Biochar can store carbon for thousands of years. One of the benefits of pyrolysis is the heat created during pyrolysis can be leveraged and used as a source of clean energy.

Cementing carbon storage in place

Carbon-storing cement, too, offers promise. Cement is the key ingredient in concrete. Creating cement for this ubiquitous building block releases so much C02 that if cement production were a country, only China and the United States would emit more C02.

Myriad companies are researching how to create cement without releasing so much carbon dioxide. One of them, CarbonCure Technologies, recently received huge investments from a consortium of companies, including Amazon and Microsoft, to roar ahead with R&D.

Carbon-infected cement produces stronger, more durable concrete; the C02 chemically transforms into limestone once injected. When CarbonCure began, the commercial angle was clear: the company produced better concrete by importing C02 from places like seltzer water facilities and injected it into its cement.

While that process does not reduce C02 emissions from cement manufacturing, it does offer enormous storage areas for C02 generated from elsewhere, such as oil and coal energy.

However, CarbonCure’s parade of large investments is propelling it towards technologies that would capture the C02 involved in cement manufacturing itself, and then inject it back into the cement. The system would be closed-loop, and if it works at scale could effectively reduce C02 emissions associated with cement production.

Storing energy industry’s carbon

Carbon capture technologies designed for fossil fuel companies and manufacturing behemoths like cement production are not embraced with keen enthusiasm across the spectrum of environmentalists. They warn that the enormously expensive gambits may never work, and will give some of the world’s worst carbon emitters cover while they continue to broadcast C02 and other greenhouse gases into the atmosphere.

The International Energy Agency in September of 2020, however, said the technologies are vital. Hitting climate targets worldwide without capturing and storing industrial emissions would be “virtually impossible,” the IEA said.

Carbon Capture & You

We have explored seaweed farming, interrogated regenerative agriculture, examined saving forests and considered efforts to mitigate carbon emissions among extraction industries.

Are there steps we can take in our homes and lives to reduce our carbon footprint? Can we capture carbon?

Yes. Individually, our efforts won’t make a difference. Collectively, they could help us save life on earth.

You might assess your own carbon footprint, through tools like Carbon Footprint and Terrapass. Googling reveals many calculators, including apps.

You can buy carbon offsets, too; buying offsets has become an industry unto itself, and is somewhat controversial. Critics charge that carbon offsets give people easy ways to ignore emissions while claiming sustainability responsibility.

We feel carbon offsets are wise investments in addition to reducing emissions. Terrapass, which offers a carbon calculator, sells offsets. So does Wren, Cloverly, and many more companies.

A smattering of ways to minimize your footprint

  • Drive eletric vehicles, turn more frequently to public transportation, drive less and bike or walk more

We love carbon. We need it. Among many other things, Earth without carbon would be awfully cold; its heat-trapping properties are essential for Earth’s life-sustaining temperatures. Too much of it, however, is too much of a good thing.

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