Can vacuuming carbon dioxide from the air reverse climate change? -Bulletin of Atomic Scientists

2021-11-24 04:58:29 By : Mr. Steven Pan

Illustration by Keith Negley/Mother Jones

Editor's note: This story was originally published by Mother Jones. It appears here as part of the climate service desk collaboration.

In British Columbia, there is a small valley where the Squamish River winds through the cliffs of Maramute, which is a popular hiking spot. Like most parts of British Columbia, the hills are densely covered with fir trees in all directions. Located in that valley is a novel industrial factory designed to replicate the role of millions of trees: to absorb carbon dioxide from the air.

The plant was built by Carbon Engineering, a pioneer in direct air capture (DAC) technology. In a long, low building, a huge ceiling fan draws air into the room, where it reacts with a liquid chemical to capture carbon dioxide molecules. This "adsorbent" flows into a nearby machine that converts the gas and then stores it in a pressurized tank. The goal is to help eliminate the most common culprit of climate change in the atmosphere. The Squamish plant will process up to 1,000 metric tons of carbon dioxide each year. This is insignificant compared to the Earth’s annual emissions, which were estimated at 33 billion metric tons last year, but the plant is only a pilot facility.

If the process can be scaled up on a large scale, what will happen to all the captured carbon dioxide? CEO Steve Oldham explained that there are several possibilities. For example, you can sell part of it to companies such as soda manufacturers or concrete manufacturers. You can also convert it into liquid fuel and burn it in cars, trucks, airplanes, and power plants. This will release more carbon dioxide, but in Oldham's vision, it involves a huge network of company machines, and you only need to run the pollution directly throughout the process. He said that you can do this over and over again to allow a society to burn fossil fuels forever without exacerbating global warming. Call it catch and release. Oldham believes that we should all join this carbon recycling model: "We can't wait. We must continue to decarbonize now."

Of course, governments around the world can do much more than capture and release. They can use direct air capture to capture excess atmospheric carbon and bury it deep in the earth, thus reversing the trend of the industrial revolution and thus completely reversing climate change. It will not be cheap to eliminate the billions of tons of so-called legacy carbon we have emitted in the past 150 years. At current prices, countries will have to pay a total of approximately US$5 trillion each year for the rest of this century. But a terrible August report from the United Nations Intergovernmental Panel on Climate Change (IPCC) warned that our climate conditions may decline so rapidly that we have no choice. Oldham believes that policymakers will most likely decide that it is worthwhile to eliminate all the remaining carbon. "I personally like the analogy of water treatment," he said. "When cholera and typhoid fever caused water problems, governments around the world built water treatment infrastructure. This is part of what they provide to citizens. Today we have air problems, so we need an air treatment infrastructure."

Use carbon dioxide inhalation machine to solve climate change? At first glance, this sounds like something from Neil Stephenson's science fiction novel—or a particularly crazy Silicon Valley TED talk. In fact, DAC has been in the realm of mad scientists for many years. There are only a few startups in the world fiddling with prototypes, and few serious investors pay attention.

With the release of the earlier IPCC report, all this changed in 2018. The team warned that if we want the planet to warm by no more than 1.5 degrees Celsius—the Paris Agreement’s goal of mitigating climate change—we need to drastically cut carbon dioxide in the atmosphere. Afforestation will help. The switch to renewable energy is also crucial. However, in view of the slow embrace of wind and solar energy by mankind, the IPCC believes that we must start to extract carbon directly from the atmosphere before 2100. A lot of carbon. 10 billion metric tons per year, equivalent to nearly one-third of our current carbon dioxide production.

Direct air capture and other capture and storage programs—from planting trees to figuring out how to get marine life to lock in excess carbon—suddenly become hot, and may even be vital to our long-term survival. Policy makers and companies, and even some environmentalists, have attracted people's attention. By the spring of 2021, more than 100 of the world’s largest companies, including Wall Street giants such as Pepsi, Alaska Airlines, Colgate Palmolive and Morgan Stanley, have pledged to achieve “net zero” emissions by 2040. Elon Musk’s fund $100 million will be set up for XPrize, a four-year competition aimed at stimulating the development of any technology (including DAC) that causes "negative emissions".

Public funds have also begun to flow in. The federal government and several states have passed tax credits for companies that can emit carbon from the atmosphere. The infrastructure bill approved by the Senate in August includes US$11.5 billion for various carbon capture tasks, including US$3.5 billion for the construction of four "regional direct air capture centers", which the federal government hopes will create a large clean energy work network. The Democratic Party’s $3.5 trillion budget blueprint includes $150 billion to compensate energy producers who switch to low-emission processes — Joe Manchin’s swing vote for this initiative — which may include direct air capture. Some Democrats are pushing for higher tax credits specifically for DAC. In June, the Department of Energy announced a grant of US$12 million to support "outstanding innovators" in the development of DAC technologies that can "help us avoid the worst effects of climate change." Even a few technology companies such as Stripe and Shopify have invested millions of dollars in budgets to purchase carbon dioxide that can be stored in any reasonable way. "You have gained such a huge momentum," said Erin Burns, executive director of Carbon180, a think tank.

In response, the pioneers of DAC are happily driving out of the new factory. Climeworks, based in Switzerland, is considering building a facility in the Middle East. The Global Thermostat in New York is preparing to build its first large-scale installation in Chile next year. Oxy Low Carbon Ventures (a division of the oil giant Occidental) will use Carbon Engineering's technology to build a Texas plant that will eventually remove up to 1 million metric tons of atmospheric carbon dioxide per year, 1,000 times that of the Squamish plant.

This sounds like a smart idea, but when you look closely at the world these companies envision, it becomes more complicated. According to entrepreneurs, the only viable way to save the planet is to involve fossil fuel companies. This is partly because Big Oil has the infrastructure and expertise to build such facilities on a large scale, and pipe the captured carbon dioxide to a place where it can be permanently isolated. But this is also because, in the eyes of the inventor of the DAC, the internal combustion engine will accompany us for some time. They envisioned mainly using DAC for capture and release in the next few decades: to collect carbon dioxide from the air, convert it into synthetic fuels, burn these fuels, and recapture the carbon dioxide. We will not start to remove legacy carbon before 2060 or 2070, because only then will DAC be made cheap enough through small improvements that companies and countries (at today’s tax rates anyway) will be willing to pay for it .

The inventor insists that in the long run, their technology can save us. At the same time, they are seeking help from the government and their partners in companies such as Exxon Mobil, Shell and Occidental.

2. Scientists who see our plight

The concept of direct carbon removal appeared in the late 1990s, when a few scientists envisioned a frustrating reality: Although people are increasingly aware that carbon dioxide produced by human activities is warming the earth and may have catastrophic consequences, Humans seem to be in no hurry to stop burning fossil fuels.

One of the scientists is Klaus Lackner, a moderate-speaking theoretical physicist who is increasingly interested in climate engineering. We met in his laboratory at Arizona State University, where his graduate students were repairing a small wind tunnel and blowing air on Lackner’s carbon dioxide absorbing materials in an attempt to improve their performance. He told me that his team is still in the early stages of experimentation; the researchers are not entirely convinced that DAC will be feasible on a large scale. "I promise nothing," he said. "What I really assure you is that if we can't try to make direct air capture work, life will be much harder."

Lackner is a tall German immigrant. As early as the 1990s, he predicted that fossil fuel emissions would increase dramatically, because the fast-growing China and the global South would need the same cheap growth opportunities as other countries. At that time, solar and wind energy could not compete with fossil fuels in cost.

Since emissions are about to explode, Lackner believes that the only way to solve the problem is to absorb them again. In 1999, he co-authored a paper on the "Coal Utilization and Fuel System" conference, calling for the development of DAC technology. He recalled: "What I worry about is that we will have many excuses why we can have more carbon dioxide in the atmosphere—unless we have a cheap solution to restore it." He envisioned a certification system: if one If a company wants to emit a ton of carbon dioxide, it must prove that it has emitted a ton of carbon dioxide. "If you want to extract fossil carbon, please be my guest," Lackner told me. "But you must prove to me that the same amount of carbon has been stored."

Over the next few years, he traveled the world, talked about his ideas, and discovered that two other scientists had similar ideas. One is Peter Eisenberg, an old friend and physicist at the Earth Institute of Columbia University. As early as the 1970s and 1980s, as the head of ExxonMobil's R&D laboratory, Eisenberg tried the concept of collecting carbon dioxide from the air—he called it "artificial photosynthesis." Another like-minded person is Harvard physicist David Keith, who has been studying solar geoengineering, which is a method of curbing warming by limiting the amount of sunlight that hits the earth. These three people will eventually set up a company to develop DAC.

Keith was the first to pull it down. In 2004, he established a research group at the University of Calgary and devoted himself to the field of chemistry. Capturing carbon dioxide is not a new art. Designers of submarines and spacecraft have been doing this for decades to keep the air on board breathable. Fossil fuel companies have also designed "scrubber" systems to capture carbon dioxide in the chimney, although these systems have never been deployed on a large scale-probably because the company considers them too expensive. Adsorbent chemicals that can sequester carbon dioxide at different temperatures are available. The difficulty is that carbon dioxide is very thin in everyday air-about 0.04%. Any DAC system must move a large amount of air to capture a relatively small amount of carbon. Nonetheless, this seems feasible: “The more we research from an academic perspective, the more we find that there are no obstacles to scientific display here,” said Jeff Holm, a member of Keith’s original research team and current director of carbon engineering business development. Geoff Holmes said. The big challenge in engineering and design is: Do you manufacture millions of small devices and distribute them all over the world, or build a small number of large factories? Can you use renewable energy or fossil fuels in small enough quantities to power these factories so that they absorb far more carbon than they release?

Keith's team chose to scale up and designed a plant that can capture 1 million tons or more of carbon dioxide each year-roughly equivalent to the emissions of 217,000 cars. Another cost-saving decision his team made at the beginning was that they would only use existing off-the-shelf parts and technology. For example, they will use the same type of cooling towers deployed in factories around the world to expose the adsorbent to the outside air. In order to purify the captured carbon dioxide, they reused technologies from the wastewater treatment and mining sectors. The last step of the carbon engineering process involved temperatures of up to 900 degrees Celsius-energy intensive-so they designed a plant that could run on renewable energy or natural gas. If it is a gas, the resulting emissions may be captured and transported through the process in which they are activated.

Keith and his partners officially launched the carbon project in 2009. They received $3.5 million in seed funding from Bill Gates and Murray Edwards. Murray Edwards is a Canadian billionaire. The money is to extract dirty crude oil from the oil sands of Alberta. Later, another 3 million U.S. dollars came from government sources. By 2015, the team was encouraged by laboratory results and began to build a prototype of Squamish.

Holmes told me that mastering direct air capture is a task that requires thousands of fine adjustments. He said, "There is not a light bulb." "No one ran out of the lab and said,'Yes, I solved it!'" In his opinion, the learning curve of DAC is similar to the learning curve of solar panels, after decades of gradual improvement-maybe every year 2% output-now the world's lowest energy source for construction and installation.

Other teams have taken a slightly different route. Klaus Lackner wanted a system that was small enough to fit anywhere and required very little electricity to run. He set out to create a "mechanical tree" covered with rows of dry adsorbents. Unlike competitors' equipment, his trees don't need fans to blow through the adsorbent; they rely on wind. This means that they only need electricity a few times a day, when the "leaf" collapses into a jar where the steam is used to extract carbon dioxide. Each tree only removes a small amount of carbon, but because these devices consume very little power, Lackner envisions installing them in the number of forests—millions of them. Since carbon dioxide is evenly distributed in the lower atmosphere, you can place them anywhere on the earth with power and sufficient infrastructure to bury, transport or otherwise use the extracted carbon.

Eisenberger co-founded Global Thermostat with economist Graciela Chichilnisky from Columbia University, which helped design the carbon trading mechanism in the Kyoto Protocol. Like Lackner, the two opted for a smaller, lower-power design. The fan blows air through the ceramic cubes coated with adsorbent, hitting it with steam several times per hour to remove the bound carbon dioxide. They designed the system to match the industrial process-you can install one next to the air conditioning unit in the factory, and its waste heat can be used to power the machine. (The early factories built by Climeworks had roughly the same technology, powered by geothermal energy.)

In May of this year, I visited SRI International, a research laboratory in Menlo Park, California, and witnessed the prototype of the Global Thermostat. The machine is about 60 feet tall, with a layer of PVC pipe winding around its wide metal base. At the top, I can see a row of fans blowing past a large metal accordion with adsorbent-coated ceramics. I watched the accordion fall on the base, where it extracts carbon dioxide.

With the development of cutting-edge technology, this machine is anticlimactic. It will be integrated with any industrial machinery you might find on the job site. This is the point, Chichilnisky told me on the phone last winter. Like Lackner, she and Eisenberg envisioned installing millions of devices in cities and industrial parks around the world to use waste heat to reduce carbon pollution. "This is cultivating the sky," she said.

3. The climate modeler in panic

If the DAC really takes off, you can thank the climate modelers for their psychology.

By the early 2000s, scientists had predicted a bleak future. They considered countless factors that affect warming, including the volume and effectiveness of endothermic gases, the rate at which these gases are prevalent, and the earth's natural mechanisms for capturing and storing carbon, such as trees. Obviously, countries around the world have made little progress in getting rid of fossil fuels. So climatologists are starting to wonder: what if you include the "net negative" technology that artificially removes carbon dioxide from the air?

Some scientists speculate that people might use a new process they call bioenergy with carbon capture and storage (or storage) to do this. You can plant an endless loop of fast-growing trees or crops, burn biomass to generate electricity, capture the carbon dioxide produced from the chimneys of plants, and inject it deep underground (ideally, in porous rocks such as basalt, which contains A large number of tiny carbon dioxide molecules can fill the gap). In theory, if you replace thousands of fossil fuel plants with BECCS plants, you can generate a lot of electricity and generate a net negative value because your biomass has already absorbed a lot of carbon from the air through photosynthesis-now carbon is bury. Sure enough, when scientists incorporated BECCS into their model, it helped to balance the books. They can make scenes of a large number of power plants, which will start to allow humans to come back from the climate abyss.

After the Paris Agreement was reached in 2015, the hustle and bustle of BECCS reached its peak, when 191 countries signed an ambitious new goal: they will take collective action to limit the temperature rise to “far below” 2 degrees Celsius by 2100, and work hard. Keep it at 1.5 degrees Celsius. The Intergovernmental Panel on Climate Change was asked to create four ways to keep warming within the promised range. The most optimistic one assumes that the country will take immediate action to transform its energy flow, introduce renewable energy, and realize the electrification of transportation. No carbon removal technology is required.

The other three approaches take a darker and more realistic view of human nature. These assessments assume that countries will slowly accept renewable energy, and we will "excessive" within a few decades. We will emit a lot of carbon dioxide, and if severe measures are not taken, the temperature will far exceed 1.5 degrees-causing devastating effects, including wilder and sharper weather, and deaths due to severe droughts, fires, floods, and famines. Billion people. In order to improve overshoot, we must increase carbon sequestration efforts. This will require a lot of tree planting-as opposed to deforestation-and we must take seriously forcing coal and natural gas power plants to capture emissions at the source.

But this is not enough. IPCC stated that we also need "net negative" technology-including BECCS factories. The three alternative approaches of the expert group assume that we will build a large number of such devices and increase the speed until 2050, we will extract up to 1 billion tons of carbon dioxide from the air each year, which will double by 2100. Only in this way can we achieve a temperature rise of less than 1.5 degrees by 2100.

There is only one problem: energy experts agree that large-scale BECCS is an illusion. This idea looks neat on paper, but launching it as envisioned by the IPCC will require a lot of real estate. The National Academy of Sciences calculated in a study that you must invest as much as 40% of the global farmland to grow trees and plants for burning. Another paper estimated that the plan would require a territory equivalent to India. "We have no land," Felix Creutzig of the Mercator Global Commons and Climate Change Institute told me candidly. His team has studied all the ideas that humans have put forward to capture carbon, including BECCS, afforestation, DAC, and various methods of absorbing carbon dioxide into the ocean.

Afforestation and reforestation encountered the same problems as BECCS. Oxfam reported in August that planting enough trees to reach net zero by 2050 will require 4 billion acres, equivalent to more than 80% of all existing farmland on the planet. As for the idea of ​​closing the gap with BECCS, “if you only include biodiversity for one second, it’s basically impossible,” Creutzig said. This is why there are almost no BECCS plants in operation today.

The fact is that some climatologists who have used BECCS in their models for many years know that it will never be feasible, long-term climate modeler Wolfgang Knorr told me. He said: "This is an avoidance strategy," a coping mechanism for frightened scientists. "You just don't want to look directly at the truth-we have waited too long" to stop burning fossil fuels.

In contrast, DAC is not a fantasy. This technology, which is already in development, does not require as much land as BECCS. Even tens of millions of machines occupy much less space than biomass crops. In terms of engineering, DAC can be extended. And as it develops, it should become cheaper and more efficient. Most technologies follow a learning curve similar to Moore's Law in the computer industry: the more things you make, the more efficiently you can do it, and the cheaper the technology becomes. (Usually, every time you double the number of goods on the market, the price drops by 10% to 20%.) This is how the PC went from thousands of dollars in the 1970s to 25 dollars for today's Raspberry Pi computers. Biological solutions are difficult to scale; there are not so many machines.

In any case, the 2018 IPCC report made policy makers and investors suddenly pay more attention to DAC. The team’s new report is even more frightening, and it reiterates its view: Large-scale carbon absorption is almost certainly necessary. Entrepreneurs of DAC cannot demand better timing. Most people have proven that they can capture carbon dioxide from the air. The big question that remains is: Who is willing to pay them enough money to do it on a large scale?

4. Who wants to buy a ton of carbon dioxide?

This is a tricky question. Currently, companies like Climeworks or Carbon Engineering charge approximately US$500 per ton of carbon dioxide captured. To achieve the IPCC's goal of storing 1 billion tons per year by the middle of this century, it will cost 5 trillion US dollars a year. Most observers believe that the price must be reduced to $100-ideally much lower-to make the DAC feasible.

The inventor said that the only way to reduce these costs is to subsidize their operations. If they can launch thousands of DAC machines in the next few decades, the price will definitely plummet. But someone is willing to pay $500 per ton to start work. In 2019, Stripe, which makes payment processing software, announced the establishment of a small climate fund to buy atmospheric carbon from anyone who permanently stores atmospheric carbon at any price. So far, it has spent US$8 million, including purchases from Climeworks and Charm Industrial, which liquefy the plant waste from the farm into oil and then bury it. Stripe climate expert Nan Ransohoff said that Stripe's cost is much higher than $500 per ton, but "we are looking for projects that may drop below $100 by 2040." Specifically, projects that don't require much land.

In fact, every participant in the emerging carbon removal industry has provided a reason for the government to invest in starting pumps, just as the public has supported the development of wind and solar energy in the past few decades. President Obama’s 2009 stimulus bill included a small amount of money for research on climate solutions. The previous year, Congress approved generous subsidies for any company that captures and stores carbon dioxide per ton under Article 45Q of the Tax Code-the law was amended in 2018 to include DAC in the name. (The Biden administration is seeking to expand the 45Q program.) At the same time, California and Washington have created tax credits for companies that store carbon dioxide.

These subsidies make the DAC project profitable if it is barely profitable. The most ambitious plant to date is the Texas plant built by Oxy Low Carbon Ventures in cooperation with Carbon Engineering, which can remove up to 1 million tons of carbon dioxide each year. These terms are confidential, but Oldham, CEO of Carbon Engineering, emphasized the role of the government: For each ton captured, 45Q credits pay up to $35, while California offsets are $200. (California credits apply to carbon emissions in Texas or any state—location doesn’t matter.) “You can make economics work,” Holmes told me.

But the details of the project quickly turned to areas that disturbed environmentalists. This is because business partners intend to use a method called "enhanced oil recovery" to sequester carbon. In other words, they will inject carbon dioxide into nearly depleted oil and gas wells to help extract what is left. For decades, energy companies have been using this technology to maximize profits. For example, historically, Occidental Petroleum has had to pay about $25 per ton for the carbon dioxide it uses, so capturing the carbon dioxide makes its operations more profitable.

This makes business sense. But to many environmentalists, this seems crazy. "If you ask people,'Hey, do you think it is a good idea to absorb carbon from the air?' They will say,'Yes, this is a good idea!'" said John Noel, a senior climate activist at Greenpeace . "Then, if you say to them,'Do you think you should push this carbon into the ground to push more gas and oil there?' They are like,'What? This sounds crazy!'"

Representatives of the federal and state governments are usually supported by fossil fuel interests, but don’t think this is crazy at all. Industry lobbyists worked closely with elected leaders to make sure firms using DAC for enhanced oil recovery would be eligible for sequestration credits. But the cooperation goes further. The inventors of DAC and its supporters clearly pointed out that expanding the scale requires them to work hand in hand with Big Oil. Most people would say that the only feasible way is to extend the era of internal combustion engines and fossil fuel power generation by several decades.

5. Synthetic fuel vision

It is worth explaining in detail the arguments of DAC visionaries, if only to grasp their worldview. If you want to remove 10 billion metric tons of carbon dioxide every year, they say that unless you lower the price, you can't do this with DAC. Improved oil recovery is a starter. This means that more fossil fuels are being mined and burned, but the net emissions are less than they would otherwise be. More importantly, supporters point out that enhanced oil recovery provides a direct market for the captured carbon. Oil companies need large amounts of carbon dioxide to increase oil recovery. The only other markets that exist, such as the manufacture of carbonated beverages and dry ice, are relatively small. Potential larger markets—such as mixing carbon dioxide into concrete or using it to make carbon fiber materials for cars, clothes, and even buildings—are still in their infancy.

The next stage of the DAC booster debate is even bolder: their technology should first be used to produce synthetic fuels for internal combustion engines. They believe that this will decarbonize the world faster than trying to switch to solar and wind energy cars and power plants. On the surface, this seems to be a strange, circuitous detour. Solar and wind energy have become extremely cheap energy sources with very little emissions. Most environmentalists — and the Biden administration, which recently called for large-scale solar expansion — think we should aggressively scale up immediately. But wind energy and solar energy have a major storage and distribution problem. Arizona has plenty of sunshine and Texas has plenty of wind, but so far, we have no effective way to send electricity to Boston or North Dakota. Storing electricity at night or during periods of no wind requires batteries, which requires resource-intensive mining.

In this regard, liquid fuels still have advantages. Compared with today's batteries, they can hold more energy per pound. Oil and gas companies also have experience in storing and transporting them across the country—and the existing infrastructure that can do this. Proponents of DAC pointed out that liquid fuels still need to power large vehicles, especially long-haul aircraft, because today's batteries are too heavy-many environmentalists I talk to admit this. "I think it will take a while for us to remove the entire internal combustion engine type mechanism from the earth," Carbon Engineering's Oldham told me. "There are many of them. In many different places." Even vehicles that can be electrified today, such as light cars, are not electrified fast enough.

Therefore, as DAC proponents say, our best option is to work within the existing oil and gas infrastructure. You will use DAC to absorb large amounts of carbon dioxide and use solar or wind energy to convert it into carbon monoxide and oxygen. In addition, using electrolysis, you can split water into hydrogen and oxygen. The fuel produced by combining hydrogen and carbon monoxide under appropriate conditions can power ships, trucks and airplanes with only a slight modification of the engine. Burning synthetic fuels emits carbon dioxide, but if you take the capture and release route, in Oldham's words, you create a "closed loop."

Lackner said that another way of thinking is that you are making a liquid battery to hold wind and solar energy. You waste some energy in this process, but you have solved your storage and distribution problems. Energy companies in Texas can use solar DACs to produce synthetic fuel tanks and then ship them to Boston to generate electricity when the sun goes down.

According to this logic, the direct benefit is that you are decarbonizing internal combustion. Drivers will still use gasoline engines, but in theory, the climate impact will be neutral. For every exhaust pipe that emits carbon dioxide, a DAC device somewhere on the earth will absorb the same amount of carbon dioxide and put it back into use as fuel. "I can put it in the cheapest place, such as China or Australia," Lackner said.

"You make the oil company and all of its infrastructure part of the solution, not part of the problem," added Eisenberger, co-founder of Global Thermostat. "You relieved the tremendous pressure on capital investment needs."

Realizing the "net neutral" part of the vision will require large-scale expansion of solar and wind energy. Global Thermostat chose Chile as its first synthetic fuel power plant because the country is rich in wind resources. GT is building carbon capture devices, Siemens is building electrolysis components, and ExxonMobil will produce synthetic fuels.

If the use of liquid fuel is accepted as a prerequisite for batteries, the inventor pointed out that creating a huge synthetic fuel market will greatly accelerate the improvement of DAC technology and make it cheaper. Lackner predicts that successful scale-up will cost as low as US$50 per ton within a few decades-cheap enough for the government to solve the legacy carbon problem. But the reduction will not begin until around 2060, after we neutralize the transportation network.

If and when we manage to achieve it, removing large amounts of carbon will require large amounts of DAC machines. According to a recent study in Science magazine, to achieve the IPCC's 10 billion tons per year target by the middle of this century, you need 30,000 factories, the size of which is equivalent to the scale of the carbon engineering Texas factory. With smaller Climeworks or Global Thermostat devices, you need 30 million, and with Lackner’s trees, you may need more.

Building a carbon extractor of this scale sounds almost delusional. But Lackner countered that when you consider the efforts of other humans, this is not the case. After all, he pointed out, “We produce nearly 100 million cars and trucks every year.”

6. Dangers of business as usual

Many environmentalists believe that the DAC Visionary’s game plan is absurd, a complicated bank shooter that cannot work. June Sekera, a visiting scholar at the New School of Social Studies, analyzed 200 academic papers on DAC to determine its risks. He said the scale of this effort "will make dealing with the coronavirus look like a game of play." ". Sekera concluded from her analysis that extracting, transporting and burying so much captured carbon dioxide would lead to disaster.

Of course, one can juxtapose the DAC plant with the synthetic fuel plant, but Sekra said that permanently burying billions of tons of excess carbon would be a logistical nightmare. First, you need to transport carbon dioxide from the DAC unit to a location with the type of underground rock needed to isolate the gas. This will require a dedicated high-pressure pipeline network crisscrossed. (The existing oil and gas pipeline will not cut it.) It is estimated that by 2050, we will need at least 65,000 miles—12 times more than today. For this and other considerations, the authors of a 2020 study in the journal Nature Communications declared DAC a "energy and economically costly interference."

More importantly, a carbon dioxide pipeline leak can be fatal. Carbon dioxide is heavier than the nitrogen and oxygen that dominate the air we breathe. If the pipeline breaks, the concentrated carbon dioxide will initially be suspended near the ground, where it can make pets, livestock, and people sick and suffocated. (Recently pipelines in Louisiana and Mississippi ruptured, and carbon dioxide was used to improve oil recovery, sending dozens of people to hospitals.) If history can be used as a guide, then the new pipeline will pass through some of the poorest areas in the United States. Rohr Muffet said, CEO of the Center for International Environmental Law, who opposed DAC. "When you increase carbon capture or direct air capture in or around industrial facilities, the vast majority of these facilities are concentrated in communities of color," he added. "Not only in the United States, but also in all parts of the world."

Finally, we have the energy paradox. According to a 2019 study in the journal Nature, machines that need to absorb 10 billion tons of carbon dioxide each year will consume more than half of the world's current energy supply. Using DAC to build a closed loop of synthetic fuels will require more energy, as well as a huge expansion of solar and wind energy capacity.

So, environmentalists often wonder, why would we bother to spend all this clean energy on DAC? On the contrary, why not work hard to promote the electrification of our economy and get rid of as many fuel engines as possible as soon as possible? Lindsay Meiman, a communications expert at, an environmental group, said that the sooner we do this, the less DAC we need in the long run. "We have these solutions-we have," she said. "It's about political will, investment, and priorities." The government should prioritize investment in "free public transportation to create millions of jobs to dismantle these current fossil fuel projects."

"Once you start to calculate these numbers, you will realize that it makes more sense to simply eliminate most of the emissions," said David Morrow, research director of the Institute of Carbon Removal Law and Policy at American University.

Critics say that perhaps the biggest problem with the way DAC is launched and subsidized now is that it allows fossil fuel interests to operate as usual. In Muffint's view, the oil giants see cooperation with companies such as Global Thermostat and Carbon Engineering as a survival strategy. In the past few decades, polluters have claimed that they can capture carbon dioxide from chimneys, thereby enabling coal and gas-fired power generation to achieve zero emissions, but they have never done so. Now they claim that we can extract carbon from the sky. For fossil fuel companies, "Any technology that can say,'Hey, we don't have to stop emitting these things-we can find a way to make it disappear' is very desirable," Muffint said.

7. A case of gradual carbon absorption

Despite their deep skepticism, even many environmentalists who are ostracized by the fossil fuel industry have an annoying question in their minds: What if carbon sequestration is necessary? If humans cannot — or will not — act fast enough on renewable energy and discover that the IPCC is right later in this century: what do we just need to get rid of excess carbon? Noel of Greenpeace strongly opposes large oil and gas companies. "We need a political, financial, and cultural audience to isolate the fossil fuel industry from all corners of life," he almost yelled to me on the phone. "In policy circles, they should not be allowed to enter the negotiating table. They should not be allowed to advertise. They should not be invited to any serious meetings." He thinks they use DAC as a trick: "The technology has been Capture, manipulate, use, and throw into the public shutdown machine."

But still—still—Noël admits that government funding for scientists and engineers to study DAC technology might be a good idea. He wants us to have this option in our pockets, just in case. "I have a 9-month-old daughter, and our carbon dioxide content is 415 parts per million," he said. Considering that we have seen the serious effects of climate change, Noël is very worried about what it will look like in a few decades if we don't brake. As long as he is "completely decoupled from the fossil fuel industry", he can accept someone to do this work. Other environmentalists gave the same cautious approval. Morrow told me that carbon absorption should be our last resort, and we can only use it cautiously after we shift as much of the economy as possible to renewable energy: "The role DAC can play is important but limited. Where do we clean up? A good way to clean things up, or to reduce the carbon left over."

One can even make a clear progressive case for DAC. This is the view of Holly Jean Buck, assistant professor of environment and sustainable development at the University of Buffalo and author of "Ending Fossil Fuel." Buck points out that the United States is not only rich — partly because we have been free to emit carbon dioxide while enjoying cheap energy for decades — but we also have a lot of land that is geologically suitable for storage; more than most countries. For the sake of environmental justice, the United States can implement DAC domestically to help cope with the emissions of developing countries around the world: "We have given up some carbon, and other countries can continue to have more time to figure out what their transformation path looks like. ."

If properly managed, DAC may also become a good source of labor union-scale work in the United States. Erin Burns, the head of Carbon180, pointed out that the solar industry has suffered a political blow here, partly because we handed over most of the panel manufacturing to China, so solar energy has not yet created many manufacturing jobs. (However, installation work is booming.) This time, we can make policies to force domestic DAC companies to use locally produced steel, pay union wages, and seek meaningful input from affected communities to do better. Burns is from southern West Virginia, where the coal mining community does not get a lot of good jobs from renewable energy: "We want to learn from this experience and say,'Well, somehow expand direct air capture What is the scale of this? Is that just and fair?'"

DAC skeptics insist that control of development and promotion should be taken away from the big polluters. However, no one has really worked out a clear path to make DAC feasible without the fossil fuel sector. The government can fund researchers to research and store science and build prototypes, but it does not have the human or industrial resources to design and mass-produce DAC machines. Most large-scale projects purchased by the government are now built by contractors anyway, so at best, the construction of government-owned carbon dioxide pipelines and DAC machines can be outsourced to major industries including oil and gas.

Even so, even the public may have a surprisingly strong voice on how the private sector solves this problem. Since there is no free market for captured carbon dioxide, anyone who pursues DAC technology needs generous subsidies. This means that, as Buck pointed out, input and lobbying from environmental and public interest groups can shape the trajectory. For example, every skeptic I interviewed wants Congress to revise the 45Q credit line so that fossil fuel companies cannot charge for oil recovery using captured carbon dioxide. Senator Ron Wyden (D-Ore.) introduced a piece of legislation-the United States Clean Energy Act-to do just that. (Buck asserted that the federal government could even nationalize oil and gas companies and force them to introduce DACs. After all, these industrial giants helped create a socialization crisis, she said, so maybe the public should have it like the Fed in 2008 After the rescue plan, holding a large number of (if temporary) shares in several automakers is the same.)

Finally, the progressive argument insists that DAC is not our tool of choice. Before investing a lot of public funds to incentivize it, we should first invest our subsidies into renewable energy. As for carbon absorption, we hope to adopt low-tech, nature-based technologies as much as possible. To what extent can we promote reforestation? Ocean storage can be explored more actively-for example, treating beaches with chemicals to force sand to absorb carbon dioxide or grow plankton that metabolizes carbon dioxide. Although BECCS may be an idiot, the farm does generate large amounts of biological waste that can be used for storage—about 104 million tons per year.

But we may still need those DAC machines. When I first talked with Lackner, he thought that mankind has been away from the ideal time for oil and gas. "In 1980, we could have said,'Let's stop!' Instead, we procrastinated," he told me. If his technique is as he wishes, we will be lucky. When I visited his lab in the summer, there was the atmosphere of all the tech startups I visited: very excited, but not guaranteed. DAC is a classic industrial Wild West story-no one knows who will win or whether it is possible to win.

However, Lackner is hopeful with his dry and cold style. He took me to a gravel construction area outside, where his team will install the first prototype of his next generation carbon tree later this year. A cherry picker stood in the middle of the ground. Lackner's newest tree consists of a stack of 30-foot-tall adsorbent disks. He said that it may not look like much, but neither did the windmills of the 80s and 90s. Now let's see how powerful they are. "If we can extract wind energy from the air," he said, "we can extract carbon dioxide."

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Keywords: carbon dioxide emissions, carbon dioxide removal, carbon storage, climate change solutions, climate crisis, direct air capture theme: climate change

This is total nonsense. These delusions must be put into action, "whether environmentalists like it or not", which is despicable. It seems that the only people who really care about this are in the way, and whatever they say is important. Carbon storage/capture/anything is just another opportunity to bring a big payday to the well-funded fraudsters who are destroying the world. What we need is the ongoing major international conference that brings together all the trained scientists in the world whose education and work may in any way help develop mitigation strategies...Read more »

This announcement should not publish such articles. Neither should Mother Jones. Direct Air Capture is not just stupid, although it is stupid enough from an engineering and economic point of view. It is evil. This is the evil interference conceived by fossil fuel lobby groups (such as the so-called ecological modernists of the Breakthrough Institute). Tar sands billionaire N. Murray Edwards is one of David Keith's Carbon Engineering financiers, as is Bill Gates. Wind energy, solar energy and efficiency play a huge role, now, and can be increased several times to replace all coal, oil and natural gas...Read more »

Very interesting and informative article. Thank you. On the one hand, I have always believed that in addition to using wind, solar, water, reforestation, oceans and all other energy sources, we also need to remove carbon dioxide from the atmosphere. We have gone beyond the point of stopping emissions, because this seems to be impossible both politically and economically on a global scale. (One also needs to remember that the big oil companies "control" almost all local policy/politicians through their campaign contributions, so it is better to cooperate with them than to oppose them.) Therefore, I think besides...Read more "

This article is drippng poison. You John Werfel has no right to surrender. Working with the oil, gas, and coal industries in accordance with your suggestions is not spineless and unnecessary. Of course, we can stop coal mining and coal power. In several countries, it is happening now. There are no coal mines in Britain, France or Germany. The peak of coal has already occurred in the United States, and may also occur in the world. We can win, so why give up and hand the ridiculous vacuum cleaner to their grandchildren as their only legacy instead of taking climate action now. We cannot more »

Although I am also skeptical of DAC (for technical reasons), I think it is important to be accurate. Unfortunately, your comment on coal is not very accurate. Germany is still mining coal, and it is likely to continue mining until the late 2030s. The Washington Post has a good article on this: France did close coal mines (2004), But it is still being imported, mainly from South Africa, Australia and the United States. The UK is currently considering opening a new deep coal mine in West Cumbria, see I am not a fan. Said coal (of course more »

You should be a scientist. This means doubt. In order to filter out 400 carbon dioxide molecules, you must filter out 1,000,000 air molecules. Do you remember Gibbs' free energy equation? It still applies. Do you know how many narrow pass filters CO2 are in infrared? Even the IPCC recognizes that CO2 will return 3.75 watts/m^2 of long-wavelength infrared rays. This is 1 night light every four square meters. When the solar energy is 500-1300 watts/m^2, there is no measurable difference during the day.

this is very simple. Plant more trees and stop destroying the Amazon rainforest.

Well, I have no objection. The carbon tax/UBI system should help make DAC financially feasible, and then allow it to compete on cost through reduction or BECCS or other means. Maybe some research subsidies. But what shouldn't happen is to bet that some huge advances in DAC will save us. I don’t believe that a fractured reservoir will never leak. Substituting carbon dioxide for oil will still produce more carbon in the air. Not to mention dry ice and soda water, they will return to the atmosphere almost immediately. Active stone may work...DAC may become...Read more »

Clive Thompson is a contributing writer for The New York Times magazine and a columnist for Wired magazine...Read more

Richard CJ Somerville

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