Tree versus Tree
How much steel and copper is needed to grow a forest?
Last week in Gaia’s Way Out we looked at natural trees in comparison to artificial trees in their ability to pull carbon dioxide from the atmosphere and restore climate balance before we all go extinct. Advocates for artificial trees, known to climate wonks and tech industrialists as Direct Air Capture (DAC) or Direct Air Carbon Capture and Storage (DACCS), are keen to tell you one of their “trees” is 10,000 times more effective at vacuuming CO2 than a natural tree. Let’s examine that claim more closely.
One clue lies in the acronyms. DAC is simply a machine that separates carbon dioxide from ambient air, usually by a chemical reaction. DACCS adds an extension to the machine to keep the CO2 safely stored—think of the bag on a vacuum cleaner. To get DAC going, start-up projects have focused on air capture followed by mediated release. The example I gave last week was a CO2-infused vodka. Once it leaves the bottle it is headed back to the atmosphere. Indeed, beverage companies have been one of the early sponsors of DAC, because they need CO2 to carbonate your favorite beverage. Greenhouses also benefit from high CO2 concentrations, so flower-growing companies provide another value proposition partnership for DAC start-ups. So does “enhanced oil recovery” that pushes CO2 gas into tight rock formations to drive commercially valuable shale gas and methane to the surface.
I like to call this “catch and release.”
Long-term storage—centuries to millennia and beyond—is not as simple as catch and release. In Iceland, Climeworks accomplishes CCS by pumping captured CO2—after scrubbing it from the DAC device with chemical reagents—down deep shafts into volcanic rock where it “marries” recently formed lava basalts that are receptive to bonding with carbon. That traps the captured carbon in the rock, more or less permanently.
There are some receptive basaltic formations in North America, but they are few and far between. Drilling into them may mean sinking a borehole a mile deep and then using powerful pumps to take CO2 transported to the site by pipeline and forcing it down to the rock interface. Once that interface has been saturated with gas, the insertion point has to move up or down until the zone has been saturated, and then a new borehole is drilled. Typical CCS boreholes cost several million dollars.
The energy requirement in Iceland is met by cheap, abundant geothermal and hydropower. In North America, as in much of the rest of the world, power would need to come from some other source. If you don’t care to negate the whole purpose by burning fossil energy, the preference would be renewables like wind, solar and hydropower or the far more expensive, dangerous and toxic nuclear alternative.
Climeworks estimates their DACCS energy requirement is 7.2 GJ (or 2,000 kWh/tCO2). Carbon Engineering estimates energy requirements of around 8.8 GJ/tCO2 (or 2,400 kWh/tCO2).
A quick back-of-the-envelope calculation tells us 60% of world electricity production would be required to reduce CO2 levels—currently 200 ppm too high—by 1 ppm. That number is actually low because it does not account for ocean off-gassing that will quickly (within 30 years) replace any CO2 you pull from the atmosphere.
Using all of that renewable energy to do carbon capture while trying to use it to replace fossil energy, switch to electric cars, replace gas stoves with induction burners, and build bullet trains to replace air travel puts the whole renewables transition in jeopardy.
Doing DAC in Iceland where you have free energy, a high concentration of CO2 and basaltic geological repositories all in one place makes sense. Not so much in Montreal, Houston, or Sacramento. If throwing money would change that then perhaps there would be some rational justification for taxpayers spending $3.5 billion for four DAC hubs, $100 million for a commercial DAC prize, and $15 million for a pre-commercial DAC prize in the 2022 DoE authorization, or the $4.6 billion taxpayer funding going to support enabling infrastructure like CO2 pipelines and geologic sequestration.
However, power is not the only consideration. Increases in the producer price index in the past two years have raised the cost of:
Fabricated steel plate by 54%
Carbon steel piping by 106%
Electrical equipment by 25%
Fabricated structural steel by 70%
Copper wire and cable by 32%
Scarcity of resources is one reason that Small Modular Reactors that Bill Gates’ said would be available to Walmart shoppers by 2025 have gone up in price from $12 per MWe to $102 per MWh since 2016. These pre-positioned dirty bombs—whose warranties will expire long before the plutonium they generate—will not be coming soon to a Blue Light Special near you, even if you live in the remote Wyoming town Gates and Buffet bought for their experiment.
How much steel and copper is needed to grow a forest and sequester carbon? What rare and expensive resources are necessary to start a kelp plantation that will not just boost CO2 removal but also revive decimated fish stocks? As more forests reclaim lands they once occupied, my prediction is that the price of wood will come down, not the opposite. More people can be housed and heated. More biochar can be made to prevent wildfires and regenerate soils. And as more kelp forests are planted, so too will multiply the fish in the sea.
The first line of defense techno-cornucopians raise when I make this argument is how much land would be needed to do all this with natural trees and kelp forests. DAC machines have a much smaller footprint, they argue. But that is incorrect, on both counts. In the lifetime of my parents there were 6 trillion trees on our planet. Now there are fewer than two trillion and at the rate we are going, there will be fewer than one trillion during my lifetime. There is plenty of space. Let us not forget that forests make their own rain and they shelter more than just humans.
One of the favorite tech bro responses to natural climate solutions is that all the biomass on Earth is only 550 GtC (billion tons of carbon). The theory goes that therefore it would be inadequate to sequester the 682 GtC necessary to return the atmosphere and ocean to pre-industrial harmony and therefore we need artificial trees or solar radiation management or some such.
I want to somehow get you to think 4D not 3D. Here is what I mean by that. That 550 GtC is not stable but dynamic. It replaces itself on timescales ranging from minutes to centuries, mostly toward the fast end of the scale.
If we could intercept a large chunk of the decay part of the cycle where dead or burning biomass decomposes and returns to the atmosphere and ocean, then we can rack up continuous withdrawals on the same growing stock.
Here is an example: Wolffia, also known as duckweed, is the fastest-growing green-leaf plant. Most species of duckweed will double every 2 to 3 days. They replace their biomass 100 times per year. They grow as fast or faster overnight as during the day (absorbing carbon from water). If all global plant biomass (495 GtC) were duckweed, the sequestration potential would be 49,500 GtC/y or 181,500 GtCO2. (182 trillion tons of carbon dioxide) Converting that much duckweed to biochar would return the climate to its pre-industrial 280 ppm in 11 hours.
Of course, we are never going to do that, it’s only hypothetical. But now substitute for duckweed all of the useful plants that can be withheld from decay —trees, bamboo, kelp, etc—and not only can we recover the preindustrial atmosphere rapidly but we can provide good livelihoods in the process.
Calculating the footprint of a DAC machine by the area crossed by its shadow is like limiting the radioactive releases of nuclear energy to the reactor, or perhaps just to the control room, and ignoring the entire dirty fuel cycle. What is the ecological and land area footprint of mining ore, smelting it, disposing of mine and mill tailings, transportation, fabrication, construction, maintenance and repair? Of safeguarding the waste for 4.5 billion years? Hint: It is a lot more than 10,000 trees.
When Albert Einstein or Greta Thunberg says we cannot get ourselves out of this pickle with the same kind of mindset that got us into it, they mean we need to challenge our assumptions about a human ability to muster greater intelligence than the whole of the natural world. Mother Nature developed her instincts with a time trial 2000 times longer than human-like creatures have walked the Earth. As an infant, trusting your mother’s instincts, even if you don’t fully understand them, is usually a safe bet.
References:
Lebling, K., Leslie-Bole, H., Byrum, Z., & Bridgwater, L. (2022). 6 Things to Know About Direct Air Capture, World Resources Institute.
Ray, D., The most important climate change paper of 2022 you never heard of (2023).
Meanwhile, let’s end this war. Towns, villages, and cities in Ukraine are being bombed every day. Ecovillages and permaculture farms have organized something like an underground railroad to shelter families fleeing the cities, either on a long-term basis or temporarily, as people wait for the best moments to cross the border to a safer place, or to return to their homes if that becomes possible. There are still 70 sites in Ukraine and 300 around the region. They are calling their project “The Green Road.”
The Green Road is helping these places grow their own food, and raising money to acquire farm machinery and seed, and to erect greenhouses. The opportunity, however, is larger than that. The majority of the migrants are children. This will be the first experience in ecovillage living for most. They will directly experience its wonders, skills, and safety. They may never want to go back. Those that do will carry the seeds within them of the better world they glimpsed through the eyes of a child.
Those wishing to make a tax-deductible gift can do so through Global Village Institute by going to http://PayPal.me/greenroad2022 or by directing donations to greenroad@thefarm.org.
There is more info on the Global Village Institute website at https://www.gvix.org/greenroad
The COVID-19 pandemic destroyed lives, livelihoods, and economies. But it has not slowed climate change, a juggernaut threat to all life, humans included. We had a trial run at emergency problem-solving on a global scale with COVID — and we failed. 6.7 million people, and counting, have died. We ignored well-laid plans to isolate and contact trace early cases; overloaded our ICUs; parked morgue trucks on the streets; incinerated bodies until the smoke obscured our cities as much as the raging wildfires. We set back our children’s education and mental health. We virtualized the work week until few wanted to return to their open-plan cubicle offices. We invented and produced tests and vaccines faster than anyone thought possible but then we hoarded them for the wealthy and denied them to two-thirds of the world, who became the Petri-plates for new variants. SARS jumped from people to dogs and cats to field mice. The modern world took a masterclass in how abysmally, unbelievably, shockingly bad we could fail, despite our amazing science, vast wealth, and singular talents as a species.
Having failed so dramatically, so convincingly, with such breathtaking ineptitude, do we imagine we will now do better with climate? Having demonstrated such extreme disorientation in the face of a few simple strands of RNA, do we imagine we can call upon some magic power that will change all that for planetary-ecosystem-destroying climate change?
As the world emerges into pandemic recovery (maybe), there is growing recognition that we must learn to do better. We must chart a pathway to a new carbon economy that goes beyond zero emissions and runs the industrial carbon cycle backward — taking CO2 from the atmosphere and ocean, turning it into coal and oil, and burying it in the ground. The triple bottom line of this new economy is antifragility, regeneration, and resilience. We must lead by good examples; carrots, not sticks; ecovillages, not carbon indulgences. We must attract a broad swath of people to this work by honoring it, rewarding it, and making it fun. That is our challenge now.
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