A topic near and dear.
From the Washington Post, October 8:
Terradot, a carbon removal company, is using “enhanced rock weathering” to sequester carbon by spreading crushed volcanic rock over farmland.
The technique, known as “enhanced rock weathering,” is emerging as a promising approach to lock away carbon on a massive scale. Some researchers estimate the method has the potential to sequester billions of tons of carbon, helping slow global climate trends. Other major projects are underway across the globe and have collectively raised over a quarter-billion dollars.
As governments around the world fall woefully short of their emissions reduction targets, there is a growing consensus that large-scale carbon removal will be necessary to avoid some of the worst effects of climate change. An analysis conducted by an international team of researchers estimated that the world may need to remove up to 10 gigatons of carbon dioxide a year by 2050 to limit warming to 1.5 degrees Celsius — an amount greater than the annual greenhouse gas emissions of the United States.
Shawn Benner, a hydrogeologist and geochemist who left Boise State University after more than two decades to join Terradot, said he made the decision by asking himself what his grandchildren would want him to do. “Not too many people have the opportunity to change the temperature of the planet,” he said.
Yet significant challenges remain for enhanced rock weathering to meaningfully contribute to reducing global emissions. A key question is whether companies like Terradot can accurately and cost-effectively measure how much carbon they remove. And scaling the process globally poses major logistical hurdles.
“It’s at an exciting juncture,” said David Beerling, director of the University of Sheffield’s Leverhulme Center for Climate Change Mitigation. “But there’s a need for caution in ensuring that we have rigorous, cost-effective [tracking and verification] so that people don’t make claims for carbon credits that aren’t substantiated.”
Geologic to human timescales
Terradot was founded in 2022 at Stanford, growing out of an independent study between James Kanoff, an undergraduate seeking large-scale carbon removal solutions, and Scott Fendorf, an Earth science professor. Terradot ran a pilot project across 250 hectares in Mexico and began operations in Brazil in late 2023.
Since then, the company has spread about 100,000 tons of rock over 4,500 hectares. It has signed contracts to remove about 300,000 tons of carbon dioxide and is backed by a who’s who of Silicon Valley. It expects to deliver its first carbon removal credit — representing one metric ton of verified carbon dioxide removed — by the end of this year and then scale up from there.
Rock weathering is well-studied by scientists. The process acts like a global thermostat. When temperatures are higher, weathering speeds up, pulling carbon dioxide from the atmosphere and helping cool the planet.
Terradot is working to accelerate this process, bringing it from a geological timescale to a human one. It does so by taking basalt, a rock that weathers easily, and grinding it to the texture of baby powder to increase its surface area. The rock is then placed in regions with hot, humid climates for rapid weathering.
Brazil offers an additional benefit: widespread agriculture and plenty of quarries....
....MUCH MORE
Back in 2011 we posted "How They Harvest Soybeans in Brazil" which gives some idea of the scale the Brazilians work on:
Northern Brazil:
Western Brazil:
More Mato Grosso:
And on rock weathering:
June 2025 - Removing Carbon Dioxide From The Air: "A Review of Massively Scalable Enhanced Rock Weathering"
I wanted this on the blog as a personal bookmark, he goes deep....
...Previously:
November 7, 2007 - Engineered weathering process could mitigate global warming
May 9, 2025 - "XPRIZE Makes History, Awards $100M Prize for Groundbreaking Carbon Removal Solutions"
It's not enough just to capture the carbon, to prevent re-release you have to sequester it.
And do so in an affordable way. The rock weathering approach addresses both of those goals.
The next step will be to speed things up.Some background from January 2021:
"Elon Musk to offer $100 million prize for 'best' carbon capture tech"
Carbon capture is an approach the Norwegians among others are exploring but it is not easy. Because the concentrations of CO2 in air are so low, ~415 parts per million, you have to move a lot of air through your systems to get meaningful amounts of CO2 to sequester.
The other reasons are ideological. A lot of folks in the authoritarian crowd don't like it because it means that things don't have to change as much as they would like things to change. Wealth transferers don't like carbon capture because it directly attacks their rationalization for "climate reparations", always set with a starting point far enough back in time so that only Northern Hemisphere and in particular, western, countries owe x-number of trillions of dollars to southern and eastern countries. And then there are the....
Yeah, I've been doing this a long time.
Putting all that aside, prizes are good, a very efficient way to mobilize talent and creativity in a focused pursuit. I may even see if I can recruit a team of folks smarter than I to claim Elon's money....
Oxford Uni.: "The outlook for CO2 removal"
It is still far too expensive to be more than just demonstration projects, now and for another decade minimum.
And
as with all such conversations the promoters never, ever, speak of
degrees of warming avoided. If interested see after the jump.
From Dialogue Earth, June 10:
More clarity needed on CO2 removal in national climate action plans, finds Oxford University report
A nascent industry removing carbon from the atmosphere and storing it in trees, rocks and the ocean will need to quadruple in size by 2050 if the world is to keep temperature rise to within the internationally agreed threshold of 1.5C, a new report has found.
“Carbon dioxide removal” is defined by the UN’s climate science body, the IPCC (Intergovernmental Panel on Climate Change), as human activity that captures CO2 from the atmosphere and stores it for decades to millennia in geological, land or ocean reservoirs, or in products.
Around two billion tonnes of carbon are currently removed in this way each year, mostly using conventional methods such as afforestation and reforestation, wetland restoration and soil improvement.
However, an industry in more novel techniques has seen rapid growth in recent years. Such methods include: storing carbon in products like construction materials or “biochar”, a carbon-rich material produced by heating biomass in an oxygen-limited environment; enhanced rock weathering, which involves spreading finely ground silicate rock onto surfaces to speed up chemical reactions between rocks, water, and air; and direct air carbon capture and storage (DACCS), where carbon is separated from the air using chemical processes and deposited underground.
Last month, the world’s largest commercial DACCS plant, dubbed Mammoth, began operating in Iceland. It will draw down 36,000 tonnes of CO2 from the air every year and store it permanently underground, says the company behind it, Climeworks. The company is planning to build “multiple megaton hubs” in the US, meaning several facilities that can remove a million or more tonnes of CO2 per year.
Today such novel methods remove just 1.3 million tonnes of carbon a year, less than 0.1% of total carbon removals, with conventional methods responsible for the remaining 99.9%, the analysis found. But the researchers behind the report are optimistic that both novel and conventional methods can be scaled up to reach the estimated required level of 7-9 billion tonnes of CO2 per year by 2050.
Taken together, the carbon removal capacity proposed by companies globally would be sufficient to reach this, the authors found. However, they did not assess the likelihood of individual plans or announcements coming to fruition.
Diverse methodsThe report, which was led by academics at the University of Oxford’s Smith School of Enterprise and the Environment, but also involved more than 50 international experts, stresses that politicians, policymakers and business leaders should still be focussing on reducing emissions as the primary way to achieve net zero.But they argue that carbon dioxide removal (CDR) will also be needed to address climate change. CDR is advocated by the IPCC, which cites its potential to reduce emissions in the near term, to counterbalance unavoidable emissions in the medium term, and to achieve net-negative emissions in the longer term....
....MUCH MORE
From the outro of "Reminder of A Reminder of What Net Zero Means":
As always, the correct question to ask of each and every policy is how many degrees C will this proposal reduce the temperature. You don't want the airy-fairy answer in tons of CO₂ or number of automobile-equivalents, you want degrees.
The reason for this is: you have to do comparisons to judge the effectiveness of policy proposals and to do that you have to use the the tools of science (maths).
As we've said over the years - this version is from 2019 but there are many others:
In the last years of the last century there was an international agreement on global warming policy called the Kyoto Protocol. It was a pretty big deal.
It was going to be expensive for the developed economies but worth it.
You heard of it right? It was in all the papers.
And do you recall how much the Kyoto Protocol would cool the planet?
Of course not.
The U.N. and the NGO's and Enron* and the consultants and everybody involved elided right past that number.
The answer was (no, not 42), the answer to the question of how much would the Kyoto Protocol cool the earth was 0.07 degrees. But that's 0.07°C, which is more cooling than if it had been 0.07°F.
The answer was not from me, it's the analysis of the U.S. National Center for Atmospheric Research....****
*The first step is to get honest.
Like this guy, Enron's top lobbyist, John Palmisano, senior director for environmental policy and compliance who emailed from Kyoto:
If implemented [the Kyoto Protocol] will do more to promote Enron’s business than will almost any other regulatory initiative outside of restructuring of the [electricity] and natural gas industries in Europe and the United States…. The endorsement of emissions trading was another victory for us…. This agreement will be good for Enron stock!!It was time to turn deeds into dollars, he added:
Enron now has excellent credentials with many ‘green’ interests including Greenpeace, WWF [World Wildlife Fund], NRDC [Natural Resources Defense Council], GermanWatch, The US Climate Action Network, the European Climate Action Network, Ozone Action, WRI [World Resources Institute], and Worldwatch [Institute],” reported Palmisano. “This position should be increasingly cultivated and capitalized on (monetized).As gentle reader has surmised, we've been following this stuff for a long, long time.
....This has helped form my personal belief that carbon trading is not going to lower world temperature by even a half-a-degree.Tom Wigley of the National Center for Atmospheric Research estimated that Kyoto would result in a reduction from baseline of 0.06°C to 0.21°C . (under one Kyoto scenario 0.06 to 0.11°C, under another 0.11 to 0.21)....Here's the U.S. NCAR 2006 estimate of Kyoto's effects.
For example, in an October 1998 article in Nature, Martin Parry (Co-chair of the IPCC's Working Group II) said the effect of the Kyoto Protocol (and it's associated carbon trading, CDM etc. [articles 6,12 and 17 of the protocol]) would be a reduction of –0.05°C by the year 2050.
