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Agriculture

Published on December 26th, 2018 | by Michael Barnard

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New Study On Soil Carbon Capture Has Deniers In Rapture

December 26th, 2018 by  


The journal Soil Systems published a study, Non-Flat Earth Recalibrated for Terrain and Topsoil, in November of 2018. Deniers of various stripes are now claiming that this means that global warming isn’t a problem, naturally. It’s worth revisiting the status of carbon capture and sequestration, especially as CleanTechnica has recently published a couple of articles which are much more optimistic than reality warrants for carbon capture in general.

What does the study claim?

Although four to six times IPCC’s or NASA/NOAA’s calculated 1500–2300 Gt SOC, this is likely an underestimation. Global biomass and biodiversity are at least doubled (×2–3.5) and net primary productivity (NPP) increases to >270 Gt C yr due to terrain. Rationale for a ‘Soil Ecology Institute’ gains ground.

It is asserting a vastly different conclusion than the IPCC so that represents an extraordinary claim requiring extraordinary evidence. Is this study extraordinary evidence? No.

Soil Systems was just established in 2017 and has no impact factor ranking, so the quality of the journal is questionable at this point. This is a red flag for reliability of the study. The paper has a single author, also a red flag for quality just as dozens of authors raises concerns. The author Robert J. Blakemore is a PhD and specialist on earthworms, not global soil records as his Google Scholar publishing history attests, so that’s another red flag. Further, he’s affiliated only with VermEcology Japan, which appears to be a WordPress blog. The lack of affiliation to a formal research organization such as a university is another red flag. Once again, this doesn’t mean that the study is incorrect, but it does mean that it cannot be considered as credible against the weight of IPCC meta-analyses.

There’s an even bigger red flag about the Soil Systems journal. The publisher, MDPI, is regarded as a non-academic publisher of predatory journals. The quality of any peer review is likely very low.

MDPI was included on Jeffrey Beall’s list of predatory open access publishing companies in 2014 and was removed in 2015. Beall’s list was shut down in 2017; Beall later wrote that he had been pressured to shut down the list by various publishers, specifically mentioning MDPI. The publisher has been downgraded to non-academic status (level 0) in the Norwegian Scientific Index from 2019.

Even if the study were correct, the utility of the observation is suspect. The best information on how fast soil carbon capture actually removes CO2 from the cycle is that it would take centuries for long term sequestration. While the study referenced suggests miscalculation of the soil volume of the earth, this isn’t useful in terms of being an area amenable to changes in human management. And soil carbon capture requires changing agricultural and forest management practices globally.

It’s worth looking at the scale of the problem and other solutions before returning to soil carbon capture.

There was a similarly optimistic headline on articles globally about a new technology that would work wonders for air carbon capture: Scientists find way to make mineral which can remove CO2 from atmosphere. That was an overstatement, to be polite. CleanTechnica published my assessment of the scale of the CO2 problem and the very poor media coverage about the study: No, Magnesite Isn’t The Magic CO2 Sequestration Solution Either.

There are about 3,200 billion tons of excess CO2 in the air that we’ve added since before the Industrial revolution. […] Assuming that the world decided to go all in on this and could achieve the same scale of production of magnesite, it would only take 267 years to remove 10% of excess atmospheric CO2.

On Quora a couple of years ago, I reviewed the 20-year history of Australia carbon capture and sequestration investments. Note the difference between the 200,000 tons captured and the 3,200 billion ton problem.

About 200,000 tons of CO2 has been captured and sequestered at a cost of over $1 billion AUD since 1998 in various schemes. The cost per ton sequestered was about $4,300 AUD.

Also on Quora, someone asked how many trees it would take to capture the excess carbon, so I did the math on that.

To cover this year’s CO2 emissions alone, we would have to cover 2.7% of the Earth’s surface with newly planted trees, just under 40 billion of them or about 5.4 trees for every human on Earth. We would run out of Earth to plant trees on in under 20 years. To bring us back to pre-Industrial Revolution levels of 250 ppm, we would have to plant about 353 billion trees covering 24% of the Earth’s surface and stop burning all fossil fuels right now. In both cases, it would take 40 years before the trees absorbed the CO2.

Back to soil carbon capture, the pathway to long-term sequestration is through glomalin, a protein on soil fungi.

Data taken from 157 soil samples taken from around the world show the average age of soil carbon is more than six times older than previously thought. This means it will take hundreds or even thousands of years for soils to soak up large amounts of the extra CO2 pumped into the atmosphere by human activity – far too long to be relied upon as a way to help the world avoid dangerous global warming this century.

The scale of the problem requires that all of the areas humans have altered be changed. It doesn’t matter how much of the earth there is to the point of one of the other answers, but how much we have under direct management that is amenable to change. The land we aren’t changing is already doing what it can. That mostly means agricultural land is amenable to changes in soil management practices. How much is there?

At present some 11 percent (1.5 billion ha) of the globe’s land surface (13.4 billion ha) is used in crop production (arable land and land under permanent crops). This area represents slightly over a third (36 percent) of the land estimated to be to some degree suitable for crop production.

That’s in every country in the world and includes everything from subsistence farming to agribusiness. In order to kickstart the soil carbon capture process, we’d have to change the soil management processes for every crop on all of that land in every country in the world, including for all subsistence farmers, a group more given to calorie stripping than good soil management practices. So what would that do?

Let’s make the assumption that all agricultural land globally could be returned to a baseline of the same sequestration as native land over the course of the next 50 years. That means that we’d be at about 1,222 gigatonnes of extra CO2 and the soil would sequester about 150 gigatonnes out of that total, or about 12%.

Temporarily. And hundreds of years later it would be back to normal.

But the normal carbon cycle takes a net carbon molecule out in 200 to 300 years regardless. Changing all soil management practices and not eliminating fossil fuel use doesn’t buy us much. It’s a good thing to do regardless because it has other benefits, but it’s no silver bullet.

This is a weak study in a predatory journal by a non-expert in soil volume which contradicts the systematic review of the IPCC, the most critiqued and carefully managed body of knowledge in the world.

I’ve looked at most carbon capture and sequestration schemes in use today. I’ve done the math. The only answer is to stop emitting greenhouse gases, mostly through burning fossil fuels and leaking refrigerants. Everything else is a very minor wedge. Carbon capture schemes in total might be a 1% wedge at great expense.

Ignore ‘lukewarmers’ who pretend that we don’t have to transform transportation, electrical generation, and the like. They cling to the pretense that there really isn’t a problem, but their confirmation bias blinds them.


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About the Author

is Chief Strategist with TFIE Strategy Inc. He works with startups, existing businesses and investors to identify opportunities for significant bottom line growth and cost takeout in our rapidly transforming world. He is editor of The Future is Electric, a Medium publication. He regularly publishes analyses of low-carbon technology and policy in sites including Newsweek, Slate, Forbes, Huffington Post, Quartz, CleanTechnica and RenewEconomy, and his work is regularly included in textbooks. Third-party articles on his analyses and interviews have been published in dozens of news sites globally and have reached #1 on Reddit Science. Much of his work originates on Quora.com, where Mike has been a Top Writer annually since 2012. He's available for consulting engagements, speaking engagements and Board positions.



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