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High temperature reduces terrestrial carbon sequestration

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Tom Goreau

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Jan 11, 2025, 6:13:54 AMJan 11
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  • Published: 08 November 2024

Weakening of global terrestrial carbon sequestration capacity under increasing intensity of warm extremes

Nature Ecology & Evolution volume 9pages124–133 (2025)

Abstract

The net ecosystem exchange (NEE), determining terrestrial carbon sequestration capacity, is strongly controlled by climate change and has exhibited substantial year-to-year fluctuations. How the increased frequency and intensity of warm extremes affect NEE variations remains unclear. Here, we combined multiple NEE datasets from atmospheric CO2 inversions, Earth system models, eddy-covariance data-driven methods and climate datasets to show that the terrestrial carbon sequestration capacity is weakened during warm extreme occurrences over the past 40 years, primarily contributed by tropical regions (81% ± 48%). The underlying mechanism can be rooted in the overwhelmingly decreased trend of gross primary productivity compared with terrestrial ecosystem respiration. Additionally, the weakened terrestrial carbon sequestration capacity is mainly driven by the transition from temperature or soil moisture control to vapour pressure deficit control, which is associated with the increasing intensity of warm extremes. Our findings suggest that warm extremes threaten the global carbon sequestration function of terrestrial ecosystems. Therefore, more attention should be given to the evolution of the increasing intensity of warm extremes in future climate projections.

 

Tom Goreau

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Jan 11, 2025, 7:02:54 AMJan 11
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NB, this assumes no forest fires! Western Amazonia is slipping back into drought…..

 

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Ronal Larson

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Jan 11, 2025, 1:10:03 PMJan 11
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Tom,  cc List

This paper is not “non-fee”, so I have requested a copy from first author.

My interest arises because biochar would seem to be an antidote to the Title term “Weakening”.  Do you or any list  member know if that is case and if mentioned in the text?  Does any other CDR approach have same capability?

Thanks for the alert.

Ron




Michael MacCracken

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Jan 11, 2025, 3:10:06 PMJan 11
to Ronal Larson, Thomas Goreau, CarbonDiox...@googlegroups.com

With hillside Chaparral a major fuel source for wildfires and having essentially no other productive use, might harvesting it for conversion to biochar provide the basis as an economic way to also reducing the intensity and impacts of wildfires?

Mike MacCracken

Ronal Larson

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Jan 11, 2025, 3:26:49 PMJan 11
to Mike MacCracken, Thomas Goreau, CarbonDiox...@googlegroups.com, Jonathan Fink
Mike:  and ccs.  Adding Prof. Fink.

Definitely some use of biochar for this purpose.  But can only be deemed “economic” when comparing to the 10’s of billions in fires like this.  I know of no clearing approach more “economic” than biochar.

China has essentially no big fires.  They have a strong policy of clearing.  Maybe involves biochar -  but should and could. I think they have understood the wisdom of both clearing and biochar.

        There is a biochar fire—fighting NASEM webinar coming up Wednesday, Jan 15 at !:00 Pacific.    https://pdx.zoom.us/j/86574942524.  Chair of the Committee is Prof. Jonathan Fink.  (Being cc’d)

Thanks for the question.

Ron

Tom Goreau

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Jan 11, 2025, 3:35:45 PMJan 11
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I only have the abstract so far, but they seem not to discuss fires, the focus is on how high temperature decreases Photosynthesis and increases Respiration, reducing Net Primary Productivity (NPP = P-R), something very long known, but forgotten anew in each generation.

Michael Hayes

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Jan 11, 2025, 5:49:51 PMJan 11
to Tom Goreau, Ronal Larson, CarbonDioxideRemoval@googlegroups.com <CarbonDioxideRemoval@googlegroups.com>

Ron, Tom, et al.,

There is a massive weakening in C uptake in the marine space.

"According to research, oceanic deserts, which are areas of the ocean with very low plant life, are expanding at a rate of around 15% over a decade, with studies showing a significant increase in their size between 1998 and 2007, adding approximately 6.6 million square kilometers of new "desert" area to the oceans; this expansion is largely attributed to warming sea surface temperatures." AI

Growing biomass for soil BC feedstock out in the marine deserts, and on a scale large enough to provide cooling for vast marine areas, can likely help both land and sea C uptake weakening reach true CDR scale. Around 48Mn km2 of land is used for global agriculture, and most of it can use BC. The combined oceanic deserts are ~37Mn km2 in size and rapidly growing.

There are many CDR, SRM, and renewable energy related and individually crafted options, yet we have few individual CDR/SRM/Renewable Energy options that can be better coupled together for synergistic effects, at the volume, and spatial/temporal timescales, as needed than marine BC.

The argument that mBC should not be employed on a vast scale has never been presented in full within this forum. If a member of this CDR expert group wishes to list reasons why mBC should not be a global scale CDR focus, I would greatly appreciate their expert level feedback.

Best regards


Nando Breiter

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Jan 11, 2025, 6:01:58 PMJan 11
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Michael,

I assume that mBC stands for marine biochar or marine black carbon? If so, could you please explain the feedstock sources available, how they would be economically harvested (particularly if there is any cost analysis available, and why these feedstocks might be preferable to those grown on land? If I have misunderstood the acronym, please excuse the question ... 




Michael Hayes

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Jan 11, 2025, 6:37:46 PMJan 11
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Nando and list,

Marine Biochar, or mBC, is biochar that utilizes the full water, energy, and nutrient nexus resources of the maine space for sustainable BC production at CDR scale. The BC itself can be used on land or sea.

The biomass feedstock related questions can be addressed by using many typical agricultural records, and I would predict reactor grown crops will generate significantly better numbers than typical. The type of biomass and how it gets cultivated/processed/transported are all secondary to the type of hull, or reactor, that the mBC operations take place in. At the mCDR scale of ~10 GtC/y, the hull issue is the overall make-or-break issue for reactor-based mCDR and mBC.

Using floating reactor hulls, or floating terrariums and aquariums, has a water, energy, and nutrient nexus advantage over typical fixed site terrestrial croplands as well as reactors offering better disease and predation control over the crops. And, growing crops on floating platforms likely dates back to pre-history. The focus on mBC is a good starting point for CDR scale use of that basic early logic, yet with advanced STEM, policy, and socioeconomic knowledge.

Best regards 

Michael Hayes

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Jan 11, 2025, 6:56:37 PMJan 11
to Nando Breiter, Tom Goreau, Ronal Larson, CarbonDioxideRemoval@googlegroups.com <CarbonDioxideRemoval@googlegroups.com>
My recommendation for the first mBC crop would be Kudzu as it has vine wood for biochar and a microbial symbiot that generates a high amount of bio-ethylene from the Kudzu leaf.

Growing Kudzu in the saltwater environment makes the invasive nature of the plant moot. Processing any shore-based stocks of Kudzu would also be biologically safe due to the enclosed nature of the technology.

There is also a patented microalgae that generates ethylene as a metabolic waste. Providing cultivation and processing space to that group, or to any STEM, policy, and socioeconomic supportable mCDR tech, is a needed priority.

Shannon A. Fiume

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Jan 11, 2025, 6:58:44 PMJan 11
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Maybe targeted harvesting times and quotas to not remove the habitats for lizards, insects, bees, birds and what not. Some of the at risk state's range is in protected and administered by the National Park Service, all of it serviced by Calfire in emergencies.

Some years back All Power Labs was contracted with the state and fire depts to remove some brush while providing power or char. I'm unsure of their current status.

(Signed by a nature goer in N. California coastal range home to native Manzanita, and used to seeing extreme fire danger warnings.)

Best,

~~sa

Nando Breiter

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Jan 11, 2025, 7:12:33 PMJan 11
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As I understand, the biochar would be produced on a floating platform at sea. Assuming electricity and a startup fuel, easiest would be a burnable gas, would both be needed, how would those energy sources be practically produced? In other words, do you have an engineering concept on mind?

Michael Hayes

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Jan 11, 2025, 7:15:14 PMJan 11
to Shannon A. Fiume, Ronal Larson, Mike MacCracken, Thomas Goreau, Carbon Dioxide Removal, Jonathan Fink
Shannon and list,

I grew up in S Texas brush county, and I would focus upon the transportation angle for both biochar and firefighting needs. Selectivity in harvesting is needed more than the typical harvesting methods. Low cost is the top concern, as usual. One current mesquite brush clearing method simply drags a huge chain between 2 huge dozens. 

Balloon logging, a highly selective harvest option, was practices in the PNW back in the early 70s', and it likely can be updated with today's aviation technology and for a wider mission list.


Best regards,

Michael Hayes

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Jan 11, 2025, 7:39:08 PMJan 11
to Nando Breiter, Tom Goreau, Ronal Larson, CarbonDioxideRemoval@googlegroups.com <CarbonDioxideRemoval@googlegroups.com>

The list of marine-based energy conversion options is long. I recommend all focus be placed on oceanic desert operations, and that environment does not have a robust wave energy conversion potential, yet it has a world class solar potential, water thermal differential energy potential, as well as a nutrient/biofuel energy conversion potential.

The hulls will be largely biorock armored thick walled extruded HDPE. Bio-Ethylene production using largely HDPE hulls creates a largely self-replicating reactor hull system of systems engineering plan.

This current engineered HDPE product can be produced in much larger dimensions out in the ocean:

https://youtu.be/qXtVQWHgNig?si=Vgiob1r3wDuz2vjs

The initial CDR MRV accounting can be based completely on the gross weight of the HDPE that is produced. Making HDPE with bio-ethylene creates a C storage system that can have an undeterminably long marine service life as it does not degrade below the phototic zone nor does it biofoul, and it is highly recyclable.

The total C credits for the marine biochar, the initial engineering mission focus, needs to be determined per the type of usage of the biochar.

I hope this helped at the engineering level, best regards.

Greg Rau

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Jan 11, 2025, 7:39:08 PMJan 11
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