Nature Ecology & Evolution volume 9, pages124–133 (2025)
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.
NB, this assumes no forest fires! Western Amazonia is slipping back into drought…..
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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
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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.
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 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
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
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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.